Question 1

Which type of chemical bond is formed when the difference in electronegativity between two atoms is greater than 2.0?

Accepted Answer

Ionic bond

Question 2

Water has a high specific heat. Which property of water molecules is primarily responsible for this?

Accepted Answer

Hydrogen bonds between water molecules

Question 3

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

Accepted Answer

Hydrogen bonds in ice create a lattice that is less dense than liquid water

Question 4

A solution has a hydrogen ion concentration $$[H^+] = 1 	imes 10$$^{-4}$$ M. What is the pH of this solution?

Accepted Answer

$$4$$

Question 5

Which functional group is characterized by a carbon atom double-bonded to an oxygen atom?

Accepted Answer

Carbonyl group

Question 6

Which of the following molecules would be considered hydrophobic?

Accepted Answer

Hexane

Question 7

If the pH of a solution changes from 7 to 5, how does the hydrogen ion concentration change?

Accepted Answer

It increases by 100 times

Question 8

Which property of water allows it to move upward through the stem of a plant against gravity?

Accepted Answer

Cohesion and adhesion due to hydrogen bonding

Question 9

Which of the following best describes a buffer in biological systems?

Accepted Answer

A substance that maintains a stable pH by absorbing excess H$$^+ or OH$^-$$ ions

Question 10

Which of the following is true about carbon's ability to form diverse organic molecules?

Accepted Answer

Carbon has four valence electrons, allowing it to form up to four covalent bonds

Question 11

A molecule with the formula $$C_6H_{12}O_6$ can exist as different isomers. What does this mean?

Accepted Answer

The molecules have the same chemical formula but different structures

Question 12

Which of the following best describes a polar covalent bond?

Accepted Answer

Electrons are shared unequally, resulting in partial charges

Question 13

What happens to the pH of water when ammonia ($$NH_3) is $$added?

Accepted Answer

The pH increases and the solution becomes more basic

Question 14

Which of the following functional groups acts as a base by accepting H$$^+$$ ions?

Accepted Answer

Amino group

Question 15

Which property of water is most important for maintaining stable temperatures in living organisms?

Accepted Answer

High specific heat

Question 16

Which of the following statements about hydrogen bonds is correct?

Accepted Answer

Hydrogen bonds are weak individually but have significant effects when many are present

Question 17

A solution has a pH of 3. Which of the following best describes its hydrogen ion concentration compared to pure water?

Accepted Answer

It is 1,000 times higher than pure water

Question 18

Which of the following best explains why salt (NaCl) dissolves readily in water?

Accepted Answer

Water is polar and stabilizes the ions formed from NaCl dissociation

Question 19

Which of the following is a consequence of changes in pH for living organisms?

Accepted Answer

Alteration of protein shape and function

Question 20

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

Accepted Answer

They determine the solubility and chemical reactivity of the molecule

Chemical Bonds and Electronegativity in Biology

Study Guide - Practice Questions