If I have an unknown quantity of gas at a pressure of 750 torr, a volume of 25 liters, and a temperature of 300 K, how many moles of gas do I have?

1 mole

Explanation:

Data obtained from the question include:

P (pressure) = 750 torr

But 760torr = 1atm

750 torr = 750/760 = 0.99atm

V (volume) = 25L

T (temperature) = 300K

R (gas constant) = 0.082atm. L/Kmol

n (number of mole) = ?

Using the ideal gas equation PV = nRT, we can easily find the number of mole as illustrated below:

PV = nRT

n = PV / RT

n = 0.99 x 25 / 0.082 x 300k

n = 1 mole

Therefore, the number of mole of the gas is 1 mole