Question

How many grams of hydrogen gas (don't forget it's diatomic) can be produced when 5.45 g of iron reacts with excess HCI? 2Fe(s) + 6HCl(aq) --> 2FeCl3(aq) + 3H2 (g)

Answer 1

Answer: 0.295g

Explanation: The answer is 0.295g. Normally you would start by checking which of your reactants is the limiting reactant, but since you have excess HCl, you don't need to worry about that. Start by converting grams of iron to moles (done by dividing grams by iron's molar mass).

Next, you convert moles Fe to moles H2 by checking the coefficients in front of Iron and H2. Divide by iron's coefficient and multiply by H2's

Finally, you multiply by the molar mass of H2. To find it, multiply the molar mass of hydrogen by 2.

Easy way to read it:
5.45/44.845 x 3/2 x 2(1.008) = 0.295