Q: If a reaction has a theoretical yield of 50 grams and an actual yield of 40 grams, what is the percent yield?

$$\frac{40}{50} \times 100 = 80\%$$

Q: In a laboratory experiment, a student determines the actual yield of a product to be 15 grams, while the theoretical yield is 20 grams. What is the percent yield?

$$\frac{15}{20} \times 100 = 75\%$$

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

$$\% \text{ yield} = \frac{\text{actual yield}}{\text{theoretical yield}} \times 100$$

Q: A reaction produces 8 grams of product, but the theoretical yield is 10 grams. What is the percent yield?

$$\frac{8}{10} \times 100 = 80\%$$

Question 1

A chemical reaction is given by $$4 \mathrm{HCl} + \mathrm{O}_2 \rightarrow 2 \mathrm{H}_2\mathrm{O} + 2 \mathrm{Cl}_2. If $$you start with 20 moles of HCl and excess $$\mathrm{O}_2$$, how many moles of $$\mathrm{Cl}_2$$ will be produced?

Accepted Answer

10 moles

Question 2

In the reaction $$4 \mathrm{HCl} + \mathrm{O}_2 \rightarrow 2 \mathrm{H}_2\mathrm{O} + 2 \mathrm{Cl}_2$$, what is the limiting reactant if you have 8 moles of HCl and 3 moles of $$\mathrm{O}_2$$?

Accepted Answer

HCl

Question 3

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

Accepted Answer

The maximum amount of product that can be formed from the limiting reactant, calculated using stoichiometry.

Question 4

If a reaction has a theoretical yield of 50 grams and an actual yield of 40 grams, what is the percent yield?

Accepted Answer

$$\frac{40}{50} 	imes 100 = 80\%$$

Question 5

Given the reaction $$2 \mathrm{HCl} + \mathrm{Cl}_2 \rightarrow 2 \mathrm{HCl}_2$$, how many moles of $$\mathrm{HCl}_2$$ are produced from 22 moles of HCl?

Accepted Answer

11 moles

Question 6

A student mixes 2 crackers, 1 marshmallow, and 3 rectangles of chocolate to make s'mores. If they have 6 crackers, 2 marshmallows, and 9 rectangles of chocolate, what is the maximum number of s'mores they can make?

Accepted Answer

3

Question 7

Which statement about excess reactant is correct?

Accepted Answer

It does not limit the amount of product formed and some will remain after the reaction.

Question 8

In a laboratory experiment, a student determines the actual yield of a product to be 15 grams, while the theoretical yield is 20 grams. What is the percent yield?

Accepted Answer

$$\frac{15}{20} 	imes 100 = 75\%$$

Question 9

Which of the following is true about a limiting reactant in a chemical reaction?

Accepted Answer

It determines the maximum amount of product that can be formed.

Question 10

A reaction has the following balanced equation: $$2 \mathrm{A} + 3 \mathrm{B} \rightarrow 4 \mathrm{C}. If $$you start with 10 moles of A and 15 moles of B, what is the maximum number of moles of C that can be produced?

Accepted Answer

20 moles

Question 11

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

Accepted Answer

$$\% 	ext{ yield} = \frac{	ext{actual yield}}{	ext{theoretical yield}} 	imes 100$$

Question 12

A reaction produces 8 grams of product, but the theoretical yield is 10 grams. What is the percent yield?

Accepted Answer

$$\frac{8}{10} 	imes 100 = 80\%$$

Question 13

If a reaction is performed and both reactants are completely consumed, what can be said about the limiting reactant?

Accepted Answer

The reactant that produces the least amount of product is the limiting reactant.

Question 14

A student wants to produce 5 moles of $$\mathrm{Cl}_2$$ using the reaction $$4 \mathrm{HCl} + \mathrm{O}_2 \rightarrow 2 \mathrm{H}_2\mathrm{O} + 2 \mathrm{Cl}_2. $$How many moles of HCl are required?

Accepted Answer

10 moles

Question 15

Which of the following scenarios best illustrates the concept of a limiting reactant?

Accepted Answer

Making sandwiches with 10 slices of bread and 8 slices of cheese, where each sandwich requires 2 slices of bread and 1 slice of cheese.

Question 16

In a reaction, the actual yield is always:

Accepted Answer

Less than or equal to the theoretical yield.

Question 17

Which of the following is NOT a correct step in solving a stoichiometry problem?

Accepted Answer

Ignoring the balanced chemical equation.

Question 18

A reaction has a theoretical yield of 100 grams, but only 60 grams are obtained in the laboratory. What is the percent yield?

Accepted Answer

$$\frac{60}{100} 	imes 100 = 60\%$$

Question 19

Which term describes the reactant that is completely consumed first in a chemical reaction?

Accepted Answer

Limiting reactant

Chapter 4

Guida di studio - Domande di pratica

Study guide - Flashcard