A sealed flask contains 1 mole of hydrogen and 3 moles of helium gas at 20DC. If the total pressure is 40kPa, what is the partial pressure of the Hydrogen gas?

AND :)

The data below was obtained by a student in order to determine the percent of water in a Hydrate:

Mass of the Hydrate..............5.0gram
Mass of the Anhydrous Compound.. 3.2gram

What is the percent in the Hydrate?

PLEASE ANSWER THESE ASAP :D

2 answers

20 kpa
Use Raoult's Law
Pa=XaPt
where Xa is the mole fraction (1/4) and Pt is the total pressure which is 40.
So (1/4)40=10kPa