# Question #e66a1

Jun 14, 2015

Under those conditions for temperature and pressure, 0.3 moles of methane would occupy that volume.

#### Explanation:

You have all the information you need to solve for the number of moles of methane that would occupy 4.3 L at a temperature of 400 K and a pressure of 2 atm.

Your tool of choice will be the ideal gas law equation

$P V = n R T$, where

$P$ - pressure;
$V$ - the volume the gas occupies;
$n$ - the number of moles of gas;
$R$ - the ideal gas constant, equal to $0.082 \left(\text{atm" * "L")/("mol" * "L}\right)$
$T$ - the temperature of the gas.

Plug your values into the equation and solve for $n$

$P V = n R T \implies n = \frac{P V}{R T}$

$n = \left(2 \cancel{\text{atm") * 4.3cancel("L"))/(0.082(cancel("atm") * cancel("L"))/("mol" * cancel("K")) * 400cancel("K}}\right)$

$n = \text{0.262 moles}$

Rounded to one sig fig, the number of sig figs you gave for the temperature of the gas, the answer will be

$n = \textcolor{g r e e n}{\text{0.3 moles}}$