Right, so I'm not going to exactly provide the answer dzidza, but I'll try and use another question as an example of how to solve your types of questions.
3H
2 + N
2 2NH
3. Also written as: 3 mol hydrogen gas + 1 mol nitrogen gas
2 mol ammonia gas
Right, so an example question would be to determine how many litres of hydrogen gas at STP is required to produce 15 g of ammonia gas. Okay, so with every stoichiometry question the general premise is converting mol of 1 substance to mol of another substance (whether it be a product or reactant).
This mol-ratio is dependent upon the provided chemical equation. For example, the mol ratio required for this question is 3 mol H
2 = 2 mol NH
3, or 3 mol H
2 is required to produce 2 mol of NH
3.
Rightio, so, working from here, one simply converts mass of ammonia gas to mol ammonia gas (using molar mass), to mol hydrogen gas (using mol ratio), and finally to volume of hydrogen gas at STP (1 mol = 22.4L).
The calculations look something like this:
15 g NH
3 × (1mol NH
3/17.0 g NH
3) × (3mol H
2/2mol NH
3) × (22.4L H
2/1mol H
2) = 30L of H
2Always answer with a worded answer:
"As such, 30 litres of hydrogen gas is required to produce 15.0 g of ammonia gas."In this case, I use dimensional analysis (it's just easier for me), but the way of answering these kinds of questions require similar variations to the working-out above.
The way to work out your provided questions are similar to the method used above, however, it just requires a few more steps (like doing something with that molarity).
I hope this helps
KungKemi