For the reaction shown, calculate how many grams of each product form when the following amounts of reactant completely react to form products. Assume that there is more than enough of the other reactant.
2Al(s)+Fe2O3(s)→Al2O3(s)+2Fe(l)

4.3 gAl

Question

For the reaction shown, calculate how many grams of each product form when the following amounts of reactant completely react to form products. Assume that there is more than enough of the other reactant. 
2Al(s)+Fe2O3(s)→Al2O3(s)+2Fe(l) 

4.3 gAl

matt101 · Answer

You need to use some stoichiometry here. The only way to do that is if you're working in moles. Since you're given grams of Al, you can convert that moles by dividing by the molar mass.

Then from looking at the coefficients in your equation, you can see that for however many moles of Al react, the same numbers of moles of Fe will be produced, but only half as many moles of Al2O3 will be produced.

To go back to grams, multiply the moles of each product that you get by their molar masses!