J.R. S. answered 09/26/18
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You need to find out which is the limiting reactant. Is it Al(s), KOH(aq) or H2SO4(aq). To do this, you need to balance all the equations. Can you do that?
After balancing, find moles of each. For Al, it will be 1.01 g/atomic mass of Al
For KOH, it will be 0.050 Lof KOH x the molar concentration (you didn't provide this information)
For H2SO4 it will be 21 ml x density / molar mass of H2SO4 (you didn't provide the density). Or if you are given the molarity, you can find moles using that value (0.021 L x mole/L = moles)
For H2O it will be moles determined in the balanced equation.
Once you have moles of each, divide those values by the corresponding coefficients in the balanced equation that uses that substance. The one that has the lowest value is limiting.
Based on the limiting reactant, you can then find the theoretical moles of KAl(SO4)2*12H2O
From moles, you can find grams by using the molar mass of the alum.
Finally, for % yield, it will be actual yield (12.77g) divided by the theoretical yield (x100%).

J.R. S.
tutor
Sorry. I don’t understand your question. If I think I know what you’re asking, then my answer is only the H2O that appears as a reactant in the first and last equation. But I’m not sure I understand the question.
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09/26/18
Daisy S.
So once I balance out all my equations, and found the moles of each compound, would I need to divide coefficients of Reaction 1 and 4?
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09/26/18
Daisy S.
Nevermind, I figured it out! Thank you for the help!
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09/26/18
Daisy S.
09/26/18