For 32, use Henry's law. It says C=kP_gas where C is the solubility of the gas at some temperature, k is Henry's law constant, and P_gas is the partial pressure of the gas. Thus k=C/(P_gas). From the information we can calculate the solubility in the second scenario, and thus can find the pressure because we know solubility and pressure for one situation.
For 33, it is what it sounds like. We find the percent of mass that is the solute. This is (8.55/(8.55+78.00))*100%
34 is merely dimensional analysis. .250L*(3.75mole/L)*(74g/mole)= .250*3.75*74 grams.