Partial Pressure Question!!!! HELP!?

Question

A mixture of 2g of CH4 and 1.65g of Si2H6, both gases, are placed in a flask. The total pressure exerted by this mixture is 102kPa. What is the partial pressure?

Any ideas?

Answer 1

Molecular weight CH4 = 14 g/mol
moles CH4 = 2 g / 16 = 0.125

Molecular weight Si2H6 = 62.17 g/mol
moles Si2H6 = 1.65 / 62.17 = 0.0265

Total moles = 0.1515

We can use the equation
Pa / Pt = Na / Nt

Pa = Na / Nt x P t = 0.125 x 102 / 0.1515 = 84.1 kPa is the partial pressure of CH4

Partial pressure Si2H6 = 102 - 84.1 = 17.9 kPa

Answer 2

CH4 has a molecular mass of12+4 =16 so 2g=2/16=0.125mole
Si2H6 has a molecular mass of 28*2+6 =62 and 1.65g correspond to 1.65/62 =0.0266mole
the total number of mole are 0.125+ 0.0266=0.1516mole

molar fraction of CH4 is 0.125/0.1516 =0.825 and the partial pressure of CH4 is 0.825*102=84.1kPa

the partial pressure of Si2H2 = total pressure -pressure CH4
=102-84.1= 17.9 kPa

I gave in this form the solution in order that you see all the methods to calculate partial pressures

Answer 3

CH4 =16g/mol Therefore, 2g=2/16=0.125 mole
Si2H6 = 62g/mol Therefore, 1.65g corresponds to 1.65/62 =0.0266 mole.

Total moles = 0.125+ 0.0266=0.1516mole

Mole Fraction of CH4 = 0.125/0.1516 =0.825

The Partial Pressure of CH4 is 0.825 x 102=84.1kPa

The Partial Pressure of Si2H2 = Total pressure -pressure CH4
=102-84.1= 17.9 kPa = 17900 Pa

Answer 4

Find the molar ratio of the two chemicals. PV=nRT. At fixed V and T, the partial pressure P is dependent only on the number of moles Therefore, the mole ratio is the same as the ratio of partial pressures.

Answer 5

First find the mole of both the substances. The ratio of the moles of the substances indicates the ratio of their respective partial pressure..