# Chemsitry - Moles Consumed

by wcbryant87
Tags: chemsitry, consumed, moles
 P: 14 1. The problem statement, all variables and given/known data The overall chemical equation for the titration reaction is: OCl(aq) + 2 S2O3(aq) + 2H+(aq) 6 Cl(aq) + S2O6(aq) + H2O(R) If a titration requires 5.29 ml 0.256 M Na2S2O3, (i) how many moles of S2O32&(aq) were consumed in the titration, and (ii) how many moles of OCl&(aq) were in the sample? 2. Relevant equations 3. The attempt at a solution Ok so what i did was take .245/52.9 and multiplied it by 2 to get .0096 moles of S2O3 consumed....is that right?
 Admin P: 21,706 No. Try to explain what you did and why. And using numbers that were given in the question won't hurt.
 P: 14 I just realized there is supposed to be an arrow in between the 2H and the Cl; that is where the equation splits into reactants and products. I'm looking over it again and trying something different. I messed up in the math the first go around .256/.00529 L = 48.4 mols X 2 (because there are 2 mols S2O3) and that gives me 96.8 mols S2O3; part i Shouldn't part (ii) just be the 48.4 mols from the previous?
Admin
P: 21,706

## Chemsitry - Moles Consumed

You are still wrong. Check your units.
 P: 14 M = mols/volume I know M and the volume, so it should be M * volume..not divided..right? .256 * .00529 = .00135 .00135 * 2 = .0027 mols. Is that right?
 Admin P: 21,706 Better, but still wrong. You got concentration&volumes&moles part right. Why do you multiply by two if you are calculating number of moles of S2O32-?
 P: 14 I multiplied by 2 because there are 2 S2O3 in the equation. Doesn't that mean you multiply it by two so that your ratio is correct?
 Admin P: 21,706 Think about it - you put a mole of substance into the baker, but as reaction equation have a 2 in the equation, that means you put 2 moles in the baker? That's what you did now.

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