Question

A 12​-liter ​[l] flask contains 1.3 moles​ [mol] of an ideal gas at a temperature of 20 degrees celsius ​[degrees​c]. What is the pressure in the flask in units of atmospheres​ [atm]

Answer 1

Given: Volume of flask=12 L

Number of moles of an ideal gas=1.3 mol

Temperature=20°C

Gas is an ideal gas thus, it follows the ideal gas equation as follows:

`PV=nRT`

Here, P is pressure, V is volume, n is number of moles, R is Universal gas constant
`0.0821 atm L K^(-1) mol^(-1)` and T is temperature.

First convert temperature from °C to K as follows:

`0 ^(o)C=273.15 K`

Thus,

`20 ^(o)C=293.15 K`

Rearrange ideal gas equation to calculate pressure,

`P=(nRT)/(V)`

Putting the values,

`P=((1.3 mol)(0.0821 atm L K^(-1)mol^(-1))(293.15 K))/((12 L))=2.6 atm`

Therefore, pressure in the flask will be 2.6 atm.