In this situation, we can use the ideal gas equation which is PV = nRT
P = Pressure (atm)
V = Volume (L)
n = moles (mol)
R = constant (0.08206 atm-l/mol-K)
T = Temperature (K) ---> C + 273.15 = K
PV = nRT
n = PV/RT
= (7atm)(15L) / (0.08206 atm-l/mol-K)(23 + 273.15)
= 4.32 mol
Hope that helped!!!
