Theoretical yield... (asking as the txtbook doesnt explain!!)?

Question

I have this kind of reaction:

2Mn + 2O2 = 2MnO2

find the theoretical yield of product in mol

if... Mn - 3 mol O2 - 3 mol

I know how to do if the given is in grams, but not in moles.

Can someone please help!! Thank you very much!!

Answer 1

Theoritical yield is basically the amount of products obtained according to the reaction. So in that equation the theoretical yield would be  2 Moles of MnO2.

When given in grams, you just convert them into moles.

Example

110 g Mn for this reaction

110g x (1mol/55g) x (1 mol MnO2/ 1 mol Mn) = 2 mol MnO2

Your theoretical yield is 1 mol MnO2

in grams:

2 mol MnO2 x (87 g/mol)= 174 g MnO2

Answer 2

From your balanced equation:

2Mn + 2O2 → 2MnO2

2moles Mn + 2 moles O2 yields 2moles MnO2

Therefore:

3 moles Mn + 3 moles O2 yields 3 moles MnO2

Molar mass MnO2 = 54.938 + 15.999+ 15.999 = 86.936g

3 moles of MnO2 = 3*86.936 = 260.808g

Theoretical yield = 260.808 g.

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