# Molarity homework problem

## Homework Statement

Calculate the initial molarity of S2O32- in each trial given that each trial has 1.00 mL of .010 M Na2S2O3 and a total volume of 7.00 mL.

mol = g/(g/mol)
M1V1=M2V2

(1)(.01)=7x
.0014=x

## The Attempt at a Solution

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chemisttree
Homework Helper
Gold Member

Keep trying.

Hmm. Well that's really not that helpful to me. Do you have a hint on what I should do? I mean, I wouldn't be asking on this forum if I wasn't in need of help.

Can anyone help me out with this? I'm stuck.

symbolipoint
Homework Helper
Gold Member

Easier to use the definition of molarity. How many moles compound in each trial? How much volume of finished solution in each trial? Calculate the ratio.

How many moles compound in each trial? How much volume of finished solution in each trial? Calculate the ratio.
It does not give the number of moles per trial. The question written above is all the information given.

The total volume is 7.00 mL. Is that how much volume of finished solution would be in each trial?

symbolipoint
Homework Helper
Gold Member

The total volume is 7.00 mL. Is that how much volume of finished solution would be in each trial?
Yes.

I'm still struggling.
I've calculated the grams of Na2S2O3 = 1.58 g, but I'm still confused as to how I get the molarity of S2O3

symbolipoint
Homework Helper