Honors Chemistry-Benchmark #1 (Spring 2012)
Name_________________________
1. [SC2b] Which of the following does NOT describe evidence of a chemical reaction?
A. An iron nail changes to a brownish-orange color.
B. An ice cube melts into liquid water.
C. An antacid tablet produces bubbles of gas when placed in water.
D. A piece of zinc raises the temperature of an acid upon mixing.
2. [SC2c] The molecular formula of a compound is X6Y3. What is the empirical formula for this compound?
A. X6Y
B. XY3
C. X2Y
D. XY2
3. [SC2c] Zinc is used as a coating on iron and steel to prevent corrosion. What is the mass, in grams, of
0.0650 mol Zn?
A. 3.25 g
B. 3.90 g
C. 3.94 g
D. 4.25 g
4. [SC2c] What is the total number of atoms contained in 2.00 moles of helium?
A. 15.999
B. 32.0
C. 6.02 x 1023
D. 1.20 x 1024
5. [SC2c] A compound has the formula MgSO4 • 7 H2O. Its chemical name is ____.
A. aqueous magnesium sulfate
C. magnesium sulfate heptahydrate
B. magnesium sulfate pentahydrate
D. magnesium sulfate decahydrate
6. [SC2c] Indium (In) is a relatively rare earth element that never occurs as a free metal. It is usually found in
a compound that contains 70.48% In and 29.52% S. What is the empirical formula for this compound?
A. InS
B. In2S3
C. In3S5
D. In6S9
7. [SC2c] A student measures 10.0 g of hydrated sodium carbonate (Na2CO3 • x H2O) and places it in a
crucible. After heating, 3.7 g of anhydrous sodium carbonate (Na2CO3) remains. What is the formula for the
hydrate?
A. Na2CO3 • 2H2O
B. Na2CO3 • 5H2O
C. Na2CO3 • 8H2O
D. Na2CO3 • 10H2O
8. [SC2c] Potassium nitrate, also known as saltpeter, is used in matches. What is the percent by mass of
potassium (K) in potassium nitrate (KNO3)?
A. 38.6%
B. 45.9%
C. 55.7%
D. 56.6%
9. [SC2c] Baking soda is the common name for sodium hydrogen carbonate (NaHCO3). What is the mass
in grams of 2.75 moles of sodium hydrogen carbonate?
A. 63.2 g
B. 84 g
C. 210 g
D. 231 g
10. [SC2c] A mole of carbon-12 atoms will have a total mass of _____.
A. 12 kg
B. 12 g
C. 12 amu
D. 6 amu
11. [SC2a] According to the law of conservation of matter, the total mass of the reacting substances is ____.
A. always more than the total mass of the products.
B. always less than the total mass of the products.
C. sometimes more and sometimes less than the total mass of the products.
D. always equal to the total mass of the products.
12. [SC2a] In a chemical reaction, the symbols (aq) indicates that the substance is _____.
A. water
B. dissolved in water
C. a liquid
D. insoluble
13. [SC2d] The ratio of chlorine to hydrogen chloride in the reaction H2(g) + Cl2(g)  2HCl(g) is ____.
A. 1:1
B. 1:2
C. 2:1
D. 2:2
14. [SC2d] The coefficients in a chemical equation _____.
A. show the number of grams of each substance that would react.
B. indicate the number of moles of each substance.
C. are the molar masses of the substances.
D. show the valence electrons for each atom.
15. [SC2a] A reaction in which the ions of two compounds exchange places in aqueous solution to form two
new compounds is called a(n) _____.
A. synthesis reaction
C. double displacement reaction
B. decomposition reaction
D. combustion reaction
16. [SC2a] To balance a chemical equation, it is permissible to adjust the _____.
A. coefficients
B. subscripts
C. formulas of the products
D. number of products
17. [SC2a] In the reaction CH4 + 2O2  CO2 + H2O , oxygen is a _____.
A. subscript
B. coefficient
C. reactant
D. product
18. [SC2a] In order to balance the equation below, the following set of coefficients should be used.
____ C2H2 (g) + ____ O2 (g)  ____ CO2(g) + ____ H2O (l)
A. 1, 1, 2, 1
B. 2, 2, 2, 1
C. 2, 5, 4, 2
D. 2, 4, 4, 2
19. [SC2a] A coefficient of _____ should be placed before H2O in order to balance the following equation
_____Fe(OH)3  ______ Fe2O3 + ______H2O.
A. 3
B. 2
C. 6
D. 1
20. [SC2a] The general form for a single displacement reaction is _____.
A. element + compound  element + compound
B. compound + compound  compound + compound
C. compound  two or more elements or compounds
D. element or compound + element of compound  compound
21. [SC2a] Which of the following equations shown below is balanced correctly?
A. C + O2  2CO
C.
C + O2  CO
B. C + O2  CO2
D.
2C + O  2CO
22. [SC2a] KClO3  2KCl + 3O2 is an example of a ____ reaction.
A. synthesis
B. single displacement
C. decomposition
D. double displacement
23. [SC2d] For the reaction N2 + 3H2  2NH3, _____ mol of N2 is required to produce 18 mol of NH3.
A. 9
B. 27
C. 18
D. 36
24. [SC2e] If a chemical reaction involving substances A and B stops when B is completely used, then B is
referred to as the _____.
A. excess reactant
B. primary reactant
C. limiting reactant
D. primary product
25. [SC2e] The measured amount of a product obtained from a chemical reaction is called the _____.
A. mole ratio
B. theoretical yield
C. percentage yield
D. actual yield
26. [SC2c] You calculate the mole ratio of oxygen to aluminum in a compound to be 1.5 mol O : 1 mol Al.
What is the empirical formula of the compound?
A. Al1O1.5
B. AlO2
C. Al2O3
D. AlO3
27. [SC2e] A jar Is placed over a burning candle. The limiting reactant is the ____.
A. oxygen
B. fire
C. candle
D. jar
28. [SC2b] When zinc reacts with hydrochloric acid, the test tube becomes hot. This is an example of
an _____ reaction.
A. Endothermic
B. exothermic
29. [SC2c] Which of the following is the largest quantity?
A. 2 moles of O2
B. 48 grams of O2
C. 1.505 x 1024 molecules of O2
D. half of Avogadro’s number
30. [SC2c] You know that the experimental molecular mass of a compound is three times the molar mass of
the empirical formula. If the compound’s empirical formula is NO2, what is its molecular formula?
A. NO2
B. NO6
C. N3O2
D. N3O6
Use the following equation to answer questions 30-33.
_____ Cu
+
____AgNO3

____Ag
+
_____Cu(NO3)2
31. [SC2e] If 95.3 g of Cu are reacted with 127.5 g of AgNO3, how many grams of silver can be produced?
A. 81 g
B. 162 g
C. 243 g
D. 324 g
32. [SC2e] Which reactant is the limiting reactant?
A. Cu
B. AgNO3
C. Ag
D. none of the above
33. [SC2e] If 75 g is actually produced, what is the % yield for the reaction?
A. 92.5%
B. 46.3%
C. 30.9%
D. 23.1%