Asample contains 18.0 g n2 (mw = 28.02 g/mol), 50.5 g he (mw = 4.00 g/mol), and 34.6 g co2 (mw = 44.01 g/mol). calculate the mole fraction of carbon dioxide in the sample.

The mole fraction of carbon dioxide is 0.0559

In this case, we are given a mixture of N₂, CO₂ and  He

To find the mole fraction of CO₂, first we need to calculate the total number of moles in the mixture.

Individual number of moles for each gas are;

Moles = mass ÷ Molar mass

Therefore;

Nitrogen gas (N₂)

Mass =18.0 g

Molar mass = 28.02 g/mol

                 = 0.642 moles N₂

Helium gas (He)

Mass = 50.5 g

Molar mass = 4.0 g/mol

                = 12.625 moles He

Carbon dioxide (CO₂)

Mass = 34.6 g

Molar mass = 44.01 g/mol

                = 0.786 moles CO₂

Therefore;

The total number of moles in the mixture;

= 0.642 moles + 12.625 moles + 0.786 moles

= 14.053 moles

Thus;

The mole fraction of CO₂= Moles of CO₂ ÷ Total number of moles

                                      = 0.786 moles ÷ 14.053 moles

                                      = 0.0559

Hence the mole fraction of carbon dioxide is 0.0559

o conteúdo de calor de um sistema é igual à entalpia apenas para um sistema que é constante