A30.0 ml sample of hydrogen gas (h2) is collected over water at 20.00∘c and has a total pressure of 700.0 torr. the partial pressure of water vapor at 20.00∘c is 17.5 torr. calculate the mole fraction of h2 gas in the sample.

The mole fraction of hydrogen gas at 20°C is 0.975  

Explanation:

We are given:

Vapor pressure of water vapor at 20°C = 17.5 torr

Total pressure at 20°C = 700.0 torr

Vapor pressure of hydrogen gas at 20°C = (700.0 - 17.5) torr = 682.5 torr

To calculate the mole fraction of hydrogen gas at 20°C, we use the equation given by Raoult's law, which is:

where,

= partial pressure of hydrogen gas = 682.5 torr

= total pressure = 700.0 torr

= mole fraction of hydrogen gas = ?

Putting values in above equation, we get:

Hence, the mole fraction of hydrogen gas at 20°C is 0.975

a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o