Q: Which of the following reactions is a decomposition reaction?

$$\text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2$$

Q: Which of the following is the correct formula for calculating the percent yield of a chemical reaction?

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

Q: Which of the following is the correct equation for the ion-product constant of water, $$K_w$$?

$$K_w = [\text{H}_3\text{O}^+][\text{OH}^-]$$

Question 1

A sample of water contains 18.02 g of H2O. How many molecules of water are present in this sample?

Accepted Answer

Question 2

Which of the following best describes the Law of Conservation of Mass as it applies to chemical reactions?

Accepted Answer

The total mass of reactants equals the total mass of products in a closed system.

Question 3

Which of the following reactions is a decomposition reaction?

Accepted Answer

$$	ext{CaCO}_3 ightarrow 	ext{CaO} + 	ext{CO}_2$$

Question 4

A 0.20 M solution of CaCl2 is prepared. What is the concentration of chloride ions, $$[	ext{Cl}^-]$$, in the solution?

Accepted Answer

$$0.40\ 	ext{M}$$

Question 5

Which of the following compounds will exhibit hydrogen bonding between its molecules?

Accepted Answer

$$	ext{NH}_3$$

Question 6

A gas occupies 2.0 L at 1.0 atm and 300 K. What will its volume be at 2.0 atm and 400 K? (Use the Combined Gas Law.)

Accepted Answer

$$V_2$$ = \frac{$$P_1$$ $$V_1$$ $$T_2$$}{$$T_1$$ $$P_2$$} = \frac{(1.0)(2.0)(400)}{(300)(2.0)} = 1.33\ 	ext{L}$$

Question 7

Which of the following best explains why warm soda loses its fizz faster than cold soda?

Accepted Answer

Gas solubility in water decreases as temperature increases.

Question 8

A solution is prepared by dissolving 5.0 g of NaCl in enough water to make 100.0 g of solution. What is the mass percent of NaCl in the solution?

Accepted Answer

$$5.0\%$$

Question 9

Which of the following is a correct statement about strong acids?

Accepted Answer

Strong acids completely ionize in water.

Question 10

Which of the following is the correct formula for calculating the percent yield of a chemical reaction?

Accepted Answer

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

Question 11

A 0.250 L sample of 1.50 M NaCl solution contains how many moles of NaCl?

Accepted Answer

$$0.375\ 	ext{mol}$$

Question 12

Which of the following best describes a precipitation reaction?

Accepted Answer

A reaction in which two aqueous solutions form an insoluble solid.

Question 13

Which of the following is the correct equation for the ion-product constant of water, $$K_w$$?

Accepted Answer

$$K_w = [	ext{H}_3	ext{O}^+][	ext{OH}^-]$$

Question 14

A solution has a pH of 3.25. What is its pOH at 25$$^\circC$$?

Accepted Answer

$$10.75$$

Question 15

Which of the following best describes the difference between intermolecular forces and chemical bonds?

Accepted Answer

Chemical bonds hold atoms together within a molecule, while intermolecular forces attract separate molecules.

Question 16

Which of the following is a property of gases explained by the kinetic molecular theory?

Accepted Answer

Gas particles are in constant random motion and their collisions with container walls create pressure.

Question 17

A 4.0 g sample of H2 reacts with excess O2 to form water according to $$2	ext{H}_2 + 	ext{O}_2 ightarrow 2	ext{H}_2	ext{O}. $$What is the theoretical yield of H2O in grams?

Accepted Answer

$$35.7\ 	ext{g}$$

Question 18

Which of the following is a correct statement about the solubility of ionic compounds in water?

Accepted Answer

All chlorides are soluble except those of Ag+, Pb2+, and $$Hg2^2+.$$

Question 19

Which of the following is the correct formula for calculating the pH of a solution?

Accepted Answer

$$	ext{pH} = -\log[	ext{H}_3	ext{O}^+]$$

Introductory Chemistry Final Exam Active Recall Study Guide – Step-by-Step Guidance

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