# Molarity homework problem

TypeFun

## 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

## Answers and Replies

Homework Helper
Gold Member

Keep trying.

TypeFun

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.

TypeFun

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

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.

TypeFun

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?

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.

TypeFun

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

Homework Helper