Question

15.0g of each reactant is taken,determine which mass is limiting and calculate the mass of each product: Al(s)+HCl(aq)-->AlCl3(aq)+H2(g)

Answer 1

Balance the equation.

Convert 15.0 g Al to moles. moles = grams/molar mass.
Convert 15.0 g HCl to moles. Same procedure.

Convert moles Al to moles H2.
Convert moles HCl to moles H2.
It is likely you will obtain different answers which means one of them is wrong. The correct answer, in limiting reagent problems, is ALWAYS the smaller one and the reactant producing that value is the limiting reagent.

Take the smaller value of moles for H2 from above and convert to grams. g = moles x molar mass.

Using the coefficients in the balanced equation, convert moles of the limiting reagent to moles AlCl3. Then convert that to grams as above.