# Find theoretical yield from a balanced equation

• g-tar-man
In summary, you were able to calculate the theoretical yield of N2 from the mass of NaNO2 and the amount of N2 created experimentally. You then took the actual yield and divided it by the theoretical yield to get your percentage yield.
g-tar-man
I searched and wasn't able to find what I was looking for. I need to find the theoretical yield so I can find the percent yield, which I know how do to. I just can't remember how to find theoretical yield from a balanced equation. My equation which I believe to be correct is NaNO2+HSO3NH2=NaHSO4+H20+N2. Could you let me know what I need to do, thanks.

$$NaNO_{2} + HSO_{3}NH_{2} \rightarrow NaHSO_{4}+H_{2}O+N_{2}$$

Find the number of moles of each starting material
Determine the limiting reactant
Calculate the moles of product expected if the yield was 100% based on the limiting reactant
Convert moles to grams

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Ok I determined the moles of NaNO2 and determined that was the limiting reactant, I think. Because I was given the mass of NaNO2 to be .1120g I figured that to be .0016mol NaNO2. I'm not sure how to calculate the theoretical yield of N2 in mols. I also found mol N2 collected to be .00156 mol.

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If $$NaNO_{2}$$ is the limiting reactant, than the theoretical yield of $$N_{2}$$ is 0.0016 moles.

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I just need to find the theoretical yield of N2 in moles. I used the equation n=pv/rt to find mol N2, if that helps. We basically measured the volume of N2 gas by causing a reaction inside a test tub. When the gas was produced from the test tube the volume in the buret dropped and we moved a tube with a funnel and water down the buret to keep the pressure equal.

g-tar-man said:
I just need to find the theoretical yield of N2 in moles. I used the equation n=pv/rt to find mol N2, if that helps. We basically measured the volume of N2 gas by causing a reaction inside a test tub. When the gas was produced from the test tube the volume in the buret dropped and we moved a tube with a funnel and water down the buret to keep the pressure equal.
You've been given the theoretical yield of N2, and you know the actual yield from the experiment.

Percent yield = (Actual yield / Theoretical yield) x 100%

You can calculate this using moles.

g-tar-man said:
Ok I determined the moles of NaNO2 and determined that was the limiting reactant, I think. Because I was given the mass of NaNO2 to be .1120g I figured that to be .0016mol NaNO2. I'm not sure how to calculate the theoretical yield of N2 in mols. I also found mol N2 collected to be .00156 mol.
Firstly, ignore that you are trying to find out the percentage yield. This, it would seem, is changing the meaning of your question so much that you are not understanding.

I assume either you or a book reacted 0.1120g of NaNO2 and then, experimentally or because the book said so, you got a value for the amount of N2 created.

Now, just work out the mass of N2 created from 0.1120g, assuming the reaction is 100% efficient. This will give you the theoretical yield.

After this, take the value of N2 you actually got and divide it by the value you just calculated (but obviously with the same units). Then multiply by 100 to get your percentage yield.

I hope that all of the explanations have put a different light on the problem and that you start to understand it in your own way

I hope this helps.

Yes thanks, I was able to finish it this morning. I think I got the percent yield to be around 97%. So not to bad I guess. Thanks for your help. Sorry about posting in the wrong section. It just seemed like the right place to put it.

## 1. What is theoretical yield?

Theoretical yield is the maximum amount of product that can be obtained from a chemical reaction, assuming all reactants are completely converted to products and there are no side reactions or loss of product during the process.

## 2. How do you calculate theoretical yield?

Theoretical yield can be calculated using the balanced chemical equation, where the coefficients represent the mole ratio between reactants and products. Multiply the moles of the limiting reactant by the mole ratio of the desired product to find the theoretical yield in moles. This can then be converted to grams if needed.

## 3. What is the difference between theoretical yield and actual yield?

Theoretical yield is the calculated maximum amount of product, while actual yield is the amount of product obtained in a real experiment. Actual yield may be lower than theoretical yield due to experimental error, incomplete reactions, or other factors.

## 4. Why is it important to know the theoretical yield?

Knowing the theoretical yield allows for better planning and optimization of chemical reactions. It also helps in determining the efficiency of a reaction and identifying any potential issues or sources of error.

## 5. Can theoretical yield ever be greater than actual yield?

No, theoretical yield is a calculated maximum amount and cannot be exceeded in a real experiment. Actual yield may be lower due to various factors, but it cannot be higher than the theoretical yield.

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