$$\text{2NaCl} \rightarrow \text{2Na} + \text{Cl}_2$$

$$2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}$$

Question 1

Which of the following best describes a chemical change?

Accepted Answer

A substance reacts with another to form a new substance with different properties.

Question 2

Which of the following is NOT one of the seven diatomic elements?

Accepted Answer

C$$_2$$

Question 3

What is the main difference between ionic and covalent bonds?

Accepted Answer

Ionic bonds involve the transfer of electrons, while covalent bonds involve the sharing of electrons.

Question 4

In the formation of sodium chloride (NaCl), how many electrons are transferred from sodium to chlorine?

Accepted Answer

$$1$$

Question 5

How many shared electrons are present in a molecule of carbon monoxide (CO)?

Accepted Answer

$$4$$

Question 6

Which statement about energy and chemical bond formation is correct?

Accepted Answer

Forming a chemical bond releases energy.

Question 7

In a chemical equation, what does the symbol $$(aq)$$ represent?

Accepted Answer

A substance is dissolved in water (aqueous).

Question 8

How many atoms are present in one molecule of Ca(NO$$_3$$)$$_2$$?

Accepted Answer

$$10$$

Question 9

Balance the following equation: \$$ 	ext{Al} + 	ext{O}_2 ightarrow 	ext{Al}_2	ext{O}_3 \. $$What are the correct coefficients?

Accepted Answer

$$4, 3, 2$$

Question 10

Which of the following best describes activation energy?

Accepted Answer

The minimum energy required to start a chemical reaction.

Question 11

Which of the following reactions is exothermic?

Accepted Answer

Combustion of methane in a stove.

Question 12

Which energy diagram correctly represents an endothermic reaction?

Accepted Answer

The products have higher energy than the reactants.

Question 13

Which of the following is a decomposition reaction?

Accepted Answer

$$	ext{2NaCl} ightarrow 	ext{2Na} + 	ext{Cl}_2$$

Question 14

Write the balanced equation for the reaction: Hydrogen gas reacts with oxygen gas to form water.

Accepted Answer

$$2	ext{H}_2 + 	ext{O}_2 ightarrow 2	ext{H}_2	ext{O}$$

Question 15

Which statement correctly describes the difference between acids and bases?

Accepted Answer

Acids have a high concentration of H$$^+$$ ions, while bases have a high concentration of OH$$^-$$ ions.

Question 16

A solution has a pH of 3. Which statement is true about this solution?

Accepted Answer

It has a high concentration of H$$^+$$ ions and is acidic.

Question 17

If a chemical reaction occurs in a living cell, which of the following is most likely true?

Accepted Answer

It is a chemical change, such as cellular respiration.

Question 18

Which of the following best describes a double displacement reaction?

Accepted Answer

$$	ext{AB} + 	ext{CD} ightarrow 	ext{AD} + 	ext{CB}$$

Question 19

A student mixes hydrochloric acid (HCl) with sodium hydroxide (NaOH). Which type of reaction occurs?

Accepted Answer

Neutralization

Question 20

Which of the following statements about the pH scale is correct?

Accepted Answer

A solution with pH 7 is neutral.

General Chemistry: Chemical Reactions, Bonding, and Acids/Bases – Study Guide

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