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TEST NAME: CHEMISTRY EOG QUESTIONS TEST ID: 194674 GRADE: 08 SUBJECT: Life and Physical Sciences TEST CATEGORY: My Classroom CHEMISTRY EOG QUESTIONS Page 1 of 59 Student: Class: Date: 1. The formula for glucose is C6H12O6. If glucose is broken down by a reaction, then how many atoms of carbon should be present in the products? A. 1 B. 6 C. 12 2. Which best explains how the periodic table is used to identify properties of elements? A. by the color and shape of the elements B. by the number of electrons in the elements C. by the group in which the elements are located 3. Which indicates a chemical reaction is occurring? A. a substance melting B. a substance evaporating C. bubbles forming when two substances are mixed D. temperature remaining the same when two substances are mixed 4. On the periodic table, in which group is the metalloid silicon found? A. Group 3 B. Group 14 C. Group 15 5. Which is a compound? A. B. C. D. CHEMISTRY EOG QUESTIONS Page 2 of 59 6. Which characteristic property of iron is most closely related to the formation of rust? A. chemical reactivity B. melting point C. specific heat D. solubility 7. When a mixture of oxygen and hydrogen is ignited in a test tube, the reaction shown occurs. What happens to the total mass of the contents of the test tube? A. The total mass increases. B. The total mass decreases. C. The total mass remains the same. D. Part of the mass is changed to heat energy. 8. A sealed test tube containing 8 grams of iron filings and 5 grams of sulfur is heated until the material in the test tube glows bright red. Which is true about the reaction? A. The product will have a mass of 13 grams. B. The product will have a mass less than 13 grams. C. The product will have a mass greater than 13 grams. D. The mass of the product cannot be determined. 9. Which of the following elements is the most reactive? A. calcium (Ca) B. strontium (Sr) C. beryllium (Be) D. magnesium (Mg) CHEMISTRY EOG QUESTIONS Page 3 of 59 10. Which property would be most useful in placing a newly discovered element in Group 18 (VIIIA) on the periodic table? A. reactivity B. malleability C. conductivity D. nonreactivity 11. Which is true of a chemical equation? A. Products and reactants must be balanced. B. Subscripts must be used with all products and reactants. C. Energy must be included in the beginning of the reaction. D. Coefficients must be used with all products and reactants. 12. In which groups did Mendeleev most likely place highlyreactive elements? A. IA and VIIA B. IA and VIIIA C. IIA and VIIIA 13. A chemist is looking for an element that reacts similarly to the element lithium (Li). Which would be the best choice? A. gold (Au) B. neon (Ne) C. fluorine (F) D. sodium (Na) 14. Substance A has a mass of 7 grams. When substance A was mixed with substance B, a new substance was formed. Which statement best describes the Law of Conservation of Mass? A. The mass of substance B is equal to the mass of the product. B. The mass of the product is equal to the mass of the reactants. C. The mass of the product is less than the mass of the reactants. CHEMISTRY EOG QUESTIONS Page 4 of 59 15. When chemicals react in a closed container, which must be true? A. The mass both before and after the reaction is the same. B. The mass both before and after the reaction is variable. C. The same number of compounds is present both before and after the reaction. 16. Which subatomic particles determine the reactivity of groups of elements in the periodic table? A. electrons B. neutrons C. protons 17. Each of the elements in the periodic table has a specific number. What does this number represent? A. the halflife B. the number of neutrons C. the number of protons 18. What is the ratio of elements in glucose (C6H12O6)? A. 1:1:1 B. 1:2:1 C. 2:3:2 D. 2:6:2 19. Which best describes a chemical reaction occurring? A. boiling water B. color change C. ice melts CHEMISTRY EOG QUESTIONS Page 5 of 59 20. In order to form water, two hydrogen atoms and one oxygen atom must be A. mixed. B. divided. C. bonded. D. dissolved. 21. Which best describes a heterogeneous mixture? A. It contains only one type of atom. B. It is composed of two or more elements in a fixed pattern. C. It contains two or more types of particles which are easily distinguished. D. It is composed of two or more substances in which particles are evenly blended. 22. What is the smallest unit of an element that retains the properties of that element? A. electron B. molecule C. neutron D. atom 23. Which molecule is produced by the transferring of electrons? A. glucose B. caffeine C. sodium chloride 24. Which is the best term to describe a chemical reaction that absorbs heat energy? A. catalytic B. exothermic C. endothermic CHEMISTRY EOG QUESTIONS Page 6 of 59 25. The amount of energy required to raise one gram of a substance 1°C can be used to identify unknown substances. Which term best describes this property? A. solubility B. specific heat C. melting point D. chemical reactivity 26. Sodium reacts with water. Which element is most likely to have a similar effect to sodium if it is exposed to water? A. carbon B. oxygen C. lithium 27. Which best represents an element? A. CHEMISTRY EOG QUESTIONS Page 7 of 59 B. C. D. CHEMISTRY EOG QUESTIONS Page 8 of 59 28. Which is a homogeneous mixture? A. pizza B. vinegar C. concrete D. woven fabric 29. Which is true about the compounds carbon monoxide (CO) and carbon dioxide (CO2)? A. The compounds have the same properties because they are both gases. B. The compounds have the same properties because they contain the same elements. C. The compounds have different properties because they are found in different amounts in the atmosphere. D. The compounds have different properties because they contain the same elements in different quantities. 30. In a chemical reaction, what is the best description of a molecule’s movement when the temperature decreases? A. movement decreases B. movement increases C. movement stays the same 31. What observation would be made if a precipitate reaction will have occurred? A. bubbles B. change in color C. cloudy solution CHEMISTRY EOG QUESTIONS Page 9 of 59 32. Which best explains why conservation of mass should be studied in a closed system? A. to prevent the loss of any reactants B. to prevent contamination of the products C. to prevent the release of any gases produced D. to prevent the absorption of heat from the outside 33. A potter molded wet clay into the shape of a bowl and let it dry. The potter knows that the clay went through a physical change when it became a bowl because the bowl A. is a different color than the wet clay. B. is the same substance as the wet clay. C. has a different texture than the wet clay. D. holds the same amount of water as the wet clay. 34. What is the best evidence for a chemical reaction? A. color change B. cutting a metal C. change of state 35. How many elements are in one molecule of glucose (C6H12O6)? A. 1 B. 3 C. 6 CHEMISTRY EOG QUESTIONS Page 10 of 59 36. How many atoms are in one formula unit of the compound FeC5O5? A. 5 B. 11 C. 15 D. 26 37. Which element is in the same family as chlorine (Cl) and fluorine (F)? A. hydrogen (H) B. lithium (Li) C. oxygen (O) D. bromine (Br) 38. Which best explains how elements combine in different ways to produce compounds? A. state of matter B. chemical reactivity C. similar physical properties D. matching atomic numbers 39. A sea creature releases a liquid into the ocean that reacts with the water to form a seashell. Which process does this represent? A. freezing B. gas formation C. change of state D. precipitate formation 40. Which part of digestion is mainly a chemical change? A. Teeth break food into small pieces. B. Throat muscles push food toward the stomach. C. Stomach acids dissolve food into nutrients. D. Intestinal cells transport nutrients into the blood. CHEMISTRY EOG QUESTIONS Page 11 of 59 41. Which element is more likely to react with sodium (Na)? A. magnesium (Mg) B. aluminum (Al) C. oxygen (O) D. radon (Rn) 42. Which most accurately represents the changes in the physical state of elements in Period 4? A. B. C. D. Groups 1 (IA) 16 (VIA)Group 17 (VIIA)Group 18 (VIIIA) gas liquid solid Groups 1 (IA) 16 (VIA)Group 17 (VIIA)Group 18 (VIIIA) liquid gas solid Groups 1 (IA) 16 (VIA)Group 17 (VIIA)Group 18 (VIIIA) solid liquid gas Groups 1 (IA) 16 (VIA)Group 17 (VIIA)Group 18 (VIIIA) solid gas liquid 43. When 15 grams of zinc are combined with 20 grams of hydrochloric acid, two new products are created. What will be the combined weight of the products? A. 5 grams B. 15 grams C. 20 grams D. 35 grams 44. A student finds that an unknown element readily reacts with alkali metals. Which is the best conclusion about the unknown element? A. It is a noble gas. B. It is in Group 16 (VIA). C. It is in Group 17 (VIIA). D. It is an alkaline earth metal. CHEMISTRY EOG QUESTIONS Page 12 of 59 45. A scientist placed a sample of lithium into a container of water. The scientist observed the lithium floating and making a buzzing sound as gas bubbles were forming around it. Which conclusion is best supported by this observation? A. A chemical change took place. B. The lithium was dissolved by the water. C. Dissolved gases were released. D. Water was vaporized. 46. Which best represents a balanced equation? A. HgO Hg + O2 B. 2Fe + O2 Fe2O3 C. 2H2 + O2 2H2 O 47. A teacher has 100 g of Reactant X and 150 g of Reactant Y for her class demonstration. After combining the two reactants, how much product should she have? A. 50 g B. 100 g C. 150 g D. 250 g 48. Which action results in a chemical change? A. apples being cut into slices B. wood burning in a fireplace C. wet clothes drying on a clothesline D. snow being shoveled off of a sidewalk 49. When frozen carbon dioxide is heated, it changes directly into a gas. Which statement best indicates that a physical change has taken place? A. Heat caused an increase in gas production. B. Heat caused a new substance to form. C. Heat caused a decrease in energy. D. Heat caused a change in state. 50. A science class is studying the states of matter. One group of students freezes 100 grams (g) of water in a cup. Another group of students melts 50 g of ice in a cup. Which of these will most likely occur at the end of the experiment? A. The temperature of both cups will be the same. B. Both samples in the cups will be in the same state. C. Both groups will have the same mass with which they started. D. The time required for the changes in states of matter will be the same. CHEMISTRY EOG QUESTIONS Page 13 of 59 51. A student observes tiny bubbles after combining 25 g of baking soda with 100 mL of vinegar in a beaker. The student measures the mass of the mixture after 5 minutes. What is the most likely outcome? A. a physical change and decrease in mass B. a physical change and increase in mass C. a chemical change and decrease in mass D. a chemical change and increase in mass 52. A substance is found containing two types of atoms. Some atoms have 3 protons, 4 neutrons and 3 electrons, while other parts of the sample have 3 protons, 3 neutrons and 3 electrons. Which is most likely the substance? A. ion B. element C. mixture 53. Which best describes Groups 3 (IIIB) through 12 (IIB) of the periodic table? A. alkaline earth metals B. transition metals C. metalloids D. nonmetals 54. How are the properties of elements related to the properties of the compounds they make? A. The properties of the compound are always the same as the properties of the elements. B. The properties of the compound are completely different than the properties of the elements. C. The element in the compound with the largest number of atoms gives the compound its properties. D. The element in the compound with the smallest number of atoms gives the compound its properties. CHEMISTRY EOG QUESTIONS Page 14 of 59 55. Sodium (Na) reacts with sulfur (S) to form a compound in the ratio of two sodium atoms to one sulfur atom. Element X also reacts with sodium in the ratio of two sodium atoms to one element X atom. Which is most likely the identity of element X? A. argon (Ar) B. chlorine (Cl) C. oxygen (O) D. phosphorus (P) 56. Which is one characteristic of some pure substances? A. They cannot be changed into simpler substances. B. They can be homogeneous or heterogeneous. C. They contain different types of molecules. 57. Sodium (Na) and chlorine (Cl) combine to form table salt (NaCl). How many sodium (Na) atoms are there for every chlorine atom (Cl)? A. two sodium (Na) atoms for every one chlorine (Cl) atom B. one sodium (Na) atom for every one chlorine (Cl) atom C. one sodium (Na) atom for every two chlorine (Cl) atoms 58. Which best describes elements found in a column of the periodic table? A. The elements have the samesize atoms. B. The elements have the same atomic number. C. The elements have similar chemical properties. D. The elements are all found naturally in the same physical state. 59. Which is represented when liquid water becomes a gas at 100°C? A. density of water B. solubility of water C. boiling point of water D. chemical reactivity of water CHEMISTRY EOG QUESTIONS Page 15 of 59 60. Which demonstrates a chemical change? A. ice melting in a warm soda B. molten gold freezing to form a ring C. breaking a cold pack, causing a sudden drop in temperature 61. Which is a mixture? A. H2O B. salad C. table salt 62. Which of these will best separate iron filings from sand? A. water B. a magnifying glass C. a magnet D. rubbing alcohol 63. Based on how the atoms are packed together in arrangements, which is an element? A. glass B. carbon C. silver nitrate 64. Which best describes how carbon dioxide and salt are similar? A. They are both mixtures made up of atoms from a single element. B. They are both compounds made up of atoms from a single element. C. They are both mixtures made up of atoms from two different elements. D. They are both compounds made up of atoms from two different elements. CHEMISTRY EOG QUESTIONS Page 16 of 59 65. Equal amounts of two unknown liquids, X and Y, are poured into a beaker. Liquid Y settles to the bottom. Water is added and settles in between X and Y. What can most likely be concluded from this experimental design? A. The three liquids chemically combine, and liquid Y settles out as a precipitate. B. The three liquids remain separate because they have different physical properties. C. Liquids X and Y chemically combine, but the water reverses the reaction when added. D. Water chemically combines with liquid X, but does not chemically combine with liquid Y. 66. Where on the periodic table is a metal element most likely found? A. middle B. bottom C. left side D. right side 67. Which element belongs in the least reactive group of elements on the periodic table? A. neon (Ne) B. silver (Ag) C. carbon (C) D. potassium (K) CHEMISTRY EOG QUESTIONS Page 17 of 59 68. In the equation below, suppose 11 grams of zinc react with 12 grams of hydrogen chloride to form 16 grams of zinc chloride and an unknown amount of hydrogen gas. Zn + 2HCl → ZnCl2 + H2 Based on the Law of Conservation of Mass, how many grams of hydrogen gas will form? A. 1 gram B. 7 grams C. 19 grams 69. Max combines baking soda and vinegar in a flask. Which is the most likely reason Max should place a balloon over the mouth of the flask before he mixes the two substances? A. to prevent any gas formed as a product from escaping during the reaction B. to prevent any liquid used as a reactant from escaping during the reaction C. to prevent any powder used as a reactant from escaping during the reaction D. to prevent any liquid formed as a product from escaping during the reaction 70. Which best describes the type of change that occurs when liquid water freezes to become ice? A. physical change in which the ice is less dense than the liquid water B. chemical change in which the ice is less dense than the liquid water C. physical change in which the ice is more dense than the liquid water D. chemical change in which the ice is more dense than the liquid water CHEMISTRY EOG QUESTIONS Page 18 of 59 71. Which term correctly describes all of the following materials? saltwater, vinegar, bronze, air, beach sand A. compounds B. mixtures C. solutions D. elements 72. Which best demonstrates a physical change? A. change in temperature B. formation of a gas C. change in state 73. If a student is chemically combining 4 g of hydrogen with 2 g of oxygen, what will be the mass of the product? A. 4g B. 6g C. 8g D. 10g 74. Which represents a compound? A. air B. iron C. soil D. water CHEMISTRY EOG QUESTIONS Page 19 of 59 75. Sugar is dissolved in a glass of hot water until no more sugar will dissolve. As the glass of hot water cools, a white crystalline solid is observed on the bottom of the glass. Which best describes the identity of the white crystalline solid? A. The white crystalline solid is sugar. B. The white crystalline solid is an impurity in the water. C. The white crystalline solid is produced from the mixture of sugar and water. 76. The compound potassium sulfate, , is composed of A. 2 atoms of potassium, 1 atom of sulfur, and 4 atoms of oxygen. B. 2 atoms of potassium, 4 atoms of sulfur, and 4 atoms of oxygen. C. two molecules of potassium and one molecule of sulfate. D. one molecule of potassium and two molecules of sulfate. 77. A researcher uses several procedures to separate a rock sample into different chemicals. A mass of 50 grams of one chemical is produced. If this chemical cannot be separated into other chemicals, then it is best described as A. a compound. B. a mixture. C. a solution. D. an element. 78. How many copper atoms and how many chlorine atoms are in a molecule of CuCl2? A. one copper atom, one chlorine atom B. one copper atom, two chlorine atoms C. two copper atoms , one chlorine atom 79. Which best explains how atoms combine to form compounds? A. The atoms in the compound share electrons. B. The atoms in the compound share neutrons. C. The atoms in the compound share protons. CHEMISTRY EOG QUESTIONS Page 20 of 59 80. Water (H2O) and table salt (NaCl) can be combined to form salt water. How can this combination be classified? A. as a compound because the water (H2O) and table salt (NaCl) are chemically combined B. as a compound because the water (H2O) and table salt (NaCl) form a new pure substance C. as a mixture because the water (H2O) can be evaporated and physically separated from the table salt (NaCl) 81. When potassium and bromine atoms form chemical bonds, which of these is produced? A. an element B. a mixture C. a compound D. a new form of matter 82. Which substance is most likely an element? A. It can be changed into simpler substances, solid at room temperature, and can be heterogeneous or homogeneous. B. It cannot combine with other substances, liquid at room temperature, and cannot be changed into simpler substances. C. It is solid at room temperature, can be broken down from compounds by chemical changes, and composed of one kind of atom. 83. How are elements ordered in the modern periodic table? A. by date of discovery B. by decreasing atomic mass C. by increasing atomic number D. by alphabetical order of element symbols 84. As a glass of carbonated water is at room temperature, small bubbles are observed to form on the inside surface of the glass. Which best describes the identity of the bubbles observed on the inside surface of the glass? A. The bubbles are oxygen gas from the water. B. The bubbles are hydrogen gas from the water. C. The bubbles are carbon dioxide used to carbonate the water. CHEMISTRY EOG QUESTIONS Page 21 of 59 85. The conversion of 7.0 grams of carbon monoxide and 7.5 grams of nitrogen monoxide using 3.0 grams of platinum catalyst is shown below. Which best represents the total mass of carbon dioxide and nitrogen gases produced in this process? A. 3.5 grams B. 10.5 grams C. 14.5 grams 86. The elements on the far right side of the periodic table have which characteristic in common? A. ductility B. high reactivity C. electrical conductivity D. found in elemental form in nature 87. Which of these shows a physical change? A. Wood is burned in a fireplace. B. Cake batter is baked in an oven. C. A blue liquid and a yellow liquid mix and make a green liquid. D. Baking soda is mixed with vinegar to make carbon dioxide gas. 88. What chemical reaction results in the formation of a solid? A. acid base reaction B. endothermic C. precipitate CHEMISTRY EOG QUESTIONS Page 22 of 59 89. The table below shows several minerals found in Earth’s crust. Based on the information in the table, which mineral is also an element? A. graphite B. quartz C. calcite D. hematite 90. If a chemical reaction starts with 10 times the amount of oxygen and hydrogen atoms shown, which best describes the amount of product? 2H2 + O2 → 2H2O A. There would be 1 less water molecule produced. B. There would be 10 times more water molecules produced. C. There would be 20 times more water molecules produced. D. There would be the same amount of water molecules produced. 91. What is the best description of what has happened to flowers when they change color as they mature? A. a formation of a mixture B. a chemical reaction C. a physical reaction CHEMISTRY EOG QUESTIONS Page 23 of 59 92. A student mixed 10 grams of a powdery substance with 200 grams of an acid solution. A bubbly solution weighing 205 grams was formed. Which best explains why the mass of the new solution does not equal the mass of the reactants? A. The other 5 grams changed color. B. The other 5 grams created a precipitate. C. The other 5 grams were released as a gas. D. The other 5 grams weighed less in the acid. 93. Which elements are the least reactive on the periodic table? A. halogens B. noble gases C. alkali metals 94. Which of these are broken down during chemical, but not physical, changes? A. elements B. mixtures C. solutions D. compounds 95. Which is an example of a chemical reaction? A. Vinegar added to baking soda forms a gas. B. Water evaporates into air. C. Sugar dissolves in water. D. Corn kernels are crushed to form flour. 96. How many protons are in a sodium atom? A. Sodium has 1 proton. B. Sodium has 3 protons. C. Sodium has 11 protons. CHEMISTRY EOG QUESTIONS Page 24 of 59 97. Which property determines the chemical reactivity of an element? A. atomic structure B. solubility C. density D. volume 98. The properties of element X are shown below. Which best represents the arrangement of atoms in a sample of element X? Properties of Element X definite volume definite shape malleable ductile conductor of electricity conductor of heat A. B. CHEMISTRY EOG QUESTIONS Page 25 of 59 C. D. 99. Which of these is a composite material? A. a glass window B. a bronze statue C. an aluminum can D. a fiberglass bumper 100. What number and types of atoms occur in a formula unit of A. 1 carbon atom, 1 neon atom, and 6 oxygen atoms B. 1 calcium atom, 2 neon atoms, and 3 oxygen atoms C. 1 carbon atom, 1 nitrogen atom, and 3 oxygen atoms D. 1 calcium atom, 2 nitrogen atoms, and 6 oxygen atoms 101. Which is the best example of a heterogenous mixture? A. sugar B. brass C. salad D. salt water CHEMISTRY EOG QUESTIONS Page 26 of 59 102. Food spoiling is a chemical reaction. What is the best way to keep food fresh and edible? A. Leave the food on the counter at room temperature. B. Put the food in the refrigerator. C. Wrap food in aluminum foil. 103. The drawing shows solid carbon dioxide changing into carbon dioxide gas. Which statement describes the relationship between the solid carbon dioxide and the carbon dioxide gas after all of the solid has changed to gas? A. They have the same volume. B. The gas has less volume than the solid. C. They have the same mass. D. The gas has less mass than the solid. 104. When two clear solutions are mixed together in equal amounts, a solid bright yellow substance settles out of the solution. Which best describes what has occurred? A. A physical change created a new yellow solution. B. A chemical change created a new yellow solution. C. A physical change created a new yellow precipitate. D. A chemical change created a new yellow precipitate. 105. If 100 grams of vinegar and 5 grams of baking soda are poured in a container, a small amount of gas will be produced. What will the final mass of the products be if the gas is trapped in the container? A. 100 grams B. 104 grams C. 105 grams D. 110 grams CHEMISTRY EOG QUESTIONS Page 27 of 59 106. Which best explains why scientists have arranged elements number 57 to 102 apart from the rest of the elements of the periodic table? A. They all have unique properties that set them apart. B. They are all radioactive. C. They are all synthetic. 107. Properties such as magnetism, luster, and malleability have been used to group together which category of elements on the periodic table? A. metals B. nonmetals C. metalloids D. noble gases 108. Which physical property is most important in choosing the right chemicals for a fireworks show? A. the odor B. the color C. the weight 109. How does the zigzag line on the periodic table help indicate properties of elements? A. Elements located on the left of the zigzag line are liquids at room temperature. B. Elements located on the right of the zigzag line are liquids at room temperature. C. Elements located on the left of the zigzag line are good conductors of heat and electricity. CHEMISTRY EOG QUESTIONS Page 28 of 59 110. When water boils, water vapor is produced and escapes into the air. Which best describes this change? A. melting B. freezing C. physical change D. chemical change 111. Which of these best describes a change that is physical? A. yarn being knitted into a sweater B. the engine from a tractor being started C. the metal on a bicycle forming rust D. grass capturing the energy from sunlight 112. How can the element carbon be classified? A. metal B. metalloid C. nonmetal 113. Which best describes how the current periodic table is arranged? A. by atomic mass B. by atomic number C. in alphabetical order by element symbol D. in numerical order by number of neutrons in the nucleus 114. A piece of paper burns, producing heat and light. Which best describes the process of burning? A. Burning is a physical change. The paper mixes with the oxygen in the air, producing heat and light. B. Burning is a chemical change. The paper reacts with the oxygen in the air, producing heat and light. C. Burning is a physical change. The paper changes from a solid to a gas, producing heat and light. D. Burning is a chemical change. The paper breaks down in sunlight, producing heat and light. CHEMISTRY EOG QUESTIONS Page 29 of 59 115. Which is indicated if a gas forms when two or more substances are mixed? A. physical change B. chemical change C. physical property D. chemical property 116. Which element is a member of the halogen family? A. helium (He) B. oxygen (O) C. sodium (Na) D. chlorine (Cl) 117. When oxygen combines with hydrogen, which substance is formed? A. water B. vinegar C. hydrochloric acid D. hydrogen dioxide 118. Which most likely indicates formation of a precipitate during the reaction of two liquids? A. the liquids changing colors B. a solid appearing in the liquid C. gas bubbles appearing in the liquid D. the temperature of the liquids changing 119. Sodium chloride (NaCl) is formed in a chemical reaction between sodium (Na) and chlorine ( ). What is sodium chloride? A. an element B. a mixture C. a compound D. an atom CHEMISTRY EOG QUESTIONS Page 30 of 59 120. How many methane (CH4) molecules would be needed to produce 13 carbon dioxide (CO2) molecules? CH4 + 2O2 → CO2 + 2H2O A. 4 B. 13 C. 26 D. 52 121. Chemical formulas for several common substances are listed in the table below. Substance water ammonia sugar baking soda Formula H20 NH3 C6H12O6 NaHCO3 Why does hydrogen (H) have a different subscript in each substance? A. The subscript indicates the number of hydrogen atoms in each substance. B. The subscript indicates the number of mixtures that the hydrogen is forming. C. The subscript indicates the number of compounds that the hydrogen is forming. D. The subscript indicates whether the hydrogen is forming a compound or a mixture. 122. A chemist observed bubbling and fizzing after adding an acid solution to a white powdery substance in a beaker. Which of the following can be inferred? A. The acid boiled when poured into the beaker. B. The acid and powder formed a new product. C. A physical reaction produced a gas mixture. D. A reaction occurred that produced heat. CHEMISTRY EOG QUESTIONS Page 31 of 59 123. In which state of matter will the atoms of an element be tightly packed together? A. gas B. liquid C. solid 124. Which best represents a heterogeneous mixture? A. vegetable oil B. sand at the beach C. a solution of sugar and water D. a solution of oxygen gas and nitrogen gas 125. A student sees the diagram shown in a textbook. What does the symbol in the diagram represent? A. a compound B. an element C. a molecule D. an isotope 126. Which best explains how the atomic size of the elements is arranged in the periodic table? A. The atomic size of the elements decreases from left to right and decreases from top to bottom. B. The atomic size of the elements increases from left to right and increases from top to bottom. C. The atomic size of the elements decreases from left to right and increases from top to bottom. 127. Which statement best describes the formation of rust? A. Rust results from a physical mixing of iron with water. B. Rust forms from a chemical breakdown of old metal. C. Rust results from a chemical reaction between iron and water. D. Rust forms from a physical change when wind blows against metal. CHEMISTRY EOG QUESTIONS Page 32 of 59 128. Sodium sulfate and barium chloride react with each other to form sodium chloride and barium sulfate as shown. Which statement most accurately describes the mass of the reactants compared to the mass of the products? A. The mass of the reactants is the same as the mass of the products. B. The products have a greater mass because matter was created during the reaction. C. The reactants have a greater mass because some of the mass was converted to heat. D. The reactants have a greater mass because some matter was destroyed by the reaction. 129. Which is true about a compound? A. It is made up of one type of atom. B. It can be formed through a physical reaction. C. It can be changed into simpler substances through a physical change. D. It is a pure substance containing elements that are chemically combined. 130. Liquid gasoline burns in a car’s engine and undergoes a chemical change. Which provides evidence of the chemical change? A. The liquid is converted into a solid state, and heat is absorbed. B. The liquid is converted into a gaseous state, and heat is produced. C. The liquid is converted into a solid state, and a precipitate is formed. D. The liquid is converted into a gaseous state, and a precipitate is formed. CHEMISTRY EOG QUESTIONS Page 33 of 59 131. Which element in Period 3 is known to be a highly reactive metal? A. sulfur (S) B. argon (Ar) C. sodium (Na) D. scandium (Sc) 132. When baking soda and vinegar react, the product includes bubbles. What has most likely occurred? A. gas formation B. exothermic reaction C. precipitate formation 133. A chemical change happens when A. glass breaks into pieces. B. dough bakes in an oven. C. ice cream melts into a liquid. D. electricity flows through a wire. 134. Which best describes a solid produced in a solution during a chemical reaction? A. acid B. solute C. reactant D. precipitate 135. Separating carbon dioxide from a solution of carbonated water is most rapidly accomplished by A. lowering the temperature of the carbonated water and increasing the pressure above the surface of the carbonated water. B. lowering the temperature of the carbonated water and decreasing the pressure above the surface of the carbonated water. C. increasing the temperature of the carbonated water and increasing the pressure above the surface of the carbonated water. D. increasing the temperature of the carbonated water and decreasing the pressure above the surface of the carbonated water. CHEMISTRY EOG QUESTIONS Page 34 of 59 136. Which property of sodium (Na) can be determined based on its location on the periodic table? A. It is a solid metal at room temperature. B. It is a liquid metal at room temperature. C. It is a solid nonmetal at room temperature. 137. A chemical reaction occurs in a sealed test tube. As the result of the reaction, 24 grams of product are produced. Which is most likely true? A. The mass of the reactants was 24 grams. B. The mass of the reactants was less than 24 grams. C. The mass of the reactants was more than 24 grams. D. The mass of the reactants is not related to the 24 grams of product. 138. The compound ammonia is composed of nitrogen and hydrogen atoms. If two atoms of nitrogen completely react with six atoms of hydrogen to form two molecules of ammonia, which best describes the number of hydrogen atoms present in the two molecules of ammonia? A. two hydrogen atoms B. four hydrogen atoms C. six hydrogen atoms 139. Which term describes the relationship between the mass and volume of a substance? A. density B. solubility C. specific heat D. melting point 140. Which elements would have similar properties to those of potassium? A. lithium and sodium B. bromine and krypton C. calcium and scandium CHEMISTRY EOG QUESTIONS Page 35 of 59 141. A chemical reaction is represented by the equation below. BeO + 2NaCl → Na2O + _______ Which substance would make the equation true and balanced? A. BeO B. BeCl2 C. Be2Cl 142. Which task in the kitchen is an example of a physical change? A. frying an egg B. baking a cake C. melting butter D. toasting bread 143. The physical properties of element X are shown in the table below. Physical Properties of X malleable ductile shiny conducts heat conducts electricity Which most likely represents the identity of element X? A. carbon (C) B. copper (Cu) C. iodine (I) D. sulfur (S) 144. Read the equation. What is the product of the reaction? A. metal B. mixture C. solution D. compound CHEMISTRY EOG QUESTIONS Page 36 of 59 145. Jerome mixes two clear liquids together and observes the clear liquids turn cloudy white. Based on his observations, which most likely occurred? A. Heat was given off. B. Rust was produced. C. The mass increased. D. A precipitate formed. 146. What best explains the result of substances of a chemical reaction? A. A new substance is produced. B. The same substance is produced. C. More energy is produced in the substance. 147. Which best represents a balanced equation? A. Mg(s) + 2O2(g) B. Mg(s) + O2(g) C. 2Mg(s) + O2(g) 2MgO(s) 2MgO(s) 2MgO(s) 148. When burning methane gas, which outcome best demonstrates the law of conservation of mass? A. CH4 → CO2 + H20 B. CH4 + O2→ CO2 + 2H20 C. CH4 + O2 → 2CO2 + 2H20 D. CH4 + 2O2 → CO2 + 2H20 149. What is the significance of metalloids in the periodic table? A. They separate liquids from solids. B. They separate metals from nonmetals. C. They combine elements and compounds. CHEMISTRY EOG QUESTIONS Page 37 of 59 150. What is the best evidence that a gas has been produced in a chemical reaction? A. change in color B. formation of bubbles C. change in temperature 151. What is the best way to measure the gas produced in a chemical reaction? A. Perform the experiment in a beaker. B. Perform the experiment in a room. C. Perform the experiment in a closed system. 152. Element X reacts with the elements of Group 17 (VIIA) of the periodic table. The compounds produced in these reactions have one atom of element X for every one atom of a Group 17 element. To which group does element X most likely belong? A. Group 1 (IA) B. Group 2 (IIA) C. Group 13 (IIIA) D. Group 16 (VIA) 153. Read the chemical equation. CH4 + 2O2 CO2 + 2H2O + energy What is the best description for this equation? A. Energy is absorbed. B. Energy is released. C. Energy stays the same. 154. How many atoms are in one formula unit of magnesium hydroxide, A. 6 B. 5 C. 4 D. 3 CHEMISTRY EOG QUESTIONS Page 38 of 59 155. A balloon is filled with 1 liter of air. Which would most likely cause an increase in the volume of the balloon? A. increase the pressure on the balloon B. increase the temperature of the balloon C. decrease the mass of the gas in the balloon 156. Over time, a silver ring may become tarnished. This shows which chemical change? A. combustion B. neutralization C. change in color 157. If it is determined that the particles in one solid are arranged in a repeating pattern and the particles in another solid are arranged randomly, what must be true about the solids? A. They are different substances. B. They have the same weight. C. They have the same densities. D. They are different mixtures. 158. Which best describes a substance that changes from a liquid to a solid? A. The substance gains mass. B. The substance gains volume. C. The substance undergoes a physical change. D. The substance undergoes a chemical change. 159. A experiment was conducted to test the law of conservation of mass. At the end of the experiment, only 82% of the mass of the initial reactants was present. The experiment was repeated three times with similar results. Which best explains why some of the mass was lost? A. The mass escaped as a gas. B. The mass transformed into a liquid. C. The mass remained part of the reactant. D. The mass turned into a heavier chemical. CHEMISTRY EOG QUESTIONS Page 39 of 59 160. If an element has no electrons to share and is stable, what family is it found in? A. alkali metals B. noble gases C. halogens 161. Which is an example of a mixture? A. sodium chloride B. fruit punch C. water 162. Students performed an investigation on how aluminum cans taken to a recyle center were able to be reused. They found out an aluminum can undergoes which type of change? A. a physical change because the can is heated B. a chemical change because new metal is formed C. a physical change because the material remains the same D. a chemical change because an old can is changed into a new can 163. A student performs an experiment and the results are shown below: Before— Iron filings are brown, small, and magnetic: Copper sulfate crystals are blue, brittle, and not magnetic. After— The copper formed was reddish, solid, and not magnetic: Iron sulfide solution was colorless and not magnetic. Which statement supports that a chemical reaction took place? A. Changes in color occurred. B. A new substance was formed. C. A physical change in the iron occurred. D. The original substances were present after. 164. What do bubbles most likely indicate in a chemical reaction? A. phase change B. gas formation C. temperature change D. precipitate formation CHEMISTRY EOG QUESTIONS Page 40 of 59 165. A chemical reaction separates water into hydrogen gas and oxygen gas. Which of the following statements is true about the mass of the water and the combined mass of the two gases? A. The mass of the water is greater than the combined mass of the two gases. B. The combined mass of the two gases is much greater than the mass of the water. C. The combined mass of the two gases is the same as the mass of the water. D. The mass of the water is the same as double the combined mass of the two gases. 166. Since sodium chloride is classified as a compound, a sample of it contains A. atoms that are gases, liquids, and solids. B. more than one kind of atom. C. matter that cannot be reduced to atoms. D. a solution of atoms and molecules. 167. Which best describes a row of elements in the periodic table? A. column B. family C. group D. period 168. Hydrogen peroxide (H2O2) and water (H2O) both contain hydrogen (H) and oxygen (O). Why are they different compounds? A. Hydrogen peroxide contains one more oxygen than water. B. Hydrogen peroxide contains two more oxygens than water. C. Hydrogen peroxide contains one less oxygen than water. 169. Which best describes water? A. a compound B. an element C. a heterogeneous mixture D. a homogeneous mixture 170. Calcium carbonate A. molecules. B. elements. C. gases. D. solids. is considered a compound because it is made up of two or more CHEMISTRY EOG QUESTIONS Page 41 of 59 171. Which must be true if the number of atoms stays the same regardless of how they are arranged? A. Their total mass must change. B. Their total mass stays the same. C. An open system must have been used. 172. Which is true of any physical or chemical reaction? A. Mass increases. B. Mass decreases. C. Mass fluctuates. D. Mass is conserved. 173. When elements chemically combine with each other, what do they form? A. atoms B. electrons C. compounds 174. Which element is the least reactive? A. carbon B. helium C. hydrogen D. iodine 175. Which of these elements is most reactive? A. neon (Ne) B. carbon (C) C. sodium (Na) D. magnesium (Mg) CHEMISTRY EOG QUESTIONS Page 42 of 59 176. Which best supports the Law of Conservation of Mass? A. Atoms can be rearranged to keep the same mass. B. Atoms can be destroyed to make a new substance. C. Atoms can be rearranged to change their mass. 177. The formula for methane is CH4. How many different elements are in this substance? A. 1 B. 2 C. 4 D. 5 178. How are elements on the periodic table organized by their properties? A. in groups B. by masses C. in periods 179. How many chlorine (Cl) atoms would be needed to bond with one calcium (Ca) atom? A. 1 B. 2 C. 17 180. Which best describes the reactivity of metals when moving from left to right on the periodic table? A. They become less reactive. B. They become more reactive. C. The reactivity remains the same. D. The reactivity decreases, then increases. CHEMISTRY EOG QUESTIONS Page 43 of 59 181. Juan Carlos placed 35 grams of ice into a dry, 200gram container. The top of the container was attached tightly. When the ice was completely melted, the student massed the container with the liquid water. What mass of liquid water should be in the container? A. 35 grams B. 165 grams C. 200 grams D. 235 grams 182. Which are conserved during a chemical reaction? A. mass and atoms B. volume and mass C. atoms and molecules D. molecules and volume 183. Which is the most reactive group of nonmetals? A. Group 1 B. Group 5 C. Group 17 184. Which best describes how to balance the chemical equation shown below to support the law of conservation of mass? Mg + O2 → MgO A. Add the coefficient 2 before the Mg on both sides of the equation. B. Add the coefficient 2 before the O2 on the left side of the equation. C. Add the coefficient 2 before the Mg on the left side of the equation. D. Add the coefficient 2 before the MgO on the right side of the equation. 185. In which area of the periodic table would the elements with the highest density be found? A. the middle of the periodic table B. Group 1 on the periodic table C. the top of the group CHEMISTRY EOG QUESTIONS Page 44 of 59 186. The chart shows melting and boiling points of different substances. Melting and Boiling Points Substance Melting Point (°C) Boiling Point (°C) Alcohol –114 78.2 Formaldehyde –92 –19 Nicotine –79 247 Benzene 5.5 80 Nitroglycerine 13.5 250 Which substance freezes at the lowest temperature? A. Alcohol B. Nicotine C. Formaldehyde 187. Which of the following results when hydrogen and chlorine chemically bond to form hydrogen chloride? A. a mixture B. a solution C. a compound D. a precipitate 188. Which is the best evidence that a chemical change in matter has occurred? A. A solid melts. B. A gas is produced. C. Matter is destroyed during a chemical reaction. 189. A piece of paper has a mass of 17 grams. When the paper is burned, a chemical change occurs, and both smoke and ashes are produced. Based on the law of conservation of mass, which statement is true? A. The smoke has a mass of 17 grams. B. The ashes have a mass of 17 grams. C. The smoke and ashes have a combined mass of 17 grams. D. The smoke and the ashes have a combined mass greater than 17 grams. CHEMISTRY EOG QUESTIONS Page 45 of 59 190. Under certain conditions iron becomes iron oxide (rust). Identify what substances iron must be exposed to in order to become iron oxide. Explain what type of reaction occurs when these substances come in contact with iron. 191. This general chemical equation shows an example of energy availability in a theoretical reaction. Which statement is true about the equation? A. The equation is missing products. B. The equation is missing reactants. C. Energy was released. D. Energy was absorbed. 192. Which best describes a chemical reaction applying the law of conservation of mass? A. an equation which uses energy B. an equation which does not use energy C. a balanced equation in which the reactants and products are equal D. an unbalanced equation in which the reactants and products are unequal 193. When elements chemically combine, which best describes the resulting compound? A. It has different ratios of atoms. B. It has different types of matter. C. It has the same properties as the uncombined elements. D. It has different properties from the uncombined elements. 194. The best way to separate salt from water is with the use of A. oil. B. heat. C. a magnet. D. rubbing alcohol. CHEMISTRY EOG QUESTIONS Page 46 of 59 195. What is the relationship between elements with 6, 14, and 82 protons in their nuclei on the periodic table of elements? A. They are in the same group. B. They are in the same period. C. They have the same atomic mass. 196. Which process is most effective for separating sodium chloride from a saltwater solution? A. filtration B. evaporation C. magnetic separation D. chemical separation 197. What is the importance of a closed container in a chemical reaction? A. to observe the mass before and after the reaction occurs B. to keep any materials from interfering with the reaction C. to observe the loss of mass after the reaction occurs 198. Which ratio of reactants to products supports the law of conservation of mass? A. 2:1 because the mass of the reactants is halved during the reaction B. 1:2 because the mass of the reactants is doubled during the reaction C. 1:1 because the mass of the reactants before the reaction is equal to the mass of the products after the reaction D. 1:0 because the mass of the reactants is completely used up during the reaction so the products have no mass after the reaction 199. Which property of matter can easily be determined by looking at the periodic table? A. density B. solubility C. melting point D. chemical reactivity CHEMISTRY EOG QUESTIONS Page 47 of 59 200. What is the total number of oxygen atoms on the reactant side of the equation shown below? CH3COOH + NaHCO3 → CH3COONa + H2O + CO2 A. 2 B. 3 C. 5 D. 7 201. When a person chews, saliva from the mouth mixes with starches in food. These starches begin to turn into sugars. Changing starches into sugars is best described as A. a phase change. B. a cellular change. C. a physical change. D. a chemical change. 202. Mg(OH)2 is a compound. How many different elements are found in this compound? A. 1 B. 2 C. 3 203. Sodium (Na) and chlorine (Cl) combine to form sodium chloride (NaCl), which is commonly known as A. soap. B. vinegar. C. table salt. D. baking soda. 204. The chemical equation below shows reactants and products. Which statement is best supported by analyzing this equation? A. B. C. D. CHEMISTRY EOG QUESTIONS Page 48 of 59 205. Which occurs when a precipitate forms during a chemical reaction? A. color change B. production of a gas C. temperature change D. production of a solid 206. Where would a new highly reactive metal most likely be placed on the periodic table? A. right side B. left side C. middle D. top 207. Which best describes the classification of an element that is a shiny solid, conducts electricity, and has an atomic mass of approximately 108? A. It is a metal. B. It is synthetic. C. It is a metalloid. 208. Which of these is an element? A. KBr B. C. 2KCl D. 209. Which substance is a compound? A. salt B. sodium C. chlorine D. saltwater CHEMISTRY EOG QUESTIONS Page 49 of 59 210. Max recorded the notes below as he completed an experiment in science class. 20 grams of a solute was added to 100 grams of a liquid substance. The solute completely dissolved. The total mass of the resulting solution was 120 grams after the experiment was complete. Which best explains how the law of conservation of mass was demonstrated in the experiment? A. The solute completely dissolved in the liquid. B. The liquid was chemically changed by the addition of the solute. C. Some of the mass of the solute was lost during the experiment. D. The mass of the resulting solution was equal to the mass of the solute and liquid. 211. Examine the following chemical equation: This equation expresses which change? A. Two atoms combine to form one atom. B. Two atoms combine to form one molecule. C. Two elements combine to form a different element. D. Two elements combine to form two new elements. 212. Which is true of mass during a chemical reaction? A. Mass increases. B. Mass decreases. C. Mass remains the same. D. Mass depends on the chemicals involved. 213. Which best describes an element? A. It is the simplest form of matter. B. It can be changed into a compound. C. It can be broken down into simpler mixtures. D. It is composed of more than one type of atom. CHEMISTRY EOG QUESTIONS Page 50 of 59 214. Which is the best description of one particle of table salt (NaCl)? A. atom B. compound C. element 215. Which best explains the difference between an element and a compound? A. Elements cannot occur naturally, while compounds naturally occur. B. Elements have specific properties, while compounds do not have specific properties. C. Elements cannot be broken down, while compounds can because they join together in a specific pattern. D. Elements can be broken down, while compounds cannot because they are composed of two or more mixtures. 216. A chemistry teacher combines 20 grams of lemon juice with 25 grams of baking soda in a flask covered with a balloon. The flask and balloon have a combined mass of 105 grams. What is the mass of the entire setup after a reaction has occurred? A. 45 grams B. 150 grams C. 605 grams CHEMISTRY EOG QUESTIONS Page 51 of 59 217. Helium (He) is used to fill a round balloon at room temperature. Which best represents the arrangement of helium atoms inside the balloon at room temperature? A. B. C. D. CHEMISTRY EOG QUESTIONS Page 52 of 59 218. Which could best be separated into simpler substances by filtration and evaporation? A. atom B. mixture C. element D. compound 219. Which element would best be described as a brittle, nonconductive solid? A. calcium (Ca) B. sodium (Na) C. sulfur (S) D. thorium (Th) 220. An element is being studied in a lab. The element is nonreactive, but only has two valence electrons. Which element is being studied? A. neon B. helium C. oxygen 221. Which best describes the solid that forms when two liquids combine in a chemical reaction? A. gas B. energy C. precipitate 222. A student is given a mixture of granulated sugar and iron fillings. Identify two procedures the student could use to separate them, and explain how the different properties of sugar and iron allow each separation procedure to work. CHEMISTRY EOG QUESTIONS Page 53 of 59 223. Which chemical formula is an example of a compound? A. O2 B. 2Cl C. H2SO4 224. Elements in the same column of the Periodic Table of the Elements all A. have the same number of protons. B. share the same atomic structure. C. have similar physical characteristics. D. share the same number of neutrons. 225. The formula for glucose is C6H12O6. How many atoms are present in the glucose compound? A. 1 B. 6 C. 12 D. 24 226. The table below shows common compounds and their chemical formulas. Compounds and Chemical Formulas Compound Chemical Formula water H2O sodium chloride NaCl (table salt) glucose C6H12O6 sucrose C6H22O11 (table sugar) sodium bicarbonate NaHCO3 (baking soda) Which can best be concluded from this information? A. Some compounds contain only one element. B. All compounds contain the same number of elements. C. Elements combine in many ways to form different compounds. D. Elements combine in the same way to form different compounds. CHEMISTRY EOG QUESTIONS Page 54 of 59 227. Which will most likely occur during this reaction? reactants + energy → products A. physical change B. temperature change C. production of energy D. production of a precipitate 228. Which characteristic of an element determines its placement in the periodic table? A. mass B. size C. number of neutrons D. number of protons 229. How many more atoms does hydrogen peroxide (H2O2) have than water (H2O)? A. one B. two C. three D. four 230. Which best describes a compound? A. elements that are chemically combined B. elements that are physically combined C. elements that can be broken down into atoms D. elements that cannot be broken down into atoms 231. Which group contains elements with the most varied properties? A. noble gases B. alkali metals C. transition metals D. alkaline earth metals CHEMISTRY EOG QUESTIONS Page 55 of 59 232. Which represents the simplest form of the main component of all living organisms? A. the element carbon B. the compound carbon C. the element carbon monoxide D. the compound carbon monoxide 233. Two clear solutions are mixed together in a beaker. Which result would indicate a chemical reaction had occurred between these solutions? A. increase of volume in the beaker B. decrease of volume in the beaker C. increase in temperature of the beaker 234. An element, X, contains 14 protons, 15 neutrons, and 14 electrons. Which is most likely the same element as X? A. Element A: 13 protons, 15 neutrons, 14 electrons B. Element B: 14 protons, 14 neutrons, 14 electrons C. Element C: 15 protons, 14 neutrons, 15 electrons 235. Which is the correct way to balance the chemical equation shown below? Al + O2 → Al2O3 A. 2Al + O2 → Al2O3 B. 2Al + 3O2 → Al2O3 C. 4Al + 3O2 → Al2O3 D. 4Al + 3O2 → 2Al2O3 CHEMISTRY EOG QUESTIONS Page 56 of 59 236. When 5 grams of silver nitrate are added to a 50 gram solution of potassium chloride, 2 grams of silver chloride form in the solution as a precipitate. After the reaction, the total weight of the solution is 55 grams. Which evidence from the experiment supports the law of conservation of mass? A. The final weight of the product equals the weight of the reactants. B. The final weight of the product is less than the weight of the reactants. C. The weight of the precipitate is less than the amount of silver nitrate. D. The weight of the precipitate is greater than the amount of silver nitrate. 237. Which is classified as a compound? A. salt water B. helium gas C. sterling silver D. sulfur dioxide 238. Sugar is added to water, and the mixture is stirred. Which observation is evidence that the sugar dissolved in the water? A. Less sugar is visible. B. The water is cloudy. C. The sugar turned into crystals. D. Bubbles formed in the water. 239. Which particle type can be identified as being from a specific element? A. electron B. atom C. neutron D. proton 240. A scientist adds sodium acetate to boiling water until it is all dissolved. Once the solution starts to cool, it becomes solid crystals. Which is evidence that a chemical reaction has taken place? A. There is less liquid. B. There is more mass. C. A precipitate forms. CHEMISTRY EOG QUESTIONS Page 57 of 59 241. Sodium (Na), lithium (Li), and potassium (K) are grouped together in one column on the periodic table. Which property do they share? A. soft texture B. high reactivity C. semiconductivity D. gas at room temperature 242. The compound propane has three carbon atoms and eight hydrogen atoms. What is the chemical formula of propane? A. CH11 B. C3H8 C. C8H3 D. C11H 243. Hydrogen peroxide has one more oxygen atom than the compound water. What is the result of this extra oxygen atom? A. It makes peroxide more soluble than water. B. It makes peroxide more carbonated than water. C. It changes most of the properties of the compound. 244. Which is a property of metalloids? A. the ability to be pulled into long wires B. the ability to be hammered into sheets C. the ability to be a liquid at room temperature D. the ability to conduct electricity under certain conditions 245. What aspect of the missing elements did the periodic table help predict? A. electron clouds B. gravitational pull C. chemical properties CHEMISTRY EOG QUESTIONS Page 58 of 59 246. Which equation is balanced according to the Law of Conservation of Mass? A. NaCl + Mg → MgCl2 + Na B. 2NaCl + Mg → MgCl2 + Na C. 2NaCl + Mg → MgCl2 + 2Na 247. Which changes when gases condense to form liquids? A. physical mass B. physical state C. chemical reactivity D. chemical composition 248. Scientists can identify an element by looking at the structure of a single A. atom. B. neutron. C. molecule. D. electron. 249. Which describes only a physical change? A. baking a cake B. frying an egg C. burning a piece of toast D. squeezing the juice from fruit 250. A substance contains two components joined by physical means. Which best describes the substance? A. element B. compound C. mixture D. molecule CHEMISTRY EOG QUESTIONS Page 59 of 59