$$1 \times 10$$^{-7}$$\ \mathrm{M}$$

Question 1

Which of the following best explains why water has a high specific heat capacity compared to most other substances?

Accepted Answer

Hydrogen bonds between water molecules absorb heat when they break and release heat when they form, buffering temperature changes.

Question 2

A solution has a hydrogen ion concentration of $$[H^+] = 1 	imes 10$$^{-5}$$\ \mathrm{M}. $$What is the pH of this solution?

Accepted Answer

$$pH = 5$$

Question 3

Which property of water is most directly responsible for the ability of some insects to walk on water?

Accepted Answer

High surface tension due to cohesion between water molecules

Question 4

Which of the following best describes a polar covalent bond?

Accepted Answer

Electrons are shared unequally between two atoms, resulting in partial charges.

Question 5

Why does ice float on liquid water?

Accepted Answer

Hydrogen bonds in ice create a lattice that spaces molecules farther apart, making ice less dense than liquid water.

Question 6

Which of the following statements about electronegativity is correct?

Accepted Answer

Electronegativity is the ability of an atom to attract electrons in a covalent bond.

Question 7

A molecule of methane ($$CH_4) is $$best described as having which type of bonds?

Accepted Answer

Four nonpolar covalent bonds

Question 8

If a solution has a pH of 3, how many times more acidic is it than a solution with a pH of 6?

Accepted Answer

1000 times

Question 9

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

Accepted Answer

Water's polarity allows it to dissolve many ionic and polar substances by surrounding them with hydration shells.

Question 10

Which of the following scenarios would most likely occur if ice were denser than liquid water?

Accepted Answer

Bodies of water would freeze from the bottom up, threatening aquatic ecosystems.

Question 11

A biologist is studying a molecule that does not dissolve in water and forms aggregates when mixed with it. Which term best describes this molecule?

Accepted Answer

Hydrophobic

Question 12

Which of the following equations correctly represents the relationship between pH and hydrogen ion concentration?

Accepted Answer

$$pH = -\log [H^+]$$

Question 13

Which emergent property of water is most important for the transport of water from the roots to the leaves in plants?

Accepted Answer

Cohesion and adhesion

Question 14

A solution at 25°C has $$[H^+] = 1 	imes 10$$^{-7}$$\ \mathrm{M}. $$What is the $$[OH^-] in $$this solution?

Accepted Answer

$$1 	imes 10$$^{-7}$$\ \mathrm{M}$$

Question 15

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

Accepted Answer

Ionic bonds involve the transfer of electrons from one atom to another, while covalent bonds involve the sharing of electrons.

Question 16

Which of the following is a consequence of water's high specific heat for living organisms?

Accepted Answer

Water buffers organisms and environments against drastic temperature changes.

Question 17

A patient is found to have blood with a pH of 7.1. Which of the following best describes the condition of the blood?

Accepted Answer

The blood is slightly acidic.

Question 18

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

Accepted Answer

The partial charges on water molecules surround and separate the Na+ and Cl- ions.

Question 19

Which of the following is NOT an emergent property of water that contributes to Earth's suitability for life?

Accepted Answer

Low heat of vaporization

Question 20

A scientist adds a substance to water and observes that it increases the concentration of $$H^+$$ ions. How should this substance be classified?

Accepted Answer

As an acid

Chemical Bonds and the Properties of Water in Biology

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