# PRACTICE PROBLEMS

## Solution Concentrations and Conversions

1. What is the molarity of a solution that is prepared by dissolving
0.178 moles of NaCl in enough water to make 455 mL of solution?
a) 0.178 M | b) 0.255 M | c) 0.391 M |
d) 0.301 M | e) 0.775 M |

2. What is the molarity of a solution prepared by dissolving 25.7 g
NaCl in enough water to make 153 mL of solution?
a) 0.0257 M | b) 0.257 M | c) 0.963 M |
d) 1.475 M | e) 2.87 M |

3. What is the molality of a solution prepared by dissolving 0.785
moles of KI in 895 g of water?
a) 0.102 m | b) 0.877 m | c) 1.304 m |
d) 2.709 m | e) 3.887 m |

4. What is the molality of a solution prepared by dissolving 25.4 g KI
in 963 g of water?
a) 0.159 m | b) 0.372 m | c) 0.651 m |
d) 0.798 m | e) 1.016 m |

5. What is the molality of a 1.75 M solution of Na_{2}CO_{3}
in water? The density of this solution is 1.112 g/mL.
a) 0.995 m | b) 1.15 m | c) 1.75 m |
d) 1.89 m | e) 2.87 m |

6. What is the molarity of a 2.55 m solution of KI in water? The density of
this solution is 1.254 g/mL.
a) 1.17 M | b) 2.25 M | c) 3.81 M |
d) 4.22 M | e) 5.21 M |

7. What is the mole fraction of NaCl in a solution prepared by dissolving
1.54 moles of NaCl in 9.73 moles of water?
a) 0.154 | b) 0.732 | c) 0.137 |
d) 0.896 | e) 0.443 |

8. What is the mole fraction of NaCl in a solution prepared by dissolving
15.11 g NaCl in 275.2 g H_{2}O?
a) 0.055 | b) 0.939 | c) 0.601 |
d) 0.017 | e) 0.151 |

9. What is the mole fraction of KI in a solution that is 0.273 m KI?
a) 0.005 | b) 0.273 | c) 0.178 |
d) 0.593 | e) 0.872 |

10. What is the molality of NaCl in an aqueous solution in which the mole
fraction of NaCl is 4.24 x 10^{-2}?
a) 1.17 m | b) 2.46 m | c) 4.07 m |
d) 5.19 m | e) 5.93 m |

11. What is the mass percentage of sucrose, C_{12}H_{22}O_{11} in a solution prepared by dissolving 5.17 g of sucrose
in 89.74 g of water?
a) 11.15% | b) 8.99% | c) 7.18% |
d) 5.76% | e) 5.45% |

12. What is the molality of a 15.21% C_{12}H_{22}O_{11} solution?
a) 0.253 m | b) 0.524 m | c) 0.769 m |
d) 0.872 m | e) 1.908 m |

13. What is the percent by mass of KCl in a 1.53 m KCl solution?
a) 8.15% | b) 6.17% | c) 5.98% |
d) 10.2% | e) 19.3% |

14. What is the mole fraction of NaI in a solution that is 17.85% NaI
by mass?
a) 1.17 x 10^{-3} |
b) 2.55 x 10^{-2} |
c) 4.18 x 10^{-2} |

d) 8.85 x 10^{-2} |
e) 1.92 x 10^{-1} |

15. What is the percent by mass of HCl in a solution in which the mole
fraction of HCl is 1.48 x 10^{-2}?
a) 15.45% | b) 10.22% | c) 8.19% |
d) 4.16% | e) 2.95% |

16. What is the molarity of NaCl in a solution that is 5.02% NaCl by mass?
The density of this solution is 1.028 g/mL.
a) 0.113 M | b) 0.415 M | c) 0.883 M |
d) 1.172 M | e) 1.398 M |

17. What is the percent by mass of CaCl_{2} in a 2.78 M
CaCl_{2} solution? The density of the solution is 1.165
g/mL.
a) 26.5% | b) 35.8% | c) 47.2% |
d) 59.6% | e) 64.7% |

18. What is the mole fraction of HCl in a 3.48 M HCl solution? The
density of the solution is 1.058 g/mL.
a) 1.08 x 10^{-3} |
b) 2.24 x 10^{-3} |
c) 1.21 x 10^{-2} |

d) 6.31 x 10^{-2} |
e) 1.15 x 10^{-1} |

19. What is the molarity of a NaCl solution in which the mole fraction
of NaCl is 9.11 x 10^{-3}? The density of the solution
is 1.016 g/mL.
a) 0.217 M | b) 0.503 M | c) 0.894 M |
d) 1.173 M | e) 1.767 M |

20. How many milliliters of a 0.20 M NaOH solution would be required in
order to have 5.15 g NaOH?
a) 203 mL | b) 321 mL | c) 493 mL |
d) 558 mL | e) 644 mL |

QUICK ANSWERS

1 c 2 e 3 b 4 a
5 d 6 b 7 c 8 d
9 a 10 b

11 e 12 b 13 d 14 b
15 e 16 c 17 a 18 d
19 b 20 e

*This page was last modified Wednesday February 10, 1999*