# A 10 L flask contains 2g of CH4,3g of hydrogen and 4g of nitrogen at 20 ˚ C. a. What is the pressure, in atm inside the flask? b. What is the partial pressure of each component of the mixture of gases?

##### 1 Answer

a)

b) Methane:

I profusely apologize for the long answer, but I knew no shorter way. I assure you, half of it is empty spaces and calculations to make it easier.

#### Explanation:

**a)**

We have

Use the Ideal Gas Law (

**Known values:**

We have to find

**Molar Mass:**

- Methane -
#16.043g# - Hydrogen -
#2.016g# - Nitrogen -
#28.014g#

Now using the formula for moles (

The moles of **methane**:

The moles of **hydrogen**:

The moles of **nitrogen**:

Add them up to find the total moles of gas:

So we have

The formula for pressure using the ideal gas law is:

**So the pressure is (to three significant figures) #4.222atm#.**

**b)**

We have to input the different amounts of moles into the formula. Quite simply, the partial pressure of a particular gas is the pressure if that gas alone occupied the flask.

In this question, we can use our earlier formula:

We can confirm this answer using the formula

**Methane:**

There are

The methane exerts a pressure of

**Hydrogen:**

There are

The hydrogen exerts a pressure of

**Nitrogen:**

There are

The nitrogen exerts a pressure of

To confirm, add up the individual pressures:

You may be confused. Why