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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: MilkyCar on October 24, 2023, 12:44:58 PM

Title: Mole Fractions of Reactants and Products
Post by: MilkyCar on October 24, 2023, 12:44:58 PM
Stuck on this assignment question:

For the following reactions, predict whether the mole fraction of the reactants or products increases or remains the same when the volume of the reaction vessel is increased

a. SO2(g) + 1/2O2(g) ::equil:: SO3(g)
- Mole fraction of reactants increases
- Mole fraction of products increases
- Mole fraction remains the same

b. N2(g) + 2O2(g) ::equil:: 2NO2(g)
- Mole fraction of reactants increases
- Mole fraction of products increases
- Mole fraction remains the same

I know that if there are more moles of gas molecules on the products on the right, it will shift to the left and that if there are more moles of gas molecules of the reactants on the left, it will shift to the right.

Would half a mole still count, if so, then there would be 1 1/2 moles total for the reactants compared to a mole of SO3?

I'm still stuck on the second one, as I know how many moles there are on the reactants, but I can't tell if you just have to count 2 on the products or multiply. I think I'm overthinking it here.
Title: Re: Mole Fractions of Reactants and Products
Post by: Hunter2 on October 24, 2023, 04:10:07 PM
Principle of Le Chatelier. In case of volume changes check  where you have more molecules on reactant side or product side. In which direction will the equilibrium shift if there is more space for the molecules.
So now use it for the given reactions.
Title: Re: Mole Fractions of Reactants and Products
Post by: MilkyCar on October 25, 2023, 09:36:22 PM
I assume now the mole fraction of the reactants increases for part a, and the mole fraction of the reactants increases for part b. Correct?
Title: Re: Mole Fractions of Reactants and Products
Post by: Hunter2 on October 25, 2023, 09:53:22 PM
Correct