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

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

Question 1

Which of the following best explains why water has a high specific heat capacity, and why this property is important for living organisms?

Accepted Answer

Water's high specific heat is due to hydrogen bonding between molecules, which requires more energy to break, thus stabilizing temperatures in organisms and environments.

Question 2

A scientist is studying two isotopes of carbon: $$^{12}C$$ and $$^{14}C. $$Which statement correctly describes the difference between these isotopes?

Accepted Answer

$$^{12}C$$ and $$^{14}C$$ have the same number of protons but different numbers of neutrons, making $$^{14}C$$ radioactive.

Question 3

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

Accepted Answer

Covalent bonds involve the sharing of electrons between atoms, while ionic bonds involve the transfer of electrons from one atom to another.

Question 4

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}$$ M

Question 5

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

Accepted Answer

Water's high surface tension due to hydrogen bonding

Question 6

Which of the following best explains why changes in pH can be dangerous to living organisms?

Accepted Answer

Changes in pH can alter the structure and function of proteins and enzymes, disrupting cellular processes.

Question 7

Which of the following is a correct statement about the role of buffers in biological systems?

Accepted Answer

Buffers maintain a stable pH by neutralizing excess acids or bases.

Question 8

Which of the following best describes the difference between a hypothesis and a scientific theory?

Accepted Answer

A hypothesis is a tentative explanation that can be tested, while a theory is a well-supported explanation based on a body of evidence.

Question 9

Which of the following molecules is most likely to dissolve in water?

Accepted Answer

A polar molecule with hydrogen bonds

Question 10

Which statement best describes the role of carbon in organic molecules?

Accepted Answer

Carbon can form four covalent bonds, allowing for complex and diverse molecular structures.

Question 11

A molecule has the formula $$C_6H_{12}O_6$. Which type of isomerism could exist between two molecules with this formula?

Accepted Answer

Structural isomerism due to different connectivity of atoms

Question 12

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

Accepted Answer

Ice is less dense than liquid water because hydrogen bonds hold water molecules further apart in the solid state.

Question 13

Which of the following is a consequence of the addition of a phosphate group to a molecule?

Accepted Answer

It increases the molecule's energy and can activate or deactivate its function.

Question 14

Which of the following best describes the difference between hydrogen bonds and Van der Waals interactions?

Accepted Answer

Hydrogen bonds are stronger and occur between polar molecules, while Van der Waals interactions are weaker and occur due to temporary dipoles.

Question 15

Which of the following is a correct statement about acids and bases?

Accepted Answer

Bases have a high pH and release $$OH^-$$ ions in solution.

Question 16

Which of the following best explains the importance of functional groups in organic molecules?

Accepted Answer

Functional groups are responsible for the chemical properties and reactions of organic molecules.

Question 17

A buffer solution is made by mixing a weak acid and its conjugate base. If a small amount of strong acid is added, what will happen to the pH?

Accepted Answer

The pH will decrease slightly, but the buffer will resist large changes.

Question 18

Which of the following best describes the role of water as a solvent in biological systems?

Accepted Answer

Water dissolves many polar and ionic substances, facilitating chemical reactions in cells.

Question 19

Which of the following is a correct statement about the organization of matter in living systems?

Accepted Answer

Atoms combine to form molecules, which then form cells and tissues.

General Biology: Foundational Concepts and Learning Objectives

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