Q: Which formula is used to calculate percent yield in a chemical reaction?

$$\frac{\text{Actual yield}}{\text{Theoretical yield}} \times 100\%$$

Question 1

Which formula is used to calculate percent yield in a chemical reaction?

Accepted Answer

$$\frac{	ext{Actual yield}}{	ext{Theoretical yield}} 	imes 100\%$$

Question 2

A student performs a reaction and obtains 8.5 g of product, while the theoretical yield is 10.0 g. What is the percent yield?

Accepted Answer

$$85\%$$

Question 3

In a reaction, 2.49 g of Ca$$_3(PO$_4$$)$$_2$$ reacts to produce 1.25 g of water. What is the percent yield of water if the theoretical yield is 1.47 g?

Accepted Answer

$$85.0\%$$

Question 4

Which of the following best describes the actual yield in a chemical reaction?

Accepted Answer

The amount of pure product actually obtained from the experiment.

Question 5

If a reaction has a percent yield of 63.1\%, what does this indicate about the efficiency of the reaction?

Accepted Answer

The reaction produced 63.1\% of the theoretical yield.

Question 6

A reaction between 4.5 g Zn and 70.1 g CuSO$$_4$$ produces 2.1 g Cu. What is the percent yield of Cu if the theoretical yield is 3.33 g?

Accepted Answer

$$63.1\%$$

Question 7

Which step is necessary to determine the percent yield after a chemical reaction?

Accepted Answer

Calculate both the actual and theoretical yields.

Question 8

Ammonia reacts with hydrazine to produce water. If 111.9 g NH$$_3$$ yields 52.32 g N$$_2H$_4$$ and the percent yield is 81.5\%, what is the theoretical yield of N$$_2H$_4$$?

Accepted Answer

$$64.2	ext{ g}$$

Question 9

The reduction of Fe$$_2O$_3$$ with H$$_2$$ produces Fe and H$$_2O. If 8.05 $$mol Fe is required and the reaction is 77\% complete, how many moles of Fe$$_2O$_3$$ are needed?

Accepted Answer

$$2.27	ext{ mol}$$

Question 10

Why is the theoretical yield often greater than the actual yield in laboratory experiments?

Accepted Answer

Because side reactions, incomplete reactions, and loss during purification can occur.

Question 11

Which of the following is NOT a reason for a low percent yield in a chemical reaction?

Accepted Answer

All reactants are completely converted to products.

Question 12

A chemist isolates 22.1 g Cu from a reaction of 4.5 g Zn with 70.1 g CuSO$$_4. If $$the theoretical yield is 35.0 g, what is the percent yield?

Accepted Answer

$$63.1\%$$

Question 13

In a reaction, the theoretical yield of a product is 25.0 g, but only 20.0 g is obtained. What is the percent yield?

Accepted Answer

$$80\%$$

Question 14

Which of the following best describes the percent yield?

Accepted Answer

A measure of the efficiency of a chemical reaction.

Question 15

If a reaction produces 10.0 g of product but the theoretical yield is 12.5 g, what is the percent yield?

Accepted Answer

$$80\%$$

Question 16

A reaction is considered to have an 'excellent' percent yield if the yield is:

Accepted Answer

$$\geq 90\%$$

Question 17

Which step is NOT part of calculating percent yield?

Accepted Answer

Calculating the molar mass of the solvent.

Question 18

If a reaction has a percent yield of 100\%, what does this mean?

Accepted Answer

The actual yield equals the theoretical yield.

Question 19

A reaction produces 5.0 g of product, but the theoretical yield is 10.0 g. What is the percent yield?

Accepted Answer

$$50\%$$

Question 20

Which of the following is a common misconception about percent yield?

Accepted Answer

Percent yield can be greater than 100\% due to calculation errors or impurities.

Percent Yield in Chemical Reactions: Concepts, Calculations, and Practice

Study Guide - Practice Questions

Study Guide - Flashcards