Q: A solution has a pH of 4. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

$$[H^+] = 1 \times 10$$^{-4}$$ \ \mathrm{M}$$

Question 1

Which of the following statements best explains why water is an excellent solvent for biological reactions?

Accepted Answer

Water is highly polar, allowing it to form hydrogen bonds with ions and polar molecules.

Question 2

A radioactive isotope of carbon, carbon-14, is used in radiometric dating. What makes carbon-14 different from the most common carbon isotope, carbon-12?

Accepted Answer

Carbon-14 has more neutrons than carbon-12.

Question 3

Which of the following best describes the difference between a covalent bond and an ionic bond?

Accepted Answer

Covalent bonds involve the sharing of electrons, while ionic bonds involve the transfer of electrons.

Question 4

Which property of water is primarily responsible for the movement of water from the roots to the leaves of plants against gravity?

Accepted Answer

Cohesion and adhesion

Question 5

A solution has a pH of 4. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-4}$$ \ \mathrm{M}$$

Question 6

Which of the following functional groups acts as a base by attracting protons in solution?

Accepted Answer

Amino group

Question 7

Why does ice float on liquid water?

Accepted Answer

Ice is less dense than liquid water due to its open crystal structure formed by hydrogen bonds.

Question 8

Which of the following best describes a spontaneous chemical reaction?

Accepted Answer

A reaction that proceeds without continuous external influence, often resulting in increased entropy or lower potential energy.

Question 9

Which of the following statements about electronegativity is correct?

Accepted Answer

Oxygen is more electronegative than nitrogen.

Question 10

A molecule of methane ($$CH_4) $$has which of the following molecular geometries?

Accepted Answer

Tetrahedral

Question 11

Which of the following is a real-world example of a condensation (dehydration) reaction?

Accepted Answer

The formation of a peptide bond between two amino acids, releasing a molecule of water.

Question 12

Which of the following best explains why nonpolar molecules do not dissolve in water?

Accepted Answer

Nonpolar molecules lack partial charges and cannot interact with water’s polarity.

Question 13

Which of the following is true about the first law of thermodynamics?

Accepted Answer

Energy is conserved and can only be transferred or transformed.

Question 14

Which of the following best describes the role of buffers in biological systems?

Accepted Answer

Buffers minimize changes in pH, helping maintain homeostasis.

Question 15

Which of the following statements about chemical evolution is supported by Stanley Miller’s 1953 experiment?

Accepted Answer

Simple molecules with high free energy can form complex organic molecules when exposed to energy.

Question 16

Which of the following functional groups is most likely to form disulfide bonds in proteins?

Accepted Answer

Sulfhydryl group

Question 17

If a molecule has two unpaired electrons in its valence shell, how many covalent bonds can it typically form?

Accepted Answer

Two

Question 18

Which of the following best describes the relationship between entropy and spontaneous chemical reactions?

Accepted Answer

Spontaneous reactions tend to increase entropy in the system.

Question 19

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

Accepted Answer

The bond between oxygen and hydrogen in $$H_2O$$

Question 20

Which of the following statements about organic molecules is correct?

Accepted Answer

Organic molecules always contain carbon bonded to hydrogen and may include other elements.

Water and Carbon: The Chemical Basis of Life (General Biology Study Notes)

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드