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

Accepted Answer

Water's high specific heat is due to the hydrogen bonds between molecules, allowing it to buffer temperature changes and stabilize environments for living organisms.

Question 2

A scientist is studying two isotopes of carbon: $$^{12}C$$ and $$^{14}C. $$Which statement correctly describes how these isotopes differ and how they are used in scientific studies?

Accepted Answer

They have the same number of protons but different numbers of neutrons; $$^{14}C is $$radioactive and used in radiometric dating.

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}$$ \ \mathrm{M}$$

Question 5

Which property of water allows insects, such as water striders, to walk on the surface of a pond?

Accepted Answer

Cohesion due to hydrogen bonding, resulting in surface tension

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 shape and function of proteins and enzymes, disrupting cellular processes.

Question 7

Which of the following statements about carbon is correct and explains its importance in organic molecules?

Accepted Answer

Carbon can form four covalent bonds, allowing for a diversity of stable and complex organic molecules.

Question 8

A molecule has the formula $$C_6H_{12}O_6$. Which class of organic molecules does it most likely belong to, and what is its primary function in cells?

Accepted Answer

It is a carbohydrate, primarily used for immediate energy supply.

Question 9

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

Accepted Answer

Buffers minimize changes in pH by accepting or donating $$H^+$$ ions when acids or bases are added.

Question 10

Which of the following scenarios best illustrates the concept of emergent properties in biology?

Accepted Answer

A collection of heart cells working together can pump blood, a function not possible by individual cells alone.

Question 11

Which of the following best explains why ice floats on liquid water, and why is this important for aquatic life?

Accepted Answer

Ice is less dense than liquid water due to the hydrogen-bonded lattice structure, allowing it to float and insulate aquatic environments.

Question 12

Which of the following is an example of a hypothesis in the scientific method?

Accepted Answer

If plants are given more sunlight, then they will grow taller.

Question 13

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

Accepted Answer

A theory is a well-supported explanation based on evidence, while a hypothesis is a testable prediction.

Question 14

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

Accepted Answer

Functional groups are specific groups of atoms that determine the chemical reactivity and properties of organic molecules.

Question 15

A researcher adds a phosphate group to a molecule of ADP to form ATP. Which type of reaction is this, and why is it important for cells?

Accepted Answer

This is a dehydration synthesis reaction, which stores energy in the newly formed ATP molecule.

Question 16

Which of the following best describes the difference between cohesion and adhesion in water?

Accepted Answer

Cohesion is the attraction between water molecules, while adhesion is the attraction between water molecules and other substances.

Question 17

Which of the following best explains why hydrocarbons are nonpolar and hydrophobic?

Accepted Answer

Hydrocarbons contain only carbon and hydrogen atoms with nonpolar covalent bonds, so they do not interact well with water.

Question 18

A solution has a $$[OH^-]$$ concentration of $$1 	imes 10$$^{-10}$$ \ \mathrm{M}. $$What is the pH of this solution?

Accepted Answer

pH = 4

Question 19

Which of the following is a real-life example of how the addition or removal of a functional group can change the function of a biological molecule?

Accepted Answer

Adding a methyl group to DNA can regulate gene expression.

General Biology: Foundations, Chemistry of Life, and Organic Molecules – Learning Objectives Study Guide

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