[australia]

find the concentration in moles per liter( mol L^-1) and in grams per liter( gL^-1) of the original undiluted cerium sulfate solution?

H2O2 + 2 H^(1+) +2Ce^(2+) ====> 2H2O + 2Ce^(3+)

A solution of cerium (II) sulfate was analysed by the following steps:
I) 50.00 mL of the solution was diluted to 500.0 mL in the volumetric flask
ii) 20.00 mL of diluted solution was pipetted into a conical flask
iii) about 20 mL of dilute sulfuric acid was added to the flask
iv) standardised hydrogen peroxide solution of concentration was delivered from a burette
v) 35.45 mL of the hydrogen peroxide was required to complete the reaction

[Unknown008]

You need to work 'backwards'.

1. Find the number of moles of hydrogen peroxide used to react with Ce^2+.

Number of moles = Concentration of H2O2 x Volume of H2O2

Be careful about the units!

2. Find the number of moles of Ce^2+ present in your conical flask, using the mole ratio given in your equation.

3. Find the number of moles of H2O2 in your initial 500 mL solution.

4. Hence, find the number of moles of Ce^2+ present in the 50 mL sample.

5. Calculate the concentration of Ce^2+ using 4, in mol/L

6. Find this concentration in g/L.

Post what you get! :)