Name _________________KEY____________________ Date of final _______/________ Semester I Review sheet Filtration, chromatography, distillation, evaporation, and decanting are PHYSICAL separation methods. 1. Which of the above methods would you select to separate: a. The sand from a sand and water mixture evaporation, decantation or filtration_ b. The salt from a mixture of salt and water ___evaporation___ c. The dyes from a mixture of dyes in ink? _chromatography_ d. The H2 and the O2 from a sample of H2O? _none of the above_ 2. What types of matter are classified as pure substances? Elements & compounds 3. Are pure substances homogeneous? 4. What is a solution? 5. Are solutions homogeneous? _____Yes_________ _homogeneous mixture_ _______Yes________ 6. What type of matter does not have uniform properties throughout? Heterogeneous mixtures 7. Draw the flow map to show how we classify matter. Use the following options to identify the samples described in questions 7-14. A. Element C. Compound B. Homogeneous mixture D. Heterogeneous mixture 8. Sample is a liquid. ____B____ Sample appears uniform throughout. Sample can be separated into simpler components using distillation. 9. Sample has uniform composition. ____C____ The compositions of all samples of this matter are identical. Sample contains more than one type of atom. 10. Sample is homogeneous. ____B____ Different samples of this type of matter can vary in their composition. 11. Sample is homogeneous. ____A____ Sample cannot be broken into simpler components using either chemical or physical methods 12. Sample may be separated into simpler components using filtration. ____D____ Some portions of the sample are liquid but other portions are solid. 13. Sample has uniform composition. ____C____ Sample has definite composition. Sample can be separated into simpler components only by chemical reaction. 14. Sample has uniform composition. ___B____ Sample has variable, NOT definite composition. Sample can be separated into simpler components using chromatography. 15. Sample is homogeneous. ____B____ Sample contains more than one type of atom but they are not bonded to each other. 16. Mark an X in the column(s) that satisfy the description. You may select more than one. Description Solid Capable of flowing Liquid Gas X X Compressible X Greatest distance between particles X Most orderly particle arrangement X Slowest Particle Motion X Fixed volume X X Highest energy X Occupies the volume of the container X Most rapid particle motion X 17. Determine if the following changes are physical changes or chemical changes. Mark an X in the appropriate column. Change Physical Change Chemical Change Water Boils X Iron rusts X Sodium Chloride dissolves in water X Wax melts X Wood Burns X Methane gas combusts X Dry ice sublimes X CaS is formed from Ca and S X Magnesium reacts with hydrochloric acid X 18. Extensive property Intensive property Definition A property that is proportional to the amount of sample present. A physical property that does NOT depend on the amount of sample present. Mass, volume, shape/size. Density, odor, luster, malleability, conductivity, color, reactivity, hardness. Examples 19. Determine if the following properties are Extensive or Intensive. Mark an X in the appropriate column. Property Extensive Property Intensive Property Color Mass X X Density Volume 20. X X Conductivity X Malleability X Reactivity X What information does the atomic number of an element provide? The atomic number is the number of protons in the nucleus of an atom of that element. If it is an atom (not an ion), it is also the number of electrons. 21. What does it mean to say that two or more atoms are isotopes of each other? They are the same element (same number of protons), but have a different mass number due to a change in the number of neutrons in the nucleus. 22. What do magnesium-24 and magnesium-25 have in common? How are these isotopes different? Same number of protons A different mass number due to a different number of neutrons. 23. Do all chlorine atoms weigh 35.453 amus? _____No_____ Explain. 35.453 is the weighted average of all of the isotopes of chlorine. Some isotopes are more abundant than others. 24. What information does the atomic mass provide? The weighted average of all of the isotopes of the element. 25. An element has three isotopes. Given the abundances and relative masses, calculate the average atomic mass and determine (from the periodic table) which element it is. 1. Convert % to decimal by moving the decimal point 2 places to the left. 2. Multiply by the amu. 3. Add the products. 0.005% 234.0409 amu 234.0409 X .00005 = 0.01170205 0.720% 235.0439 amu 235.0439 X .00720 = 1.692316 99.275% 238.0508 amu 238.0508 X .99275 = 236.3250 + ___________ Atomic mass: ____238.0290 amu_____ Element: _______Uranium_________ 26. Copper has 2 isotopes: Copper-63 (62.93 amu) and Copper-65 (64.927 amu). Their abundances are 69.17% and 30.83%, respectively. Calculate the average atomic mass for Copper. **Same instructions as #24 .6917 X 62.93 = 43.53 .3083 X 64.927 = 20.017 43.53 + 20.017 = 63.55 amu 27. Why is sodium placed before magnesium on the periodic table? The periodic table is arranged by increasing atomic number (number of protons). Sodium has 11 protons and Magnesium has 12 protons. 28. Why is Tellurium placed before Iodine on the periodic table? The periodic table is arranged by increasing atomic number (number of protons). Tellurium has 52 protons and Iodine has 53 protons. 29. Why do all of the elements in group 17 have similar chemical properties? They have the same number of valence electrons. 30. How many valence electrons are in a Halogen? How do get the number? 7. From the group number. 31. What charge will an Alkali metal have when it forms an ion? Why? 1+ because it loses one valence electron. 32. Does a member of the Nitrogen family form a negative ion or a positive ion? What charge will the ion have? What do we call this ion? Negative 3Anion 33. Does an alkali Earth metal gain or lose electrons when it forms an ion? What charge will the ion have? What do we call this ion? Lose 2+ Cation 34. a. Element Q is in the Boron family. Draw the dot structure of an atom of Q. Q b. Draw the dot structure of an ion of Q. Q3+ 35. Element X is an Alkaline Earth metal a. Draw the dot structure of an atom of X. X b. Draw the dot structure of an ion of X. X2+ 36. How many valence electrons do transition metals have? _2__ 37. Name the two series that make up the Inner Transition Metals. _____lanthanide_______ and _____actinide______ 38. These are Dalton’s Postulate regarding the nature of the atom: 1. All matter consists of indivisible particles called atoms. 2. Atoms of the same element have the same shape and mass. 3. Atoms cannot be created or destroyed. 4. Atoms of different elements may combine with each other in fixed, simple, whole number ratios to form compound atoms. Which of these postulates are consistent with the modern concept of the atom? 3&4 For those that are no longer considered true, explain WHY they are no longer considered to be true. 1: Atoms are not indivisible, they are made up of smaller subatomic particles. 2: Isotopes are atoms of the same element with different masses. 39. The atom hasn’t changed over time, but our understanding of it has. Sequence the descriptions of the atom below in the order that best represents the order of increasing understanding. a. b. c. d. II, IV, I, III II, I, IV, III III, I, IV, II IV, II, III, I 40. What were the two major conclusions drawn from Rutherford’s Gold Foil experiment? 1. The nucleus is small, dense and positively charged. 2. Most of an atom’s volume is empty space. 41. What was JJ Thomson’s contribution to chemistry and what was his model? Plum Pudding Model Electrons were negative particles (plums) stuck in the positive ‘pudding’. 42. What was Chadwick’s contribution to chemistry and what was his model? Discovered the neutron, located in the nucleus with the proton. 43. Identify the properties below as being more typical of Metals or NonMetals. Mark an X in the appropriate column. Property Ductility Relatively few valence electrons Metal X X X Hold valence electrons tightly X Gain electrons when forming ions X Brittle Form bonds with others of their kind due to a delocalized “Sea of Electrons” X X Non-conductors of electricity Form positive ions Heat conductors Malleable Lustrous May have an electron configuration that ends in a “d” sublevel Form bonds with others of their kind by sharing electron pairs Non-metal X X X X X X 44. If electronegativity values are not available, how do decide if a compound will bond ionically or covalently? Placement on the periodic table. 45. What causes the bond between two metals? Attraction of cations to the sea of delocalized electrons. 46. Determine if the statements listed in the table below are referring to ionic or molecular substances. Mark and X in the appropriate column. Ionic Molecular Statement Substance Substance Electrons are shared Electrons are transferred X X Made up of atoms X Conduct electricity when melted or dissolved X Made up of ions X High melting points X Contain only non-metals X Low boiling point X Hard but brittle X Most are solids at room temperature X Representative particle is the molecule. Representative particle is the formula unit. 47. a. X X An element Q, forms the following compounds: QCl2, QO, and Q3N2. Is Q a metal or a non-metal? ____metal______ b. To which family does Q belong? ___alkaline earth_ c. How many valence electrons are in an atom of Q _______2_______ d. What is the charge on the ion that Q forms? ______2+_______ e. Will Q’s last electron be placed in an s, p, or d sublevel? _____s_______ f. Draw the dot structure of an atom of Q. Q 48. a. An element X, forms the following compounds: K3X and Sr3X2. Is X a metal or a non-metal? ___non-metal____ b. To which family does X belong? ___Nitrogen_______ c. How many valence electrons are in an atom of X _______5_______ d. What is the charge on the ion that X forms? _____3-_________ e. Will X’s last electron be placed in an s, p, or d sublevel? ______p______ f. Draw the dot structure of an ion of X. X3- 49. Using dots and arrows show how a compound forms between Calcium and Chlorine. Ca Cl Cl When this process occurs, a. Which atoms give up electrons? ____Ca____ b. Which atom gain electrons ____Cl_____ c. What is the formula for the compound that forms __CaCl2____ d. What charge is on the calcium ions in the compound that forms? ___2+_____ e. What charge is on the chloride ions formed? ___1-_____ f. What charge does the compound have? ____0_____ g. How many total ions are in one formula unit of the compounds? ____3_____ 50. What is the name given to the electrons in the highest occupied energy level of an atom? a. orbital electrons c. anions b. valence electrons d. cations 51. What is the charge on the strontium ion? How do we find it? Based on Strontium’s location on the periodic table, it is a metal with 2 valence electrons. When it loses those 2 valence electrons it will have a 2+ charge. 52. a. 0 What is the charge on the cation in the ionic compound sodium sulfide? c. 2+ b. 1+ d. 3+ 53. Which of the following occurs in an ionic bond? a. Oppositely charged ions attract. b. Two atoms share two electrons. c. Two atoms share more than two electrons. d. Like-charged ions attract. 54. What is the net charge of the ionic compound calcium fluoride? a. 2– c. 0 b. 1– d. 1+ 55. How many valence electrons are transferred from the nitrogen atom to potassium in the formation of the compound potassium nitride? a. 0 c. 2 b. 1 d. 3 56. How many valence electrons are transferred from the calcium atom to iodine in the formation of the compound calcium iodide? a. 0 c. 2 b. 1 57. d. 3 Which of the following is a molecular formula? a. MgS b. PCl5 c. Cr2O3 d. AgBr 58. In the tables below, identify the type of compound as follows: M = molecular compound BS = binary salt TS = ternary salt Substance Name Type of Substance Formula Carbon monoxide M CO Potassium oxide BS Dicarbon pentahydride M C2H5 Sodium bicarbonate TS Na1+ HCO31- NaHCO3 Copper II bromide BS Cu2+ Br- CuBr2 Lithium acetate TS Li1+ C2H3O2 LiC2H3O2 Ammonium sulfite TS Strontium nitrite TS Sr2+ NO2- Iron III arsenate TS Fe3+ AsO43- K1+ O2- NH41+ SO32- K 2O (NH4)2SO3 Sr(NO2)2 Fe(AsO4) Substance Formula Type of Substance Name N2O2 M Dinitrogen dioxide (NH4)3N BS Ammonium nitride PbF3 BS Lead III fluoride Mn(ClO)2 TS Manganese II hypochlorite C2N M Dicarbon mononitride Ca(CN)2 TS Calcium cyanide CuCl BS Copper I chloride Ni2S BS Nickel I sulfide BaF2 BS Barium fluoride N2O5 M Dinitrogen pentaoxide 59. Draw the molecular Lewis dot structure for the following compounds and determine the shape of the molecule. Compound Dot Structure F F B BF3 Shape name Trigonal planar F Tetrahedral H CH4 H C H H Bent H2S H S H Trigonal pyramidal H NH3 N H 60. H Fill in the table below Noble Gas Element or Ion of element Electron Configuration P 1s22s22p63s23p3 [Ne] 3s23p3 B 1s22s22p1 [He] 2s22p1 Cl 1s22s22p63s23p5 [Ne] 3s23p5 S2- 1s22s22p63s23p6 [Ne] 3s23p6 K+ 1s22s22p63s23p64s1 [Ar] 4s1 Configuration 61. Calculate the wavelength of light (in meters) that has a frequency of 6.19 X 1014 -1 sec . C=f 62. 3.0 X 108 m/s = x 6.19 X 1014 sec-1 What is the energy, in Joules, of a photon that has a frequency of 4.23 X 1014 Hz? E = hf 63. 64. = 4.85 X 10-7 m 6.626 X 10-34 x 4.23 X 1014 E= 2.80 X 10-19 J Calculate the energy of a photon of light if the wavelength is 4.25 X 10-7m. C=f 3.0 X 108 = 4.25 X 10-7 x f f= 7.06 X 1014 Hz E= hf E = 6.626 X 10-34 X 7.06 X 1014 E = 4.68 X 10-19 J Is the energy of light directly or inversely proportional to frequency? Directly 65. Is the energy of light directly or inversely proportional to wavelength? Inversely 66. Is the frequency of light directly or inversely proportional to its wavelength? Inversely 67. An atom has the following electron configuration: 1s2 2s2 2p6 3s2 3p4 a. What element is this? _____Sulfur_________ b. How many valence electrons are in this atom? ____________6__________ c. How many unpaired electrons are in this atom? ____________2__________ d. What is the electron configuration of the ion of this atom? ___1s22s22p63s23p6_____ 68. Which is more important when determining the periodic trends that occur when comparing elements in the same group or family, addition of energy levels (shielding) or nuclear charge? Why? The addition of energy levels (shielding). This increases the atomic radius and weakens that attraction between the nucleus and valence electrons. 69. Which is more important when determining the periodic trends that occur when comparing element in the same period, addition of energy levels (shielding) or nuclear charge? Why? The nuclear charge determines the trends across a period. As you go across, additional protons in the nucleus increase the ‘power’ of the nucleus to attract the valence electrons and also decreases the size of the atom. 70. As you go down group 2, do the following properties increase, or decrease? a. Atomic radius _______I________ b. Electronegativity _______D________ c. Ionization energy _______D________ d. Metallic character ________I_______ e. Non-metallic character ________D_______ 71. As you go across period 3, do the following properties increase, or decrease? a. Atomic radius ______D________ b. Electronegativity ______I________ c. Ionization energy ______I________ d. Metallic character ______D________ e. Non-metallic character ______I________ 72. Record these measurements to the correct number of significant figures. **What you can read from the LINES on the instrument, plus one more place as an estimate!! 21.6OC 4.50 cm 20.38 mL 46 mL 73. Perform the following operations. Record your answers to the correct number of significant figures. 3.001 + 8.6 ____11.6_______ 0.0010 - 3.0000___-2.9990______ 324.1 + 1.032 ___325.1______ 62000. + 3200. __65200._______ 3240 - 0.379 ___3240_______ 3496 2.1 ____1700_______ 3.1 500 ____0.006______ 6.1 7.81 0.002 X 44 2.2 X 5.00 _____.78_________ ______0.09_______ ______11________ 74. These numbers are in scientific notation. Put them in standard notation. Think carefully about when to place a decimal point at the end of a number. _____.300______ _____20.1_______ 3.00 X 10-1 2.01 X 101 ______.0001____ 1 X 10-4 _____60000_2SF_ 6.0 X 104 ______875______ 8.75 X 102 ___830.001_____ 8.30001 X 102 _____770_______ 7.7 X 102 ____.00045_____ 4.5 X 10-4 _____.006401___ 6.401 X 10-3 ____7050_______ 7.05 X 103 75. These numbers are in standard notation. Put them in scientific notation. Think carefully about when to place a decimal point at the end of a number. 0.000 000 000 154 __1.54 X 10-10__ 0.00418 ____4.18 X 10-3_____ 3.0800____3.0800 X 100____ 709 __7.09 X 102_____ 91,600 ____9.16 X 104___ 0.00003005 ___3.005 X 10-5___ 250. ___2.50 X 102______ 780,000,000 ___7.8 X 108_____ Convert the following: 76. 7.9 X 103g = ________ g 7.9 X 103 g / 1 g__ / 106g 77. How many meters are in 67 dam? 67 dam / / 78. = 7.9 X 10-3 g 101 m 1 dam = 6.7 X 102 m 2,470 kL = _________ L 2470 kL / 103 L = 2.47 X 106 L / 1 kL 79. Convert 7.45 X 10-3dsec to Msec 7.45 X 10-3 dsec / 1 sec / 1 Msec = 7.45 X 10-10 Msec / 101 dsec / 106 sec 80. Three students made multiple massings of a copper cylinder, each using a different balance. The correct mass of the cylinder is 68.32 g. Mass of Cylinder (g) Sarah John Luke Massing 1 68.10 68.45 68.95 Massing 2 68.94 68.39 68.91 Massing 3 67.83 68.42 68.89 Massing 4 68.47 68.41 68.93 Describe the representation of the accuracy and precision of the data collected by the three students Sarah: Not Accurate, Not Precise (Measurements are all over the place.) John: Is Accurate, Is Precise (Very close to each other, and to the true amount.) Luke: Is Precise, Not Accurate (Not close to true amount, but are close to each other.) 81. Three different people weighed these blocks on the same balance and they each obtained a measurement of 7.98 g. The mass of the blocks was 5.00 g. Describe the representation of the accuracy and precision of the data collected by the three students The measurements are precise because they are all the same. The measurements are not accurate, because they are not close to the actual value.