Question

how many moles of gas does it take to occupy 120 liters at a pressure of 2.3 atmospheres and a temperature of 340 K?

Answer 1

Data:

P (pressure) = 2.3 atm
V (volume) = 120 L
T (temperature) = 340 K
n (number of mols) = ?
R (Gas constant) = 0.082 (atm*L/mol*K)

Formula: 

$p*V = n*R*T$

Solving:
$p*V = n*R*T$
$2.3*120 = n*0.082*340$
$276 = 27.88n$
$27.88n = 276$
$n = \frac{276}{27.88}$
$n = 9.89956...\to \boxed{\boxed{n\approx 9.90\:mols}}\end{array}}\qquad\quad\checkmark$