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### Calculate number of moles of `H_2O_2`

Posted: Sun 10 April, 2011 01:20
Calculate number of moles of `H_2O_2` (hydrogen peroxide) used?
concentration of H2O2 (aq) is `(3.01 g)/(100ml)`
volume of H2O2 (aq) used is 150 ml

molar mass of `H_2O_2` is `(34.016g)/(mol)`

### Re: Calculate number of moles of `H_2O_2`

Posted: Sun 10 April, 2011 01:34
we have 150ml or 0.15L of `H_2O_2` and in this 0.15L we have `(3.01 g)/(100ml)`

First find out how many gram we got in total. We have `(3.01 g)/(100ml)=(3.01 g)/(0.1L)` so in 0.15L how many grams?
`(3.01 g)/(0.1L)*0.15L=4.515g`
now we know that we got 4.515g of `H_2O_2`

To find number of moles, we use the molar mass from periodic table `(34.016g)/(mol)` to find the mols
`(34.016g)/(mol)=(4.515g)/(x)` solve for x first by cross multiplying
`34.016g*x=4.515g*(mol)` now divide both side by 34.016g `(34.016g*x)/(34.016g)=(4.515g*(mol))/(34.016g)` the 34.016g on the left cancels out and we have:
`x=(4.515g*(mol))/(34.016g)=0.13273mol`

so 0.13273mol of `H_2O_2` has been used.