A gas has a volume of 750 mL at a pressure of 2.15 atm. What will the pressure be if the volume becomes 1.25 L?

1.29 atm.

Explanation:

To calculate the volume of a gas, we can use the general law of ideal gas: PV = nRT.

where, P is the pressure of the gas in atm.

V is the volume of the gas in L.

n is the no. of moles of the gas in mol.

R is the general gas constant,

T is the temperature of the gas in K.

If n and T are constant, and have two different values of V and P:

P₁V₁ = P₂V₂

P1 = 2.15 atm, V1 = 750 mL = 0.75 L.

P₂ = ? atm, V₂ = 1.25 L.

∴ P₂ = P₁V₁/V₂ = (2.15 atm) (0.75 L) / (1.25 L) = 1.29 atm.