Question

Be sure to answer all parts.

An environmental chemist sampling industrial exhaust gases from a coal-burning plant collects a CO₂−SO₂−H₂O mixture in a 21.0−L steel tank until the pressure reaches

893.9 torr

at

43.0

°

C.

(a) How many moles of gas are collected?

mol gas

(b) If the SO₂ concentration in the mixture is 9.81

×

10³ parts per million by volume (ppmv), what is its partial pressure?
[Hint: ppmv = (volume of component/volume of mixture)

×

10⁶.]

torr

Answer 1

To solve this question, we will use the ideal gas equation:

With an R value of:

To calculate, we must apply conversion unit factors, as follows:

(a) How many moles are collected?

(b) Partial pressure of SO₂:

According to the Dalton's Law, every gas in the mixture has a partial pressure given by equation:

Where P_i is the partial pressure of component i

Y_i is the mole fraction of component i in the mixture

P_T is the total pressure.

We have a SO₂ concentration of:

For ideal gases in a closed reservoir, we can apply:

It is to say, the mole fraction. Hence, we can write the SO2 concentration as:

Solving for Y_i:

And the partial pressure is: