Download Pre-AP Chemistry Name: ___Answer Key_____ Review Test 8

Pre-AP Chemistry
Review Test 8:
Name: ___Answer Key_____
Date:__________________
Period: ____
Questions
1. Define the following terms.
a. Reactant(s) are present at the beginning of a chemical reaction and are on the left side of a chemical equation.
b. Product(s) are present at the end of a chemical reaction and are on the right side of a chemical equation.
c. Coefficient(s) are numbers placed in front of chemical formulas when balancing chemical equations.
d. Formula unit. Ionic compounds are called formula units.
e. Limiting reactant is the reactant that makes the least amount of product and runs out first.
f. Excess reactant makes the greater amount of product and is left over at the end of the chemical reaction.
g. Theoretical yield is the amount of product formed when all limiting reactant is used up.
h. Percent yield is calculated by dividing actual yield by actual yield then multiplying by 100.
i. Actual yield is the amount of product actually formed by the chemical reaction.
1. Calculate percent composition for the following compounds.
a. Fe(NO3)3
b. (NH4)2CrO4
molar mass = 241.88 g
molar mass = 152.12 g
2. Perform the following conversions.
a. How many moles are in 22 grams of argon?
0.55 mole Ar
b. How many grams are in 88.1 moles of magnesium? 2.14 x 103 g Mg
c. How moles of AgNO3 are in 8.53 x 1023 F.U. AgNO3?
1.42 mole AgNO3
b. What is the mass of 1.40 x 1025 atoms of Be?
210. grams Be
b. What mass of C6H12O6 contains 7.95 x 1023 carbon atoms?
39.7 grams C6H12O6
b. How many hydrogen atoms are contained in 5.02 moles of C 7H13O?
3.93 x 1025 H atoms
c. What mass of phosphorus is contained in 6.29 x 10 22 molecules of P4O10?
12.9 grams P
e. A weighing boat contains 14.82 g sucrose (C12H22O11). How many moles of sucrose are in the sample? How many
carbon atoms are in this sample?
0.04329 mole C12H22O11
3.127 x 1023 C atoms
f. How many grams of gold(III) nitrate, Au(NO3)3, would contain 9.0 x 1027 atoms of gold? 5.7 x 106 grams Au(NO3)3
7. Find the empirical formula of a compound, given that the compound is found to be 47.9 % zinc and 52.1 % chlorine by mass.
ZnCl2
8.. Ninhydrin’s composition is 60.68 % carbon, 3.40% hydrogen and 35.92 % oxygen. What is the empirical formula?
Empirical formula = C9H6O4
10. The compound benzamide has the following percent composition and a molecular mass of 242 amu. What are the empirical and
molecular formulas?
C = 69.40 % H= 5.825 % O = 13.21 % N= 11.57 %
Empirical formula = C7H7ON
Molecular formula = C14H14O2N2
11. Antibiotics are complex organic chemicals which have the ability to destroy or inhibit the growth of microorganisms such as
bacteria and viruses. Aureomycin is an antibiotic which contains 55.2% C, 26.7% O, 5.85% N, 7.40% Cl and 4.84% H. What is the
empirical and molecular formula of aureomycin which has a molecular mass of 479?
Empirical formula = C22H23O8N2Cl
Molecular formula = C22H23O8N2Cl
12. A component of protein called serine has an approximate molar mass of 315 g/mole. If the percent composition is as follows, what
is the empirical and molecular formula of serine?
C = 34.95 % H= 6.844 % O = 46.56 % N= 13.59 %
Empirical formula = C3H7O3N
Molecular formula = C9H21O9N3
13. How many grams of calcium hydroxide will be formed in the above reaction when 4.44 g of calcium oxide and 7.77 g of water are
available to react? Also identify the limiting and excess reactants.
_____ CaO(s) + _____ H2O(l)  _____ Ca(OH)2(aq)
Amount formed = 5.87 g Ca(OH)2
14. How many grams of hydrogen gas will be produced from the reaction of 3.00 g of magnesium with 4.00 g of hydrochloric acid?
If the reaction yields 0.0943 g H2, what is the theoretical and percent yield? Identify the limiting and excess reactants.
____Mg(s) + _____HCl(aq)
Theoretical yield = 0.111 g H2
Percent Yield = 85.0%

_____MgCl2(aq)
+
_____H2(g)
15. If 6.3 g of sulfur reacts with 10.0 g of oxygen, what is the limiting reactant? If 3.5* grams SO3 are produced, what is the
theoretical and percent yields? *actual yield has been changed*
____S8(s) _____O2(g)  ____ SO3(g)
Theoretical yield = 5.2 g SO3
Percent yield = 67% SO3
16. Give the balanced molecular, total ionic and net ionic equations for the following. All states of matter must be shown in the
molecular equation.
a.
b.
c.
Ca
+
Na2CO3
Mn
+
+
HNO3
Mg(NO3)2
Ni(NO3)2
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