Average Molecular Weight Calculations

The video tutorial explains how to calculate the average molecular weight of a mixture with two or more components. It covers two methods: using mole fractions and mass fractions. Examples are provided to illustrate the calculations, including the impact of component percentages on the average molecular weight. The tutorial concludes with a practical application in a material balance problem, demonstrating how to convert molar flow rate to mass flow rate using the average molecular weight.

Why is calculating the average molecular weight important in mixtures?

• It determines the electrical conductivity of the mixture.

• It is necessary for calculating the boiling point.

• It is used to convert molar flow rate to mass flow rate.

• It helps in determining the color of the mixture.

Which method is easier when converting molar flow rate to mass flow rate?

• Using mole fractions

• Using density fractions

• Using mass fractions

• Using volume fractions

How do you calculate average molecular weight using mole fractions?

• Multiply mass fractions by molecular weights and sum them.

• Divide mole fractions by molecular weights and sum them.

• Divide mass fractions by molecular weights and sum them.

• Multiply mole fractions by molecular weights and sum them.

In the example with 30% oxygen and 70% hydrogen, what is the average molecular weight using mole fractions?

• 11 grams per mole

• 2.8 grams per mole

• 32 grams per mole

• 2 grams per mole

What is the significance of ensuring the average molecular weight is between the two molecular weights in a mixture?

• It ensures the mixture is homogeneous.

• It confirms the calculation is correct.

• It verifies the components are reactive.

• It guarantees the mixture is stable.

Why is there a significant difference in average molecular weight when using mass fractions?

• Because oxygen has a higher molecular weight than hydrogen.

• Because hydrogen has a much lower molecular weight than oxygen.

• Because the calculation method is incorrect.

• Because the components are not mixed properly.

What happens to the average molecular weight when the proportion of the higher molecular weight component increases?

• It decreases.

• It remains the same.

• It becomes zero.

• It increases.

What is the average molecular weight calculated using mass fractions for 30% oxygen and 70% hydrogen?

• 11 grams per mole

• 2.8 grams per mole

• 32 grams per mole

• 5.8 grams per mole

In the practical problem, what is the molar flow rate of the mixture?

• 32 moles per hour

• 14 moles per hour

• 46 moles per hour

• 500 moles per hour

How many moles of oxygen are present in the mixture with a molar flow rate of 46 moles per hour?

• 70 moles

• 32 moles

• 14 moles

• 46 moles