Study Guide Spring 2012

Study Guide Spring 2012

STUDY GUIDE SPRING 2012

Multiple Choice

Identify the letter of the choice that best completes the statement or answers the question.

____1.The number of atoms in a mole of any pure substance is called

a. / its atomic number. / c. / its mass number.
b. / Avogadro’s number. / d. / its gram-atomic number.

____2.What can be said about 1 mol Ag and 1 mol Au?

a. / They are equal in mass.
b. / They contain the same number of atoms.
c. / Their molar masses are equal.
d. / They have the same atomic mass.

____3.An Avogadro’s number of any element is equivalent to

a. / the atomic number of that element. / c. / 6.022  1023 particles.
b. / the mass number of that element. / d. / 12 g of that element.

____4.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. / 1.00

____5.Using a periodic table, what is the average atomic mass of zinc?

a. / 69.723 amu / c. / 63.546 amu
b. / 58.693 amu / d. / 65.39 amu

____6.The atomic mass of hydrogen is 1.008 amu. The reason that this value is not a whole number is that

a. / hydrogen only exists as a diatomic molecule.
b. / the mass of hydrogen is the sum of the masses of the protons and electrons in the atom.
c. / the mass of a proton is not exactly equal to 1 amu.
d. / hydrogen has more than one isotope.

____7.A chemical formula includes the symbols of the elements in the compound and subscripts that indicate

a. / the number of formula units present.
b. / the number of atoms or ions of each type.
c. / the formula mass.
d. / the charges on the elements or ions.

____8.How many atoms of fluorine are in a molecule of carbon tetrafluoride, CF4?

a. / 1 / c. / 4
b. / 2 / d. / 5

____9.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c. / changes the formula so that it no longer represents that compound.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.

____10.A formula that shows the simplest whole-number ratio of the atoms in a compound is the

a. / molecular formula. / c. / structural formula.
b. / ideal formula. / d. / empirical formula.

____11.The molar mass of an element is the mass of one

a. / atom of the element. / c. / gram of the element.
b. / liter of the element. / d. / mole of the element.

____12.To determine the molar mass of an element, one must know the element’s

a. / Avogadro number. / c. / number of isotopes.
b. / atomic number. / d. / average atomic mass.

____13.What is the molar mass of magnesium?

a. / 12.00 g / c. / 24.305 g
b. / 26.982 g / d. / 22.990 g

____14.What is the empirical formula for a compound that is 31.9%potassium, 28.9%chlorine, and 39.2%oxygen?

a. / KClO2 / c. / K2Cl2O3
b. / KClO3 / d. / K2Cl2O5

____15.What is the empirical formula for a compound that is 43.6%phosphorus and 56.4%oxygen?

a. / P3O7 / c. / P2O3
b. / PO3 / d. / P2O5

____16.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

____17.A compound contains 259.2 g of F and 40.8 g of C. What is the empirical formula for this compound?

a. / CF4 / c. / CF
b. / C4F / d. / CF2

____18.A compound contains 64 g of O and 4 g of H. What is the empirical formula for this compound?

a. / H2O / c. / H4O4
b. / H2O2 / d. / HO

____19.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

____20.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

____21.To find the molecular formula from the empirical formula, one must determine the compound’s

a. / density. / c. / structural formula.
b. / formula mass. / d. / crystal lattice.

____22.A molecular compound has the empirical formula XY3. Which of the following is a possible molecular formula?

a. / X2Y3 / c. / X2Y5
b. / XY4 / d. / X2Y6

____23.The molecular formula for vitamin C is C6H8O6. What is the empirical formula?

a. / CHO / c. / C3H4O3
b. / CH2O / d. / C2H4O2

____24.A compound’s empirical formula is NO2. If the formula mass is 92 amu, what is the molecular formula?

a. / NO / c. / NO2
b. / N2O2 / d. / N2O4

____25.What is the percentage composition of CF4?

a. / 20% C, 80% F / c. / 16.8% C, 83.2% F
b. / 13.6% C, 86.4% F / d. / 81% C, 19% F

____26.What is the percentage composition of CuCl2?

a. / 33% Cu, 66% Cl / c. / 65.50% Cu, 34.50% Cl
b. / 50% Cu, 50% Cl / d. / 47.267% Cu, 52.733% Cl

____27.The percentage of sulfur in SO2 is about 50%. What is the percentage of oxygen in this compound?

a. / 25% / c. / 75%
b. / 50% / d. / 90%

____28.What is the percentage of OH– in Ca(OH)2?

a. / 45.9% / c. / 75%
b. / 66.6% / d. / 90.1%

____29.Knowledge about what products are produced in a chemical reaction is obtained by

a. / inspecting the chemical equation. / c. / laboratory analysis.
b. / balancing the chemical equation. / d. / writing a word equation.

____30.A chemical reaction has NOT occurred if the products have

a. / the same mass as the reactants.
b. / more energy than the reactants.
c. / less energy than the reactants.
d. / the same chemical properties as the reactants.

____31.Which observation does NOT indicate that a chemical reaction has occurred?

a. / formation of a precipitate / c. / evolution of energy
b. / production of a gas / d. / change in total mass of substances

____32.The word equation solid carbon + oxygen gas  carbon dioxide gas + energy, represents a chemical reaction because

a. / the reaction releases energy.
b. / CO2 has chemical properties that differ from those of C and O.
c. / the reaction absorbs energy.
d. / CO2 is a gas and carbon is a crystal.

____33.In the unbalanced formula equation CO + O2 CO2 + energy, energy

a. / is absorbed. / c. / is released.
b. / can be considered a reactant. / d. / Both (a) and (b)

____34.The word equation for the formula equation shown is

C2H5OH + O2 CO2 + H2O + energy

a. / carbon dioxide + water  ethanol + oxygen + energy.
b. / ethanol + oxygen  carbon dioxide + water + energy.
c. / ethanol + oxygen + energy  carbon dioxide + water.
d. / ethanol + oxygen + energy  carbon dioxide + water + energy.

____35.The state of matter for a reactant or a product in a chemical equation is indicated by a

a. / coefficient before the formula. / c. / symbol after the formula.
b. / subscript after the formula. / d. / superscript after the formula.

____36.The reaction, C2H5OH + 3O2 2CO2 + 3H2O, will occur most rapidly if

a. / C2H5OH is a liquid and O2 is a liquid. / c. / CO2 is a gas and H2O is a liquid.
b. / C2H5OH and O2 are in close contact. / d. / CO2 is a gas and H2O is a gas.

____37.An insoluble solid produced by a chemical reaction in solution is called

a. / a precipitate. / c. / a molecule.
b. / a reactant. / d. / the mass of the product.

____38.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

____39.The products of the reaction, C2H5OH + 3O2 2CO2 + 3H2O have the same _____ as the reactants.

a. / atoms. / c. / molecules.
b. / coefficients. / d. / subscripts.

____40.After the correct formula for a reactant in an equation has been written, the

a. / subscripts are adjusted to balance the equation.
b. / formula should not be changed.
c. / same formula must appear as the product.
d. / symbols in the formula must not appear on the product side of the equation.

____41.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.

____42.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.

____43.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.

____44.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

____45.Which coefficients correctly balance the formula equation CaCO3(s)CaO(s)+CO2(g)?

a. / 1, 1, 1 / c. / 2, 6, 3
b. / 1, 3, 1 / d. / 3, 1, 2

____46.Which equation is NOT balanced?

a. / 2H2 + O2 2H2O / c. / H2 + H2 + O2 H2O + H2O
b. / 4H2 + 2O2 4H2O / d. / 2H2 + O2 H2O

____47.Which coefficients correctly balance the formula equation NH4NO2N2+H2O?

a. / 1, 2, 2 / c. / 2, 1, 1
b. / 1, 1, 2 / d. / 2, 2, 2

____48.Which coefficients correctly balance the formula equation CaO+H2OCa(OH)2?

a. / 2, 1, 2 / c. / 1, 2, 1
b. / 1, 2, 3 / d. / 1, 1, 1

____49.Which coefficients correctly balance the formula equation

Zn(OH)2 + CH3COOH  Zn(CH3COO)2 + H2O?

a. / 1, 2, 1, 1 / c. / 1, 2, 1, 2
b. / 2, 1, 2, 1 / d. / 2, 1, 1, 2

____50.A reaction of a hydrocarbon, in which carbon dioxide and water are produced, is classified as a

a. / decomposition reaction. / c. / double-displacement reaction.
b. / combustion reaction. / d. / synthesis reaction.

____51.In what kind of reaction do two or more substances combine to form a new compound?

a. / decomposition reaction / c. / double-displacement reaction
b. / ionic reaction / d. / synthesis reaction

____52.The equation A + X  AX is the general equation for a(n)

a. / combustion reaction. / c. / synthesis reaction.
b. / ionic reaction. / d. / double-displacement reaction.

____53.In what kind of reaction does a single compound produce two or more simpler substances?

a. / decomposition reaction / c. / displacement reaction
b. / synthesis reaction / d. / ionic reaction

____54.The reaction 2KClO3(s)  2KCl(s) + 3O2(g) is a(n)

a. / synthesis reaction. / c. / combustion reaction.
b. / decomposition reaction. / d. / ionic reaction.

____55.In what kind of reaction does one element replace a similar element in a compound?

a. / displacement reaction / c. / decomposition reaction
b. / combustion / d. / ionic reaction

____56.The equation A + BX  AX + B is the general equation for a

a. / double-displacement reaction. / c. / displacement reaction.
b. / decomposition reaction. / d. / combustion reaction.

____57.The reaction Cl2(g) + 2KBr(aq)  2KCl(aq) + Br2(l) is a(n)

a. / synthesis reaction. / c. / displacement reaction.
b. / ionic reaction. / d. / combustion reaction.

____58.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

____59.An element in the activity series can replace any element

a. / in the periodic table. / c. / above it on the list.
b. / below it on the list. / d. / in its group.

____60.What can be predicted by using an activity series?

a. / whether a certain chemical reaction will occur
b. / the amount of energy released by a chemical reaction
c. / the electronegativity values of elements
d. / the melting points of elements

____61.If metal X is lower than metal Y in the activity series, then metal X

a. / replaces ions of metal Y in a solution.
b. / is more active than metal Y.
c. / is less active than metal Y.
d. / forms positive ions more readily than does metal Y.

____62.A precipitate forms in a double-displacement reaction when

a. / hydrogen gas reacts with a metal.
b. / positive ions combine with negative ions.
c. / water boils out of the solution.
d. / a gas escapes.

____63.A balanced chemical equation allows one to determine the

a. / mole ratio of any two substances in the reaction.
b. / energy released in the reaction.
c. / electron configuration of all elements in the reaction.
d. / mechanism involved in the reaction.

____64.The coefficients in a chemical equation represent the

a. / masses, in grams, of all reactants and products.
b. / relative numbers of moles of reactants and products.
c. / number of atoms in each compound in a reaction.
d. / number of valence electrons involved in the reaction.

____65.How many mole ratios can be correctly obtained from the chemical equation 2NON2+O2?

a. / 1 / c. / 4
b. / 3 / d. / 6

____66.In the reaction Ca + Cl2 CaCl2, what is the mole ratio of chlorine to calcium chloride?

a. / 2:3 / c. / 1:2
b. / 2:1 / d. / 1:1

____67.In the reaction N2 + 3H2 2NH3, what is the mole ratio of nitrogen to ammonia?

a. / 1:1 / c. / 1:3
b. / 1:2 / d. / 2:3

____68.In the reaction 2H2 + O2 2H2O, what is the mole ratio of oxygen to water?

a. / 1:2 / c. / 8:1
b. / 2:1 / d. / 1:4

____69.What is the mole ratio of oxygen to phosphorus(V) oxide in the reaction P4(s)+5O2(g)P4O10(s)?

a. / 1:1 / c. / 5:1
b. / 1:5 / d. / 4:10

____70.In the chemical equation wA + xB yC + zD, if one knows the mass of A and the molar masses of A, B, C, and D, one can determine

a. / the mass of any of the reactants or products.
b. / the mass of B only.
c. / the total mass of C and D only.
d. / the total mass of A and B only.

____71.If one knows the mass and molar mass of reactant A and the molar mass of product D in a chemical reaction, one can determine the mass of product D produced by using the

a. / mole ratio of D to A from the chemical equation.
b. / group numbers of the elements of A and D in the periodic table.
c. / estimating bond energies involved in the reaction.
d. / electron configurations of the atoms in A and D.

____72.What is needed to calculate the mass of ammonia gas produced from 2.0 L of nitrogen gas in excess hydrogen gas in the reaction below?

N2(g) + 3H2(g)  2NH3(g)

a. / one molar mass and one mole ratio
b. / one molar masses and two mole ratios
c. / two molar masses, one density, and one mole ratio
d. / two densities, two molar masses, and two mole ratios

____73.A chemical reaction involving substances A and B stops when B is completely used. B is the

a. / excess reactant. / c. / primary reactant.
b. / limiting reactant. / d. / primary product.

____74.The substance that restricts the participation of other reactants in a chemical reaction is known as the

a. / limiting reactant. / c. / excess reactant.
b. / limiting product. / d. / excess product.

____75.The substance not completely used up in a chemical reaction is known as the

a. / limiting reactant. / c. / excess reactant.
b. / limiting product. / d. / excess product.

____76.To determine the limiting reactant in a chemical reaction, one must know the

a. / available amount of one of the reactants.
b. / amount of product formed.
c. / available amount of each reactant.
d. / speed of the reaction.

____77.What is the ratio of the actual yield to the theoretical yield, multiplied by 100%?

a. / mole ratio / c. / molar yield
b. / percentage yield / d. / excess yield

____78.What is the measured amount of a product obtained from a chemical reaction?

a. / mole ratio / c. / theoretical yield
b. / percentage yield / d. / actual yield

____79.Actual yield must be determined by

a. / experiments. / c. / theoretical yield.
b. / calculations. / d. / estimation.

____80.The actual yield of a chemical reaction is

a. / less than the theoretical yield. / c. / equal to the percentage yield.
b. / greater than the theoretical yield. / d. / greater than the percentage yield.

____81.For the reaction SO3 + H2O  H2SO4, calculate the percentage yield if 500.g of sulfur trioxide react with excess water to produce 575g of sulfuric acid.

a. / 82.7% / c. / 91.2%
b. / 88.3% / d. / 93.9%

____82.For the reaction Cl2 + 2KBr  2KCl + Br2, calculate the percentage yield if 200.g of chlorine react with excess potassium bromide to produce 410.g of bromine.

a. / 73.4% / c. / 90.9%
b. / 82.1% / d. / 98.9%

____83.For the reaction 2Na + 2H2O  2NaOH + H2, calculate the percentage yield if 80.g of water react with excess sodium to produce 4.14g of hydrogen.

a. / 87% / c. / 92%
b. / 89% / d. / 98%

____84.For the reaction 2Na + Cl2 2NaCl, calculate the percentage yield if 200.g of chlorine react with excess sodium to produce 240.g of sodium chloride.

a. / 61.2% / c. / 83.4%
b. / 72.8% / d. / 88.4%

____85.In the chemical equation wA + xB yC + zD, how many correct mole ratios can be obtained that relate only the products?

a. / 1 / c. / 4
b. / 2 / d. / 6

____86.In the chemical equation wA + xB yC + zD, a comparison of the number of moles of A to the number of moles of C would be a

a. / mass ratio. / c. / electron ratio.
b. / mole ratio. / d. / energy proportion.

____87.In the reaction, CH4(g) + 2O2(g)  CO2(g) + 2H2O(g), a mass of 25gCO2 is produced by reacting methane with excess oxygen. The following expression calculates the

a. / mass of water produced. / c. / minimum mass of oxygen needed.
b. / moles of carbon dioxide produced. / d. / moles of methane consumed.

____88.To determine the limiting reactant in a chemical reaction involving known masses of the two reactants, A and B, which of the following calculations would be the most useful?

a. / determining the masses of 100 mol A and 100 mol B
b. / finding the masses of the products
c. / calculating bond energies
d. / calculating the mass of a single product formed from each reactant

____89.For the reaction CH4(g) + 2O2(g)  CO2(g) + 2H2O(g), calculate the percentage yield of carbon dioxide if 1000. g of methane react with excess oxygen to produce 2300.g of carbon dioxide.

a. / 83.88% / c. / 92.76%
b. / 89.14% / d. / 96.78%

Completion

Complete each sentence or statement.

90.If you have 1.204  1024 atoms of nickel, you have ______as the amount of nickel.

91.The conversion factor used to change moles to number of particles is ______.

92.The average atomic mass of cobalt is ______.

93.Comparing the average atomic masses of copper and zinc, the average atomic mass of ______is larger.

94.The empirical formula for a compound shows the symbols of the elements with subscripts indicating the ______.

95.In one mole of acetic acid, CH3COOH, there are ______moles of hydrogen atoms.

96.Two moles of carbon atoms are present in ______of C6H6.

97.The molar mass of barium nitrate, Ba(NO3)2, is ______.

98.The first step in finding an empirical formula from percentage composition is to assume that you have ______grams of sample.

99.To find an empirical formula from percentage composition, you must divide the number of grams of each element by that element’s ______.

100.A compound’s empirical formula is N2O5. If the formula mass is 108 amu, its molecular formula is ______.

101.A compound’s empirical formula is CH3. If the formula mass is 30 amu, its molecular formula is ______.

102.To calculate the percentage composition of NiCl2, you need to know ______.

103.A solid produced by a chemical reaction that then separates from the solution is called a(n) ______.

104.In writing a formula equation for a reaction that produces hydrogen gas, the correct representation of hydrogen gas is ______.

105.The mass of the products of the reaction C2H5OH + 3O2 2CO2 + 3H2O equals the mass of the reactants because the products are made up of the same ______as the reactants.

106.In an equation, the symbol for a substance in water solution is ______.

107.When the formula equation Fe3O4 + Al  Al2O3 + Fe is correctly balanced, the coefficient of Fe is ______.

108.When the formula equation H2(g) + Cl2(g)  HCl(g) is correctly balanced, the coefficient of HCl is ______.

109.When the formula equation CuSO4(aq) + Fe(s)  Fe2(SO4)3(aq) + Cu(s) is correctly balanced, the coefficient of CuSO4(aq) is ______.

110.The reaction 2HgO(s)  2Hg(l) + O2(g) is classified as a(n) ______reaction.

111.The equation AX  A + X is the general equation for a(n) ______reaction.

112.The reaction Mg(s) + 2HCl(aq)  H2(g) + MgCl2(aq) is classified as a(n) ______reaction.

113.When placed in water, a metal more active than hydrogen will form two substances, a metal hydroxide and ______gas.

114.In a(n) ______reaction, ions of two compounds exchange places in aqueous solution to form new compounds.

115.Ions that are present in solution in which a reaction is taking place but that do not participate in the reaction are called ______.

116.In the chemical equation 2AlCl3(aq) + 3Pb(NO3)2(aq)  3PbCl2(s) + 2Al(NO3)2(aq), the spectator ions are ______and ______.

117.The ratios obtained from the coefficients of substances in a balanced chemical equations are called ______because they can be used to convert moles of one substance to moles of another substance.

118.The unit of the following expression is ______.

119.The unit of the following expression is ______.

120.The expression below converts the quantity, mass HCl, to the quantity, ______.

121.The conversion factor can be used to find the ______of water if you know its mass.

122.The expression below converts the quantity, volume C5H12, to the quantity, ______.

123.The expression below can be used to find the ______of 1016 molecules of CCl4.

124.The substance that controls the quantity of product than can be formed in a chemical reaction is the ______.

125.The substance that is not used up completely in a chemical reaction is the ______.

126.Almost all of the gas inside an inflated automobile safety air bag is molecular ______.

127.The function of the carburetor in a small internal combustion engine is to control the ratio of ______to oxygen.

128.One of the functions of a(n) ______is to increase the rate of the decomposition of NO(g) and NO2(g) found in the exhaust gases of a car into N2(g)andO2(g).

129.The proportions of the reactants and products involved in a chemical reaction are shown by the ______in the balanced chemical equation describing the reaction.

130.In the equation N2 + 3H2 2NH3, the ratio 2:1 relates mol NH3 to mol ______.

131.In the equation N2 + 3H2 2NH3, the mole ratio of N2 to H2 is ______.

132.In the equation N2 + 3H2 2NH3, the mole ratio of NH3 to N2 is ______.

133.The unit of the expression mol H2O  molar mass H2O is ______.

134.The expression below converts the quantity, mass HCl, to the quantity, ______.

135.Unwanted reactions that can use up reactants without making the desired products are called ______reactions

136.If 2 moles of each reactant are available for the reaction described by the following equation,

SiO2(s) + 3C(s)  SiC(s) + 2CO(g),

______is the substance that is the limiting reactant.

137.The efficiency of a reaction is described by the ______yield.

138.In an operating car engine, the least fuel-oxygen ratio should occur when the car’s engine is ______.

139.Reactions that are started by the sun’s ultraviolet light and involve nitrogen oxides emitted from car engines form ______smog.

Problem

140.The mass of 1 mol of gold atoms is 196.97 g. Find the mass of 1 atom of gold.

141.How many moles of copper are present in 180.0gCu?

142.How many moles of oxygen atoms are present in 2.0 grams of oxygen gas, O2?

143.Argentite is a silver ore that contains 87% silver and 13% sulfur. What is the empirical formula for argentite?

144.Calculate the percentage of sulfur in CuSO4.

145.Calculate the percentage of oxygen in Fe2SiO4.

146.Calculate the percentage of aluminum in Al2O3.

147.Write a balanced chemical equation for the following reaction. iron plus copper(I) nitrate yields iron(II) nitrate plus copper.

148.Write a balanced chemical equation for the following reaction. mercury(II) oxide (heated) yields mercury + oxygen

149.Write a balanced chemical equation for the following chemical reaction. methane+oxygencarbondioxide+water