Question 1

Which property of water allows insects such as water striders to walk on its surface without sinking?

Accepted Answer

Surface tension

Question 2

Why does ice float on liquid water, and why is this important for aquatic life in lakes during winter?

Accepted Answer

Ice is less dense than liquid water, so it floats and insulates the water below.

Question 3

A solution is made by dissolving 56 g of NaCl in 1 liter of water. What is the molarity (M) of this solution? (NaCl molecular weight = 56 g/mol)

Accepted Answer

$$1\ M$$

Question 4

Which of the following best explains why water has a high specific heat?

Accepted Answer

Most of the energy is used to break hydrogen bonds rather than increase the speed of the molecules.

Question 5

What is the main reason water is considered a 'universal solvent'?

Accepted Answer

It has partial positive and negative charges, allowing it to dissolve most polar substances.

Question 6

Which of the following scenarios demonstrates evaporative cooling in humans?

Accepted Answer

Sweating during exercise, where water evaporates from the skin and lowers body temperature.

Question 7

If you have 168 g of NaCl dissolved in 6 liters of water, what is the molarity of the solution? (NaCl molecular weight = 56 g/mol)

Accepted Answer

$$0.5\ M$$

Question 8

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

Accepted Answer

Cohesion is water's attraction to itself; adhesion is water's attraction to other substances.

Question 9

Which of the following is NOT a consequence of water's high specific heat for the environment?

Accepted Answer

Deserts have stable temperatures throughout the day.

Question 10

A student wants to make a 2 Molar (2 M) solution of NaCl in 1 liter of water. How many grams of NaCl should they add? (NaCl molecular weight = 56 g/mol)

Accepted Answer

$$112\ g$$

Question 11

Why is water able to dissolve table salt (NaCl) but not vegetable oil?

Accepted Answer

Water is polar and dissolves polar substances like NaCl, but not nonpolar substances like oil.

Question 12

Which of the following best explains why sweating cools the body?

Accepted Answer

Evaporation of sweat removes molecules with the highest kinetic energy, lowering the average temperature of the skin.

Question 13

Which of the following is a direct result of hydrogen bonding between water molecules?

Accepted Answer

Water has a high surface tension.

Question 14

If you have 28 g of NaCl and want to make a 1 Molar (1 M) solution, how much water should you add? (NaCl molecular weight = 56 g/mol)

Accepted Answer

$$0.5\ liters$$

Question 15

Which of the following statements about heat and temperature is correct?

Accepted Answer

Heat is the total kinetic energy of molecules; temperature is the average kinetic energy.

Question 16

What would happen to aquatic life if ice were denser than liquid water?

Accepted Answer

Ice would sink, causing bodies of water to freeze from the bottom up and threatening aquatic life.

Question 17

Which of the following best describes the molecular structure of water?

Accepted Answer

Water is a polar molecule with oxygen having a partial negative charge and hydrogens having partial positive charges.

Question 18

Which property of water is most responsible for the transport of nutrients and waste in the human body?

Accepted Answer

Versatility as a solvent

Question 19

A student wants to prepare 0.5 moles of MgCl$$_2 ($$molecular weight = 92 g/mol) in solution. How many grams of MgCl$$_2$$ should they weigh out?

Accepted Answer

$$46\ g$$

Question 20

Which of the following is NOT a function of water in the human body?

Accepted Answer

Provides energy for cellular respiration

Chapter 3 Water lecture slides/notes

Study Guide - Practice Questions

Study Guide - Flashcards