# SAT II Chemistry : Solutions and States of Matter

## Example Questions

### Example Question #1 : Gas Laws

Suppose that an ideal gas at  and 2.0 atm has a volume of 11.2 cubic meters. Which of the following expressions represents the volume of the gas, in cubic meters, if the temperature were increased by  and the pressure decreased to 1.5 atm?

Explanation:

First of all, the unit degrees Celsius should be converted to Kelvins by adding 273. This means that the temperature increases from 273 K to 323 K.

Next, the combined gas law can be used.

Plugging in the known values gives

and solving for the volume gives

Rearranging shows this is clearly equivalent to the correct answer, .

### Example Question #1 : Solutions And States Of Matter

How much faster is the rate of effusion of  than the rate of effusion of ?

Explanation:

By Graham's Law, . The molar mass of  is 2 g/mol and the molar mass of  is 18 g/mol. Thus,

### Example Question #2 : Solutions And States Of Matter

30 mL of 1.0 M    solution is diluted with water to a volume of 3 L. What is the new concentration of the solution?