For each problem, you may choose answer "e" if no correct answer is found.
 
 

Indicate the missing words in the following statement: "For an ordinary chemical reaction the mass of the products is __________ the mass of the reactants." a. always less than b. usually more than c. always equal to d. usually less than	Which of the following elemental gases is not represented by a diatomic molecule in a chemical equation? a. hydrogen b. fluorine c. argon d. nitrogen
Which of the following equations is not balanced? a. 2H2 + O2 = 2H2O b. KClO3 = KCl + 2 O2 c. 2SO2 + O2 = 2SO3 d. N2 + 3H2 = 2NH3	Indicate which set of coefficients balances the equation _____CH4 = _____C3H8 + _____H2 a. 3, 1, 1 b. 3, 2, 1 c. 3, 1, 2 d. 6, 2, 2
Indicate which set of coefficients balances the equation _____C4H10 + _____O2 = _____CO2 + _____H2O a. 1, 6, 4, 5 b. 1, 7, 4, 5 c. 1, 3, 4, 5  d. 2, 13, 8, 10	When the equation S8 + O2 + H2O = H2SO4 is correctly balanced, the coefficient front of H2O is a. 4 b. 6 c. 8 d. 12
Which of the following reactions is a combustion reaction? a. Al(OH)3 + 3HCl = AlCl3 + 3H2O b. 2NaHCO3 = Na2CO3 + CO2 + H2O c. 3CuSO4 + Al = Al2(SO4)3 + 3Cu d. C3H8 + 5 O2 = 3CO2 + 4H2O	Which of the following reactions is correctly classified? a. 2NO2 + H2O2 = 2HNO3 (decomposition) b. Fe + CuSO4 = Cu + FeSO4 (synthesis) c. F2 + 2NaCl = Cl2 + 2NaF (single-replacement) d. H2 + Cl2 = 2HCl (double-replacement)
How many moles of NH3 are needed to react exactly with 2.00 moles of O2 according to the following equation:  4NH3 + 3 O2 = 2N2 + 6H2O a. 1.50 moles b. 2.67 moles c. 3.00 moles d. 6.00 moles	In the following reaction, how many grams of H2O are produced if 2.00 g of N2H4 react? N2H4 + 3 O2 = 2NO2 + 2H2O a. 0.562 g b. 1.12 g c. 2.00 g d. 2.25 g
In the reaction  Al2(CO3)3 + 6 HCl ---> 2 AlCl3 + 3 H2O + 3 CO2 how many molecules of CO2 are produced when 2.73 moles of HCl react? a. 2.06 x 1023 b. 4.11 x 1023 c. 8.22 x 1023 d. 1.64 x 1024	If a mixture containing 3.0 moles of N2 and 8.7 moles of H2 is allowed to react according to the equation  N2 + 3H2 = 2NH3 a. 11.7 moles of NH3 can be produced b. N2 is the limiting reactant c. H2 is the limiting reactant d. only 2 moles of NH3 can be produced
If a mixture containing 3.0 moles of A, an unlimited amount of B and 6.0 moles of C is allowed to react according to the equation  2A + 2B + 4C = 4D + 3E a. A will be the limiting reactant b. B will be the limiting reactant c. C will be the limiting reactant d. 2 of the 3 reactants may be considered limiting	How many moles of CO2 can be produced from 28.0 g of CO and 15.0 g of O2 according to the equation  2CO + O2 = 2CO2 a. 0.469 moles b. 0.938 moles c. 1.00 moles d. 1.23 moles
42.6 g of Cu are combined with 84.0 g of HNO3 (formula mass = 63.0), according to the reaction  3Cu + 8HNO3 = 3Cu(NO3)2 + 2NO + 4H2  Which reactant is limiting and how many grams of Cu(NO3)2 (formula mass = 188) are produced? a. Cu, 94.0 g b. Cu, 126 g c. HNO3, 94.0 g d. HNO3, 126 g	92.0 g of Na are combined with 76.0 g of H2O according to the reaction  2Na + 2H2O = 2NaOH + H2  Which reactant is the limiting reactant and how much of the other reactant remains? a. Na, 4.0 g b. H2O, 43.5 g c. Na, 10.0 g d. H2O, 72.0 g
In a certain experiment 5.26 g of Fe(OH)3 (formula mass = 107) was produced from 12.5 g of Fe(NO3)3 (formula mass = 242) reacting with an excess of NH3 and H2O according to the equation  Fe(NO3)3 + 3NH3 + 3H2O =        Fe(OH)3 + 3NH4NO3  What is, respectively, the theoretical yield and percent yield of Fe(OH)3? a. 5.53 g and 42.1% b. 5.53 g and 95.1% c. 16.6 g and 31.7% d. 16.6 g and 42.1%	In a certain experiment using Zn and an excess of S, 30.7 g of ZnS is obtained.  This represents a 93.7 percent yield. What is the theoretical yield of ZnS for this experiment? a. 28.8 g b. 31.2 g c. 32.8 g d. 35.1 g
The following two-step process can be used to produce SO2: 2KClO3 = 2KCl + 3 O2 S8 + 8 O2 = 8SO2 How many moles of SO2 can be produced from 4.00 moles of KClO3? a. 4.00 moles b. 6.00 moles c. 8.00 moles  d. 16.00 moles	In a valid chemical equation a. the number of products must equal the number of reactants b. the reactants always appear on the right-hand side of the equation c. only reactants and products that are solids or liquids are listed d. the total number of atoms on each side of the equation must be equal