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OBJ 25 Quiz-LOCOM Multiple Choice Identify the choice that best completes the statement or answers the question. ____ 1. A student asks why the ashes from a fire have a much lower mass than the wood that was burned. Which is the correct answer to the student’s question? a. Gases are released into the air. b. Atoms in the wood are destroyed. c. Heat causes molecules to lose density. d. Water inside the wood solidifies. ____ 2. Students have two identical beakers with a mass of 20 grams each. The students pour a different liquid reactant into each beaker. The total mass of the two beakers with the reactants is 50 grams. Next, the students combine Reactant 1 and Reactant 2 into one of the beakers. A chemical reaction produces a product. If all of the reactants are consumed and no gases are produced, what is the total mass of the product and one beaker? a. 40 grams b. 30 grams c. 20 grams d. 70 grams ____ 3. In the equation below, 46 grams of sodium (Na) reacted with 36 grams of water (H2O). If 2 grams of hydrogen gas (H2) is produced by this reaction, what is the mass of sodium hydroxide (NaOH) produced? a. 10 grams b. 44 grams c. 80 grams d. 82 grams ____ 4. The reaction below shows potassium oxide being produced (KO2) by combining oxygen (O2) with potassium (K). The mass of potassium is 50 g and the mass of oxygen is 12 g. O2 + K KO2 What is the mass for the potassium oxide that was produced? a. 160 grams b. 62 grams c. 12 grams d. 50 grams ____ 5. A student observes a chemical reaction. Aluminum (Al) + Oxygen (O) yields Aluminum Oxide (Al2O3) She writes an equation that correctly displays the law of conservation of mass. Select the balanced equation below that she wrote about this chemical reaction. a. 2Al + 3O3 2Al2O3 c. Al + O2 Al2O3 b. 4Al + 2O2 3Al2O3 d. 4Al + 3O2 2Al2O3 ____ 6. A chemical equation is shown below. ____ Which substance is a reactant? a. Diydrogen Monoxide b. H2O 7. A chemical equation is shown below. 2H2O 2H2 + O2 c. Hydrogen d. Water 2H2O 2H2 + O2 Which of the following choices is the product of this chemical reaction? a. Hydrogen c. H2 b. Water d. Oxygen ____ 8. Examine the following chemical reaction Iron (Fe) reacts with Oxygen (O) to form iron oxide (FeO) which is commonly called rust. 2Fe + 3O2 2FeO3 Which chemical formula shown below is the product of this reaction? a. Iron (Fe) b. Iron Oxide c. 3O2 d. 2FeO3 ____ 9. A chemical equation is shown below. 2NaCl +2H2O Cl2 + H2 + 2NaOH Which substance is a reactant? a. NaCl b. Cl c. NaOH d. H2 ____ 10. A balanced chemical equation is shown below. 2PbO + 4NO2 + O2 2Pb(NO3) The product in this equation is...? a. O2 b. PbO c. NO2 d. Pb(NO3)2 ____ 11. Examine the four noble gases mentioned in the question below. Notice the elements in the far-right: Helium (He), Neon (Ne), Argon (Ar), and Krypton (Kr). Determine what group number they are in, and determine how many electron shells krypton has. a. Group 4, 6 electron shells c. Group 18, 4 electron shells b. Group 18, 7 electron shells d. Group 7, 8 electron shells ____ 12. Three elements are shaded in this periodic table: Nitrogen (N), Oxygen (O), and Fluorine (F) Which statement best describes all three shaded elements shown above? a. They all have the same atomic numbers and the same atomic mass. b. They are all in period 4, so they all have 4 electron shells. c. They all are metals in the second period. d. They are all in period 2, so they all have 2 electron shells. ____ 13. Look at the diagram below of one Boron (B) atom. Two-Part Question a) Based on the number of valence electrons, what group number is boron found in? b) Based on the number of electons shells, what period number is boron found in? a. Group 13, Period 5 c. Group 2, Period 13 b. Group 3, Period 3 d. Group 13, Period 2 ____ 14. A periodic table of the elements is shown below. Based on their locations on the periodic table, which two elements share the most similar chemical properties? a. He and Li b. H and Kn c. K and Ca d. Ne and Xe ____ 15. Use the Periodic Table above in question 14 to answer the following question. How many protons does the element Neon (Ne) have and how many electron shells does it have? a. 8 protons, and 10 electron shells c. 10 protons, and 2 electron shells b. 2 protons, and 8 electron shells d. 10 protons, and 18 electron shells