Question 1

Which of the following statements best describes the modern atomic theory as it applies to the composition of atoms?

Accepted Answer

Atoms are composed of protons, neutrons, and electrons, with electrons occupying specific energy levels around the nucleus.

Question 2

An element has an atomic number of 17 and a mass number of 35. How many neutrons does it have?

Accepted Answer

$$35 - 17 = 18$$ neutrons

Question 3

Which of the following best explains why sodium (Na) reacts vigorously with water, while neon (Ne) does not?

Accepted Answer

Sodium has one electron in its outer shell, which it readily loses to achieve a stable configuration, while neon already has a stable, full outer shell.

Question 4

Which of the following compounds is ionic?

Accepted Answer

NaCl

Question 5

A patient is given a solution containing 0.9% NaCl (normal saline). What type of chemical bond holds the Na$$^+$$ and Cl$$^-$$ ions together in this solution?

Accepted Answer

Ionic bond

Question 6

Which of the following best describes a redox reaction?

Accepted Answer

A reaction in which electrons are transferred from one substance to another.

Question 7

Which of the following is the correct balanced equation for the neutralization of hydrochloric acid (HCl) with sodium hydroxide (NaOH)?

Accepted Answer

$$\mathrm{HCl} + \mathrm{NaOH} \rightarrow \mathrm{NaCl} + \mathrm{H}_2\mathrm{O}$$

Question 8

A student mixes solutions of silver nitrate (AgNO$$_3) $$and sodium chloride (NaCl) and observes the formation of a white solid. What type of reaction has occurred?

Accepted Answer

Precipitation reaction

Question 9

Which of the following statements about covalent and ionic compounds is correct?

Accepted Answer

Ionic compounds are formed by the transfer of electrons, resulting in positive and negative ions that attract each other.

Question 10

Which of the following best explains why water (H$$_2O) is a $$polar molecule?

Accepted Answer

The molecule has a bent shape and an unequal sharing of electrons, resulting in a partial negative charge near the oxygen atom.

Question 11

A solution is prepared by dissolving 10.0 g of NaCl in enough water to make 500 mL of solution. What is the molarity of the solution? (Molar mass of NaCl = 58.44 g/mol)

Accepted Answer

$$\frac{10.0\ \mathrm{g}}{58.44\ \mathrm{g/mol}} = 0.171\ \mathrm{mol}$$; $$\frac{0.171\ \mathrm{mol}}{0.500\ \mathrm{L}} = 0.342\ \mathrm{M}$$

Question 12

Which of the following best describes the role of a catalyst in a chemical reaction?

Accepted Answer

A catalyst speeds up the reaction by lowering the activation energy without being consumed.

Question 13

Which of the following is the correct electron configuration for a neutral atom of magnesium (Mg, atomic number 12)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$

Question 14

A sample of gas occupies 2.0 L at 1.0 atm pressure. If the pressure is increased to 4.0 atm at constant temperature, what will be the new volume of the gas? (Assume ideal gas behavior.)

Accepted Answer

$$P_1V_1 = P_2V_2$$; $$V_2$$ = \frac{P_1V_1}{$$P_2$$} = \frac{1.0\ \mathrm{atm} 	imes 2.0\ \mathrm{L}}{4.0\ \mathrm{atm}} = 0.5\ \mathrm{L}$$

Question 15

Which of the following is a correct statement about isotopes?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 16

Which of the following best explains why ionic compounds conduct electricity when dissolved in water?

Accepted Answer

The ions are free to move in solution, allowing them to carry electric current.

Question 17

A patient is experiencing acidosis. Which of the following best describes what is happening in their blood chemistry?

Accepted Answer

The pH of the blood is below 7.35.

Question 18

Which of the following is the best example of a redox reaction in the human body?

Accepted Answer

The conversion of glucose to carbon dioxide and water during cellular respiration.

Question 19

Which of the following statements about the periodic table is correct?

Accepted Answer

Elements in the same group have the same number of valence electrons.

Syllabus and Study Guide for General, Organic, and Biological Chemistry (GOB Chemistry)

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