Answer:
2.05 moles
Step-by-step explanation:
Considering it as an ideal gas, we must use the ideal gas law:
PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant (0.082 atm*L/mol*K), and T is the temperature.
If the gauge reads zero when 14.7 psi of gas remains, it means that the pressure must be equal to atmospheric pressure, so 1 atm = 14.7 psi.
P = 488 psi * 1atm/14.7psi = 33.20 atm
T = 23ºC + 273 = 296 K
33.20*1.50 = n*0.082*296
24.272n = 49.8
n = 2.05 moles