5.i #11

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Marco Morales 2G
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5.i #11

Postby Marco Morales 2G » Thu Jan 07, 2021 8:45 pm

So for the answer for 5.i #11, the textbook states Q=6.9
I was wondering where that number came from because when I do the reaction quotient formula (P / R), the product is (SO3)^2 and the reactants are ([SO2]^2 * [O2]) and after plugging in their respected concentrations ([0.10]^2 / [1.20]^2 * [0.50]), I get 0.0138. Can someone explain what I might've done wrong?

Jagveer 1I
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Re: 5.i #11

Postby Jagveer 1I » Thu Jan 07, 2021 8:54 pm

The moles are given in mmol and the volume is 0.5L, so the concentration needs to be calculated with that information accounted for. I got [SO3]=2x10^-4, [SO2]=0.0024, [O2]=0.001. After using those values I got the answer of 6.9. Hope this helps.

Sabina House 2A
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Re: 5.i #11

Postby Sabina House 2A » Thu Jan 07, 2021 8:57 pm

Before you plug the values into the equation, you must convert them into moles/L. They start by giving you the values in mmol and give you the volume of 0.500 L so you must convert the mmol to mol and then divide that value by 0.500 L for each. That should give you the correct answer.

Marcus Lagman 2A
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Re: 5.i #11

Postby Marcus Lagman 2A » Thu Jan 07, 2021 8:59 pm


In order to find the reaction's quotient (Q) at 700 K, you must figure out the reaction's formula. You are correct on where the products and reactants would go in the formula, so you would have [SO3]^2 / [SO2]^2*[O2].

You would then convert the given values to molar concentrations:
All the millimoles would be converted into moles (1.0*10^-4 mols SO3, 0.0012 mols SO2, and 5.0*10^-4 mols O2)

Then divide all the moles to the given liter, 0.5L, to obtain the molar concentrations (2.0*10^-4 mol/L SO3, 0.0024 mol/L SO2, and 0.001 mol/L O2)

After finding all the molar concentrations, you would then plug it into the formula and find the answer to be 6.9

I hope this helps!

Andrew Yoon 3L
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Re: 5.i #11

Postby Andrew Yoon 3L » Thu Jan 07, 2021 10:18 pm

You have to change mmol to mol/L. First change to mmol to mol and then divide by volume (L) to get the molarity.

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