what is the mass of H2 in grams?

Question

In a mixture of Ne and H2 gases, the partial pressure of Ne is 0.150 atm. The total pressure is 0.405 atm. The temperature is 36.0oC. If the total volume of the gas mixture is 433 mL, what is the mass of H2 in grams?

Answer 1

First, the percent of H2 (mole basis) is proportional to its partial pressure, which is 0.255 atm or about 63 per-cent. You can determine total moles from the ideal gas law. Then 63 per-cent of those moles are H2. Multiply by 2 g/mole to get mass.

Answer 2

Total pressure is equal to the sum of the pressure of each gas in the container.

So, .405 atm = .150 atm + pressure of H2.

Now you know that the pressure of H2 is .255 atm.

Now use the law of partial pressure, and molar ratio, which is

Total pressure x calculated mass (g)
-----------------------
partial pressure

which gives you grams of your substance

.405 atm x 2.016 g
-----------
.255 atm

= 3.201 g H2

Answer 3

mH2=?

Tp=0.405 atm and PP Ne=0.150 atm
so, PP H2=0.405-0.150=0.255 atm

T=36C=309K V=0.433 L
PV=nRT remember?
nH2=(PV)/(RT) and nH2=(0.255*0.405)/(0.082*309)mols
nH2=0.00408 mols

Obs: Always use T in Kelvin and confirm the number of constant R (is the that have atm, L and K)

and:
1 mol H2 = 2g
0.00408mols = m

m=?