Question

Fe2O3 + 3H2 → 2Fe + 3H2O
Calculate the mass of iron produced when 450.0 grams of iron (III) oxide react with hydrogen gas.
If you can please show me the work so I can learn how to do it

Answer 1

2 Fe = 2 * 56 = 112 grams / 2 mols
3 O = 3 * 16 = 48 g / 3 mols
so
Fe2O3 = 160 g/mol
so
450 g * ( 1 mol / 160 g) = 2.81 mols of iron oxide
That will give me 2 * 2.81 = 5.63 mols of Fe
5.63 * 56 g/mol = 315 grams of Fe

Answer 2

The work by Anonymous is quite right and is presented very well. Here is a set of instructions that will work any stoichiometry problem.
Step 1. Write and balance the equation.
Step 2. Convert what you have into moles. moles = grams/molar mass OR if it is a solution then moles = molarity x liters or M x L = ?
Step 3. Using the coefficients, as Anonymous did above, convert moles of what you have to moles of what you want.
Step 4. If you want grams, then grams = moles x molar mass = ?
Good luck.