Question

What is the pressure, in torr, of a gas whose density is 8.0 g/L at a temperature of 25 C above standard temperature and whose molecular weight is 75 g/mol?

Answer 1

Use the gas law and solve for the pressure:

PV=nRT

Where

n=moles of gas
L=volume
R=62.3637 L·Torr/mol·K
and
T=273.15K + 25 C=298.15K

The density of the gas is 8.0g/L and the molecular weight of the gas is 75 g/mol

8.0g//75g/mol= x mol/L

Rearrangement of the gas law gives the following:

P=(n/V)*RT


Plug in x mol/L into the equation and plug and chug.

Answer 2

**Fixed a typo that probably would cause confusion.

Use the gas law and solve for the pressure:

PV=nRT

Where

n=moles of gas
L=volume
R=62.3637 L·Torr/mol·K
and
T=273.15K + 25 C=298.15K

The density of the gas is 8.0g/L and the molecular weight of the gas is 75 g/mol

8.0g/L**/75g/mol= x mol/L

***This leaves mol/L

Rearrangement of the gas law gives the following:

P=(n/V)*RT


Plug in x mol/L into the equation and plug and chug.