Test ONE Review Probs: (answers follow)
1. In the reaction N2(g) + 3H2(g) –> 2NH3(g), how many moles of ammonia would be produced from 1.0 mol of hydrogen and excess nitrogen?
A. 0.33 mol
B. 3.0 mol
C. 2.0 mol
D. 0.67 mol
E. 1.3 mol
Refer to the following unbalanced equation:
C<sub>6</sub>H<sub>14</sub> + O<sub>2</sub> –> CO<sub>2</sub> + H<sub>2</sub>O
2. What mass of oxygen (O2) is required to react completely with 25.0 g of C6H14?
A. 9.28 g
B. 88.2 g
C. 608 g
D. 32.0 g
E. 16.0 g
3. Calculate the mass of carbon dioxide produced from 11.2 g of octane, C8H18, in the following reaction.
2C8H18(g) + 25O2(g) –> 16CO2(g) + 18H2O(g)
A. 58.9 g CO2
B. 17.3 g CO2
C. 34.5 g CO2
D. 89.6 g CO2
E. 46.2 g CO2
4. Fe2O3 (molar mass = 159.7 g/mol) reacts with CO (molar mass = 28.0 g/mol) according to the equation
Fe2O3(s) + 3CO(g) –> 3CO2(g) + 2Fe(s)
When 352 g Fe2O3 reacts with excess CO, what number of moles of Fe (iron) is produced?
5. 18.7 kg of Zn represents how many atoms?
6. Calculate the mass, in grams, of 1.25 x 1026 formula units of sulfur dioxide.
7. 6.00 g of water contains how many molecules of water?
A. 0.333
B. 3.00
C. 2.10 x 1023
D. 3.61 x 1024
E. 4.20 x 1023
8. What is the empirical formula of an oxide of bromine which contains 71.4% bromine?
A. Br2O
B. BrO
C. BrO3
D. BrO2
E. None of the above
9. A hydrocarbon has the formula C2H4. What is the percent by mass of carbon in the compound?
A. 50.0%
B. 85.6%
C. 62.4%
D. 33.3%
E. 92.1%
10. A compound contains 25.94% N and 74.06% O (by mass). What is the empirical formula?
11. Acetylene gas is 92.3% carbon and 7.7% hydrogen (by mass), and its molar mass is 26 g/mol. What is its molecular formula?
A. C2H2
B. CH4
C. CH
D. C4H4
E. None of the above
12. A compound has a molar mass of 100 g/mol and the percent composition (by mass) of 65.45% C, 5.45% H, and 29.09% O. Determine the empirical formula and the molecular formula.
A. CH4O and C3H12O3
B. C3HO and C6H2O2
C. CH2O and C4H8O4
D. C3H3O and C6H6O2
E. CHO and C6H6O6
Answer Sheet
1. D. 0.67 mol
2. B. 88.2 g
3. C. 34.5 g CO2
4. 4.41 mol Fe
5. 1.72 x 1026 atoms
6. 1.33 x 104 g SO2
7. C. 2.10 x 1023
8. D. BrO2
9. B. 85.6%
10. N2O5
11. A. C2H2
12. D. C3H3O and C6H6O2
