Question

The mass of 2.43 liters of methane at 2atm and 27°c is?

Answer 1

Explanation:

We have the ideal gas law:

PV = nRT

And P*m = D RT

Where d = density
n = number of moles of gas= 18
w = mass of gas
P = pressure of the gas = 2 atm
T = temperature of the gas =
27° c =273+27=300k

Now 

D =
$\frac{P*m }{RT}$
$D = \frac{2atm \times 16 \frac{g}{mol} }{0.0821 \frac{Latm}{molK} \times 300K \: } \\ = 1.299 \frac{g}{L} \:$

Therefore, the density of methane will be, 1.299 g/L

now you have density and volume
so use the formula
$density = \frac{mass}{volume}$
so
$mass = density \times volume \\ = 1.299 g/L \times 2.43L \: = \\ 3.15657 \:$
so at last mass is 3.15657