Question 1

Which of the following best explains why atoms are electrically neutral under normal conditions?

Accepted Answer

They have equal numbers of protons and electrons.

Question 2

A sodium atom (Na) has an atomic number of 11 and a mass number of 23. How many neutrons does it have?

Accepted Answer

$$23 - 11 = 12$$ neutrons

Question 3

Which of the following statements about isotopes is correct?

Accepted Answer

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

Question 4

Which type of bond is formed when two atoms share electrons equally?

Accepted Answer

Nonpolar covalent bond

Question 5

A solution has a pH of 4. How many times more acidic is it than a solution with a pH of 7?

Accepted Answer

$$10^{(7-4)} = 1000$ times more acidic

Question 6

Which of the following best describes the process of hydrolysis?

Accepted Answer

The breakdown of large molecules by the addition of water

Question 7

Which functional group is represented by the formula $$\mathrm{COOH}$$?

Accepted Answer

Carboxyl group

Question 8

If an atom has 8 protons, 8 neutrons, and 10 electrons, what is its net charge?

Accepted Answer

$$8 - 10 = -2$$; the atom has a $$2^-$$ charge

Question 9

Which of the following best explains why water is a polar molecule?

Accepted Answer

Oxygen is more electronegative than hydrogen, creating a partial negative charge near the oxygen atom and a partial positive charge near the hydrogen atoms.

Question 10

Which of the following is a correct statement about hydrogen bonds?

Accepted Answer

They are weak attractions between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom.

Question 11

Which of the following best describes an exergonic reaction?

Accepted Answer

A reaction that releases free energy to its surroundings

Question 12

A carbon atom has 6 protons, 6 neutrons, and 6 electrons. How many valence electrons does it have?

Accepted Answer

4

Question 13

Which of the following best explains why buffers are important in biological systems?

Accepted Answer

They help maintain a relatively constant pH by accepting or donating hydrogen ions.

Question 14

Which of the following is the best example of a real-world application of the first law of thermodynamics in biology?

Accepted Answer

Plants converting light energy into chemical energy during photosynthesis

Question 15

Which of the following best describes the difference between kinetic and potential energy in a biological context?

Accepted Answer

Kinetic energy is the energy of motion, such as molecules moving, while potential energy is stored energy, such as energy stored in chemical bonds.

Question 16

Which of the following best describes the role of electrons in chemical bonding?

Accepted Answer

Electrons in the outermost shell (valence electrons) are involved in forming chemical bonds.

Question 17

Which of the following is a correct statement about ionic bonds?

Accepted Answer

They are formed when one atom donates an electron to another atom, resulting in oppositely charged ions that attract each other.

Question 18

Which of the following best explains why water has a high specific heat capacity?

Accepted Answer

Hydrogen bonding between water molecules requires more energy to change temperature.

Question 19

A solution contains more hydroxide ions ($$\mathrm{OH^-}) $$than hydrogen ions ($$\mathrm{H^+}). $$Which of the following best describes the solution?

Accepted Answer

The solution is basic (alkaline).

General Biology: Atomic Structure, Chemical Bonds, and Properties of Water

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