Just follow the steps in this worked example.
http://www.jiskha.com/science/chemistry/stoichiometry.html
Hydrogen Peroxide decomposes to produce oxygen gas and water, What mass of hydrogen peroxide (H2O2) nust decompose to produce 0.77 grams of water?
3 answers
1. Write a balanced equation :
2H^2O^2---O^2+ 2H^2O
2. Find the molar mass (g/mol) of each:
34.02 32.00 18.02
3. Divide grams water by the molar mass of water:
.77g (1mol/18.02g) ~ .0427 mols
4. Use the mole ratios to find the number of hydrogen peroxide moles:
2H^2O^2---O^2+ 2H^2O; they are the same.
5. Multiply moles by molar mass of hydrogen peroxide.
.0427 mol (34.02g/1mol)
6. Answer
1.454g H^2O^2
2H^2O^2---O^2+ 2H^2O
2. Find the molar mass (g/mol) of each:
34.02 32.00 18.02
3. Divide grams water by the molar mass of water:
.77g (1mol/18.02g) ~ .0427 mols
4. Use the mole ratios to find the number of hydrogen peroxide moles:
2H^2O^2---O^2+ 2H^2O; they are the same.
5. Multiply moles by molar mass of hydrogen peroxide.
.0427 mol (34.02g/1mol)
6. Answer
1.454g H^2O^2
thanks bae
1 answer