How to go from mole-mole an..

Please help me with these problems and briefly explain how you received the answers. Thank you so much!

mole-mole

Using this balanced equation: 2H2 + O2 --> 2H20

a) 10 moles of H2 --> moles of O2

I don't know how to this one because I do not see an O2 on the right side of equation. Teacher must have printed it incorrectly.

b) 15 moles of O2 --> moles of H2O

I got 30 moles of H20. correct?

gram-gram

Li + Cl2 --> LiCl

a) Given 10 grams of Chlorine determine grams of Lithium chloride.

a) Maybe, your teacher is asking you to find out how many moles of oxygen is required to react with 10 moles of hydrogen. In that case, you will need 5 moles of oxygen.

b) Yup, you're right about this one =)

a) first, we will need to find the relative molecular mass of Cl2, which is 35.5 x 2 = 71

Now, we find out how many moles of chlorine is present in 10 g of it:

No. of moles of chlorine = 10/71 = 0.14085 moles

Since the ratio of moles between chlorine and lithium chloride is 1:1, so, we expect 0.14085 moles of LiCl to be produced.

The relative molecular mass of LiCl is 6.9 + 35.5 = 42.4

So, the mass of LiCl produced is 0.14085 x 42.4 = 5.97 g (Ans)

No, she printed it correctly Mols are ratios and can be ratios of reactants, as well as products. Just use the ratio. Here is the dimensional analysis set up.

10 mol X 1mol O2/2mol H2 = 5 mol O2

B is correct.

The chlorine problem. I am going to estimate grams of Cl2.

10 grams Cl2 X 1mol Cl2/70.9g Cl2 X 42.39g LiCl/1mol LiCl

= 5.98 grams LiCl

You look up exact weights on your periodic table, as I am going from memory.

Yes you should balance the equation. Good catch. You will do well in chemistry when you need to make your own equations. So, now just change the mol ratio.