Question 1

Which of the following best describes why sodium (Na) and chlorine (Cl) form an ionic bond to create sodium chloride (NaCl)?

Accepted Answer

Sodium donates an electron to chlorine, resulting in oppositely charged ions that attract each other.

Question 2

Which property of water allows trees to transport water from their roots to their leaves against gravity?

Accepted Answer

Cohesion and adhesion due to hydrogen bonding

Question 3

A radioactive isotope of carbon, $$^{14}C$$, is used in radiocarbon dating. What makes $$^{14}C$$ different from the most common carbon isotope, $$^{12}C$$?

Accepted Answer

$$^{14}C$$ has more neutrons than $$^{12}C$$

Question 4

Which of the following statements about pH is correct?

Accepted Answer

A solution with a pH of 7 has equal concentrations of H$$^+$$ and OH$$^-$$ ions.

Question 5

Which of the following best explains why water is considered a 'universal solvent'?

Accepted Answer

Water's polarity allows it to dissolve many ionic and polar substances.

Question 6

A buffer system in blood helps maintain a stable pH. What would happen if a strong acid was added to blood without a buffer present?

Accepted Answer

The pH would decrease rapidly, potentially harming cellular function.

Question 7

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

Accepted Answer

Covalent bonds involve the sharing of electron pairs between atoms.

Question 8

Which element is the most abundant by weight in the human body?

Accepted Answer

Oxygen

Question 9

A molecule of methane (CH$$_4) is $$described as nonpolar. What does this mean about the distribution of electrons in the molecule?

Accepted Answer

Electrons are shared equally, resulting in no partial charges.

Question 10

Which of the following best describes the difference between a cation and an anion?

Accepted Answer

A cation is positively charged, while an anion is negatively charged.

Question 11

Which of the following is an example of a reversible chemical reaction?

Accepted Answer

$$\mathrm{CO}_2 + \mathrm{H}_2\mathrm{O} \rightleftharpoons \mathrm{H}_2\mathrm{CO}_3$$

Question 12

Which of the following best explains why geckos can climb smooth surfaces?

Accepted Answer

They use van der Waals interactions between their toe pads and the surface.

Question 13

Which of the following is true about hydrogen bonds?

Accepted Answer

They are weak bonds that form between a hydrogen atom and an electronegative atom like oxygen or nitrogen.

Question 14

Which of the following best describes a solution?

Accepted Answer

A mixture where substances are evenly distributed and dissolved.

Question 15

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

Accepted Answer

The carbonic acid-bicarbonate system

Question 16

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

Accepted Answer

Hydrogen bonds in ice hold water molecules farther apart, making ice less dense.

Question 17

Which of the following is NOT a trace element in the human body?

Accepted Answer

Oxygen (O)

Question 18

Which of the following best describes the relationship between structure and function in biological molecules?

Accepted Answer

The structure of a molecule determines how it interacts and functions in living systems.

Question 19

Which of the following is an example of a polar covalent bond?

Accepted Answer

The bond between oxygen and hydrogen in a water molecule

Question 20

Which of the following best explains why morphine can mimic the effects of endorphins in the brain?

Accepted Answer

Morphine has a similar molecular structure to endorphins, allowing it to bind to the same receptors.

The Chemical Basis of Life: Atoms, Bonds, and Water

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