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Unit 4
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 39. Changing a subscript in a correctly written chemical formula
a. changes the number of moles represented by the formula.
b. changes the charges on the other ions in the compound.
c. changes the formula so that it no longer represents that compound.
d. has no effect on the formula.
____ 40. Which formula does NOT represent a molecule?
a. H2O (water)
c. CO2 (carbon dioxide)
b. NH3 (ammonia)
d. NaCl (table salt)
____ 41. What is the formula for zinc fluoride?
a. ZnF
b. ZnF2
c. Zn2F
d. Zn2F3
____ 42. What is the formula for the compound formed by calcium ions and chloride ions?
a. CaCl
c. CaCl3
b. Ca2Cl
d. CaCl2
____ 43. What is the formula for the compound formed by lead(II) ions and chromate ions?
a. PbCrO4
c. Pb2(CrO4)3
b. Pb2CrO4
d. Pb(CrO4)2
____ 44. What is the formula for aluminum sulfate?
a. AlSO4
b. Al2SO4
c. Al2(SO4)3
d. Al(SO4)3
____ 45. What is the formula for tin(IV) chromate?
a. Sn(CrO4)4
b. Sn2(CrO4)2
c. Sn2(CrO4)4
d. Sn(CrO4)2
____ 46. Name the compound Fe(NO2)2.
a. iron(II) nitrate
b. iron(II) nitrite
c. ferric nitrate
d. ferrous nitride
____ 47. Name the compound CuCO3.
a. copper(I) carbonate
b. cupric trioxycarbide
c. cuprous carbide
d. copper(II) carbonate
____ 48. What is the name of Sn3(PO4)4 under the Stock system of nomenclature?
a. stannous phosphate
c. tin(III) phosphate
b. tin(IV) phosphate
d. tin(II) phosphate
____ 49. What is the name of Cr2(SO4)3 under the Stock system of nomenclature?
a. chromium(II) sulfate
c. chromium(III) sulfate
b. chromic sulfate
d. chromous sulfate
____ 50. What is the metallic ion in copper(II) chloride?
a. Co2+
c. Cu2+
2–
b. Cl
d. Cl–
____ 51. Using the Stock system, name the compound PbO.
a. plumbous oxide
c. potassium oxide
b. lead oxide
d. lead(II) oxide
____ 52. Name the compound CF4.
a. calcium fluoride
b. carbon fluoride
c. carbon tetrafluoride
d. monocarbon quadrafluoride
____ 53. What is the formula for silicon dioxide?
a. SO2
b. SiO2
c. Si2O
d. S2O
____ 54. What is the formula for nitrogen trifluoride?
a. NiF3
b. NF3
c. N3F
d. Ni3F
____ 55. What is the formula for dinitrogen trioxide?
a. Ni2O3
b. NO3
c. N2O6
d. N2O3
____ 56. What is the formula for sulfur dichloride?
a. NaCl2
b. SCl2
c. S2Cl
d. S2Cl2
____ 57. A chemical reaction has NOT occurred if the products have
a. the same mass as the reactants.
b. less total bond energy than the reactants.
c. more total bond energy than the reactants.
d. the same chemical properties as the reactants.
____ 58. Which observation does NOT indicate that a chemical reaction has occurred?
a. formation of a precipitate
c. evolution of heat and light
b. production of a gas
d. change in total mass of substances
____ 59. In writing an equation that produces hydrogen gas, the correct representation of hydrogen gas is
a. H.
c. H2.
b. 2H.
d. OH.
____ 60. To balance a chemical equation, it may be necessary to adjust the
a. coefficients.
c. formulas of the products.
b. subscripts.
d. number of products.
____ 61. A chemical equation is balanced when the
a. coefficients of the reactants equal the coefficients of the products.
b. same number of each kind of atom appears in the reactants and in the products.
c. products and reactants are the same chemicals.
d. subscripts of the reactants equal the subscripts of the products.
____ 62. How would oxygen be represented in the formula equation for the reaction of methane and oxygen to yield
carbon dioxide and water?
a. oxygen
c. O2
b. O
d. O3
____ 63. When the equation Fe3O4 + Al  Al2O3 + Fe is correctly balanced, what is the coefficient of Fe?
a. 3
c. 6
b. 4
d. 9
____ 64. Which coefficients correctly balance the formula equation NH4NO2(s)  N2(g) + H2O(l)?
a. 1, 2, 2
c. 2, 1, 1
b. 1, 1, 2
d. 2, 2, 2
____ 65. Which coefficients correctly balance the formula equation CaO + H2O Ca(OH)2?
a. 2, 1, 2
b. 1, 2, 3
c. 1, 2, 1
d. 1, 1, 1
____ 66. After the first steps in writing an equation, the equation is balanced by
a. adjusting subscripts to the formula(s).
b. adjusting coefficients to the smallest whole-number ratio.
c. changing the products formed.
d. making the number of reactants equal to the number of products.
____ 67. What is the balanced equation for the combustion of sulfur?
a. S(s) + O2(g)  SO(g)
c. 2S(s) + 3O2(g)  SO3(s)
b. S(s) + O2(g)SO2(g)
d. S(s) + 2O2(g)  SO42–(aq)
____ 68. Which equation is NOT balanced?
a. 2H2 + O2  2H2O
b. 4H2 + 2O2 4H2O
c. H2 + H2 + O2  H2O + H2O
d. 2H2 + O2  H2O
____ 69. In what kind of reaction do two or more substances combine to form a new compound?
a. decomposition reaction
c. double-replacement reaction
b. ionic reaction
d. synthesis reaction
____ 70. The equation AX  A + X is the general equation for a
a. synthesis reaction.
c. combustion reaction.
b. decomposition reaction.
d. single-replacement reaction.
____ 71. In what kind of reaction does one element replace a similar element in a compound?
a. single-replacement reaction
c. decomposition reaction
b. double-replacement reaction
d. ionic reaction
____ 72. The equation AX + BY  AY + BX is the general equation for a
a. synthesis reaction.
c. single-replacement reaction.
b. decomposition reaction.
d. double-replacement reaction.
____ 73. The equation A + X  AX is the general equation for a(n)
a. combustion reaction.
c. synthesis reaction.
b. ionic reaction.
d. double-replacement reaction.
____ 74. In what kind of reaction does a single compound produce two or more simpler substances?
a. decomposition reaction
c. single-replacement reaction
b. synthesis reaction
d. ionic reaction
____ 75. The equation A + BX  AX + B is the general equation for a
a. double-replacement reaction.
c. single-replacement reaction.
b. decomposition reaction.
d. combustion reaction.
____ 76. In what kind of reaction do the ions of two compounds exchange places in aqueous solution to form two
new compounds?
a. synthesis reaction
c. decomposition reaction
b. double-replacement reaction
d. combustion reaction
____ 77. The reaction 2Mg(s) + O2(g)  2MgO(s) is a
a. synthesis reaction.
b. decomposition reaction.
c. single-replacement reaction.
d. double-replacement reaction.
____ 78. The reaction Mg(s) + 2HCl(aq)  H2(g) + MgCl2(aq) is a
a. composition reaction.
c. single-replacement reaction.
b. decomposition reaction.
d. double-replacement reaction.
____ 79. The reaction 2HgO(s)  2Hg(l) + O2(g) is a(n)
a. single-replacement reaction.
b. synthesis reaction.
c. ionic reaction.
d. decomposition reaction.
____ 80. The reaction Pb(NO3)2(aq) + 2KI(aq)  PbI2(s) + 2KNO3(aq) is a
a. double-replacement reaction.
c. decomposition reaction.
b. synthesis reaction.
d. combustion reaction.
____ 81. What is the balanced equation when aluminum reacts with copper(II) sulfate?
a. Al + Cu2S  Al2S + Cu
c. Al + CuSO4  AlSO4 + Cu
b. 2Al + 3CuSO4  Al2(SO4)3 + 3Cu
d. 2Al + Cu2SO4  Al2SO4 + 2Cu
____ 82. What is the name of a list of elements arranged according to the ease with which they undergo certain
chemical reactions?
a. reactivity list
c. activity series
b. reaction sequence
d. periodic list
____ 83. An element in the activity series can replace any element
a. in the periodic table.
b. below it on the list.
c. above it on the list.
d. in its group.
____ 84. Predict what happens when nickel is added to a solution of potassium chloride.
a. No reaction occurs.
c. Potassium nickel chloride forms.
b. Nickel chloride forms.
d. Hydrochloric acid forms.
____ 85. Magnesium bromide + chlorine yield
a. Mg and BrCl.
b. MgCl and Br2.
c. MgBrCl.
d. Mg(Cl)2 and Br2.
____ 86. Which reaction does NOT occur?
a. 2HF + Cl2  F2 + 2HCl
b. 2Na + ZnF2  2NaF + Zn
c. Fe + CuCl2  FeCl2 + Cu
d. 2HCl + Mg  MgCl2 + H2
____ 87. Which reaction can be predicted from the activity series?
a. 2Cl  Cl2
c. 2HCl + 2Na  2NaCl + H2
b. HCl + NaOH  NaCl + H2O
d. Cl2 2Cl
95.
When iron ore is processed to obtain iron, the reaction occurs as:
Fe2O3(s) + CO(g) → Fe(l) + CO2(g)
Which of the following is a balanced equation for this reaction?
a.
b.
c.
d.
98.
Fe2O3(s) + CO(g) → Fe(l) + CO2(g)
Fe2O3(s) + 3 CO(g) → 2 Fe(l) + 2 CO2(g)
Fe2O3(s) + 2 CO(g) → Fe(l) + 2 CO2(g)
Fe2O3(s) + 3 CO(g) → 2 Fe(l) + 3 CO2(g)
Given the balanced equation representing a reaction:
4Al(s) + 3O2(g)  2Al2O3(s)
Which type of chemical reaction is represented by this equation?
(1) double replacement
(2) single replacement
(3) substitution
(4) synthesis
99. Why can an increase in temperature lead to more effective collisions between reactant particles and
an increase in the rate of a chemical reaction?
(1) The activation energy of the reaction increases.
(2) The activation energy of the reaction decreases.
(3) The number of molecules with sufficient energy to react increases.
(4) The number of molecules with sufficient energy to react decreases.
1.A chemical formula for a molecular compound represents the composition of
____
____
____
____
a. a molecule.
c. the ions that make up the compound.
b. an atom.
d. the crystal lattice.
2. What is the formula for the compound formed by calcium ions and chloride ions?
a. CaCl
c. CaCl3
b. Ca2Cl
d. CaCl2
3. What is the formula for barium hydroxide?
a. BaOH
c. Ba(OH)2
b. BaOH2
d. Ba(OH)
4. Name the compound KClO3.
a. potassium chloride
c. potassium chlorate
b. potassium trioxychlorite
d. hypochlorite
5. Name the compound Fe(NO2)2.
a. iron(II) nitrate
c. ferric nitrate
b. iron(II) nitrite
____
____
____
____
d. ferrous nitride
6. What is the metallic ion in copper(II) chloride?
a. Co2+
c. Cu2+
b. Cl2–
d. Cl–
7. Name the compound CF4.
a. calcium fluoride
c. carbon tetrafluoride
b. carbon fluoride
d. monocarbon quadrafluoride
8. Name the compound SO3.
a. sulfur trioxide
c. selenium trioxide
b. silver trioxide
d. sodium trioxide
9. Name the compound N2O3.
a. dinitrogen oxide
c. nitric oxide
b. nitrogen trioxide
d. dinitrogen trioxide
____ 10. What is the formula for silicon dioxide?
a. SO2
c. Si2O
b. SiO2
d. S2O
____ 11. What is the formula for carbon disulfide?
a. CaS2
c. S2C
b. CS2
d. SC2
____ 12. What is the sum of the atomic masses of all the atoms in a formula for a compound?
a. molecular mass
c. atomic mass
b. formula mass
d. actual mass
____ 13. What is the formula mass of ethyl alcohol, C2H5OH?
a. 30.328 amu
c. 45.061 amu
b. 33.271 amu
d. 46.069 amu
____ 14. The molar mass of CCl4 is 153.81 g/mol. How many grams of CCl4 are needed to have 5.000 mol?
a. 5 g
c. 769.0 g
b. 30.76 g
d. 796.05 g
____ 15. The molar mass of CS2 is 76.14 g/mol. How many grams of CS2 are present in 10.00 mol?
a. 0.13 g
c. 10.00 g
b. 7.614 g
d. 761.4 g
____ 16. How many OH– ions are present in 3.00 mol of Ca(OH)2?
a. 3.00
c. 3.61 1024
b. 6.00
d. 2.06 1023
____ 17. How many Mg2+ ions are found in 1.00 mol of MgO?
a. 3.01 1023
c. 12.04 1023
b. 6.02 1023
d. 6.02 1025
____ 18. If 0.500 mol of Na+ combines with 0.500 mol of Cl– to form NaCl, how many formula units of NaCl are
present?
a. 3.01 1023
c. 6.02 1024
b. 6.02 1023
d. 1
____ 19. What is the percentage composition of chlorine in NaCl?
a. 35.45%
c. 60.7%
b. 50%
d. 64.5%
____ 20. What is the percentage composition of oxygen in H2O?
a. 15.99%
c. 88.8%
b. 33%
d. 99.8%
____ 21. The empirical formula for a compound shows the symbols of the elements with subscripts indicating the
a. actual numbers of atoms in a molecule.
b. number of moles of the compound in 100 g.
c. smallest whole-number ratio of the atoms.
d. atomic masses of each element.
____ 22. The empirical formula may not represent the actual composition of a unit of a(n)
a. ionic compound.
c. atom.
b. molecular compound.
d. crystal.
____ 23. What is the empirical formula for a compound that is 53.3% O and 46.7% Si?
a. SiO
c. Si2O
b. SiO2
d. Si2O3
____ 24. What is the empirical formula for a compound that is 36.1% Ca and 63.9% Cl?
a. CaCl
c. CaCl2
b. Ca2Cl
d. Ca2Cl2
____ 25. A compound contains 27.3 g of C and 72.7 g of O. What is the empirical formula for this compound?
a. CO
c. C2O
b. CO2
d. C2O4
Standard Chemistry do not study 26-31
____ 26. The empirical formula and the formula mass of a compound are needed to determine the compound's
a. molecular formula.
c. lattice structure.
b. bond energy.
d. toxicity.
____ 27. Of the following molecular formulas for hydrocarbons, which is an empirical formula?
a. CH4
c. C3H6
b. C2H2
d. C4H10
____ 28. A compound's empirical formula is C2H5. If the formula mass is 58 amu, what is the molecular formula?
a. C3H6
c. C5H8
b. C4H10
d. C5H15
____ 29. A compound's empirical formula is CH. If the formula mass is 26 amu, what is the molecular formula?
a. C2H2
c. CH4
b. CH3
d. C4H
____ 30. A compound's empirical formula is HO. If the formula mass is 34 amu, what is the molecular formula?
a. H2O
c. HO3
b. H2O2
d. H2O3
Short Answer
31. Explain the term empirical formula. What is the empirical formula of strontium bromide, SrBr2?
Problem
32. The molar mass of aluminum is 26.98 g/mol and the molar mass of fluorine is 19.00 g/mol. Calculate the
molar mass of aluminum trifluoride, AlF3.
33. The molar mass of copper is 63.55 g/mol, the molar mass of sulfur is 32.07 g/mol, and the molar mass of
oxygen is 16.00 g/mol. Calculate the molar mass of copper(II) sulfate, CuSO4.
34. The molar mass of iron is 55.85 g/mol, the molar mass of silicon is 28.09 g/mol, and the molar mass of
oxygen is 16.00 g/mol. Calculate the molar mass of iron(II) silicate, Fe2SiO4.
35. The molar mass of aluminum is 26.98 g/mol and the molar mass of oxygen is 16.00 g/mol. Determine the
molar mass of Al2O3.