how many moles of CO2 and g of CO2

Question

How many moles of CO₂ that exert a pressure of 1.03 atm at a volume of 32.5 L and a temperature of 32.0 ^oC? What is the mass of the CO₂? (R = 0.0821)

Answer 1

Hello, Kadie,

We use the ideal gas law to find the moles of CO₂ under the specified conditions.

PV = nRT where n is the moles and R the gas constant, which was provided in the problem.

Rearrange to solve for the unknown, n:

n = PV/RT

Enter the data. The gas constant that is provided has units of L*atm*K⁻¹⋅mol⁻¹, and the data are consistent with these units, with the exception of temperatrure. We are given C, but we need Kelvin, as do most of the gas laws. Add 273.15 to 32C to obtain degrees K.

n = (1.03)(32.5L)/(0.821 L*atm*K⁻¹⋅mol⁻¹)(305.2K)

I get 1.34 moles CO₂. At a molar mass of 44.0 g/mole, that is 58.8 grams of CO₂.

Bob