A sample of carbon dioxide is contained in a 250.0 mL flask at 0.930 atm and 15.4 °C. How many molecules of gas are in the sample?
molecules

We are given:

Volume (V) = 0.25 L

Pressure (P) = 0.93 atm

Temperature (T) = 15.4°C  OR   288.4 K

Solving for the number of moles of CO₂:

From the ideal gas equation:

PV = nRT

replacing the variables

0.93 * 0.25 = n (0.082)(288.4)

n = 0.00983 moles

Number of molecules:

Number of moles=  0.00983

number of molecules in 1 mole = 6.022 * 10²³

Number of molecules in 0.00983 moles = 0.00983 * 6.022 * 10²³

Number of molecules = 5.91 * 10²¹