Exploring Creation Chemistry Module #11 Test
Enter your Name:
Enter your E-mail Address:
01. Define solubility.
02. If a solid solute's solubility decreases when the temperature increases, does the solute dissolve exothermically or endothermically?
03. If a solute's solubility increases with decreasing temperature, is it more likely a solid, liquid, or gas?
04. A chemist is trying to dissolve a solid in water. If the chemist feels the beaker get hot while trying to make the solution, what can the chemist do to increase the solid's solubility?
05. A chemist finds out that a sample of alcohol has been contaminated with a gas. What can the chemist do to get rid of the majority of this dissolved contaminant?
06. What kind of solute (solid, liquid, or gas) usually increases in solubility with increasing temperature?
07. Pick the solute that will raise a liquid's boiling point the most:
NH
3
, Na
3
PO
4
, K
2
CO
3
, NaCl
08. A student makes a solution by measuring out 100 grams of solute and dissolving it in lots of water. The student then measures the mass of the resulting solution. He converts the mass of the solute into moles and divides that by the mass (in kg) of the solution. He reports the result as the molality of the solution. Why is the student wrong?
09. When NaI is added to a solution of Cu(NO
3
)
2
, the following reaction occurs:
2NaI (aq) + Cu(NO
3
)
2
(aq) -> CuI
2
(s) + 2NaNO
3
(aq)
If a chemist needs to make 350.0 g of CuI
2
, how many mL of a 3.3 M solution of NaI must be used? Assume that there is excess copper (II) nitrate.
10. Hydrogen peroxide is used to clean small wounds. It has a limited shelf-life, however, because the following decomposition reaction occurs:
2H
2
O
2
(aq) -> 2H
2
O (l) + O
2
(g)
This is why you often hear a gas release when you open a bottle of old hydrogen peroxide. If 35 mL of a 1.20 M solution of hydrogen peroxide completely decomposes, how many grams of oxygen are produced?
11. What is the molality of a solution made from 5.61 moles of KCl and 2.11 kg of water?
12. If you have 670.0 grams of water and wish to make a 2.13 m solution of KBr, how many grams of the solute would you have to add to the water that you have?
13. When a certain amount of MgF
2
is added to water, the freezing point lowers by 3.5 °C. What was the molality of the magnesium fluoride? (K
f
for water = 1.86
)
14. Benzene (a popular purely covalent solvent) has a freezing point of 5.5
°
C and a K
f
of 5.12
. If 30.0 g of CCl
4
are dissolved in 350.0 g of benzene, what will the freezing point of the solution be?
15. Acetic acid has a boiling point of 118.5
°
C and a K
b
of 3.08
. What is the boiling point of a 3.20 m solution of Ca(NO
3
)
2
in acetic acid?