Question 1

Which of the following best describes an isotope of an element?

Accepted Answer

An atom with the same number of protons but a different number of neutrons.

Question 2

Which property of water allows insects like water striders to walk on its surface?

Accepted Answer

Cohesion due to hydrogen bonding

Question 3

A solution has a hydrogen ion concentration of $$1 	imes 10$$^{-6}$$ M. What is its pH?

Accepted Answer

$$pH = 6$$

Question 4

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

Accepted Answer

Hydrogen bonds between water molecules require more energy to break.

Question 5

Which statement about covalent bonds is correct?

Accepted Answer

Covalent bonds are formed when atoms share pairs of electrons.

Question 6

What is the atomic number of an atom with 8 protons, 8 neutrons, and 8 electrons?

Accepted Answer

8

Question 7

Which of the following is a real-life example of a buffer system in the human body?

Accepted Answer

The carbonic acid-bicarbonate system in blood

Question 8

Which of the following best describes electronegativity?

Accepted Answer

The likelihood of an atom to attract shared electrons in a covalent bond.

Question 9

If an atom has a filled valence shell, what is its chemical reactivity?

Accepted Answer

It is chemically stable and unreactive.

Question 10

Which of the following is a consequence of water's polarity?

Accepted Answer

Water can dissolve many ionic and polar substances.

Question 11

A scientist mixes NaCl in water. What type of bond is broken when NaCl dissolves?

Accepted Answer

Ionic bonds between Na$$^+$$ and Cl$$^-$$

Question 12

Which of the following best describes the difference between polar and nonpolar covalent bonds?

Accepted Answer

Polar covalent bonds involve unequal sharing of electrons due to differences in electronegativity.

Question 13

Which property of water is most important for regulating Earth's climate?

Accepted Answer

High specific heat

Question 14

What is the mass number of an atom with 12 protons and 13 neutrons?

Accepted Answer

25

Question 15

Which of the following is true about hydrogen bonds?

Accepted Answer

They occur between a hydrogen atom covalently bonded to O, N, or F and another electronegative atom.

Question 16

Which of the following best explains why ice floats on water?

Accepted Answer

Hydrogen bonds in ice create a lattice that spaces molecules farther apart, lowering density.

Question 17

Which of the following is a function of a buffer in biological systems?

Accepted Answer

Buffers help maintain the homeostasis of the acid-base balance.

Question 18

Which of the following is the best definition of a solute?

Accepted Answer

The substance that is dissolved in a solution.

Question 19

How many electrons are present in the first shell of an atom?

Accepted Answer

2

Question 20

Which of the following best describes adhesion?

Accepted Answer

The attraction between molecules of different substances.

Chapter 2: The Chemical Context of Life – General Biology Study Notes

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