Q: Which of the following equations correctly converts 50 calories to joules?

$$50 \times 4.184 = 209.2\ \mathrm{J}$$

Q: If 1 calorie is the amount of heat required to raise the temperature of 1 g of water by 1°C, how much heat is required to raise the temperature of 250 g of water by 2°C?

$$250 \times 2 = 500\ \mathrm{cal}$$

Question 1

Which property of water is primarily responsible for the ability of ice to float on liquid water?

Accepted Answer

Water's expansion upon freezing due to hydrogen bonding

Question 2

A scientist is studying a plant that transports water from its roots to its leaves. Which two properties of water are most directly involved in this process?

Accepted Answer

Cohesion and adhesion

Question 3

Why does water have a high specific heat compared to most other substances?

Accepted Answer

Because hydrogen bonds between water molecules absorb heat when they break and release heat when they form

Question 4

Which of the following best explains why coastal areas tend to have milder climates than inland areas?

Accepted Answer

Water's high specific heat allows it to absorb and release large amounts of heat with little temperature change

Question 5

A solution is made by dissolving 10 g of NaCl in 100 mL of water. In this solution, which term best describes NaCl?

Accepted Answer

Solute

Question 6

Which of the following equations correctly converts 50 calories to joules?

Accepted Answer

$$50 	imes 4.184 = 209.2\ \mathrm{J}$$

Question 7

Which of the following best describes a hydrophobic substance?

Accepted Answer

A substance that does not have an affinity for water because it contains mostly nonpolar bonds

Question 8

During a hot day, a dog pants to cool itself. Which property of water is most directly responsible for this cooling effect?

Accepted Answer

Evaporative cooling due to water's high heat of vaporization

Question 9

Which of the following statements about hydrogen bonds in water is correct?

Accepted Answer

Hydrogen bonds form between the hydrogen atom of one water molecule and the oxygen atom of another water molecule

Question 10

A researcher finds a planet with evidence of liquid water. Why is this significant in the search for extraterrestrial life?

Accepted Answer

Water's unique properties make it an ideal solvent for the chemical reactions necessary for life

Question 11

Which of the following best explains why ice is less dense than liquid water?

Accepted Answer

Hydrogen bonds in ice keep water molecules farther apart in a crystalline lattice

Question 12

If 1 calorie is the amount of heat required to raise the temperature of 1 g of water by 1°C, how much heat is required to raise the temperature of 250 g of water by 2°C?

Accepted Answer

$$250 	imes 2 = 500\ \mathrm{cal}$$

Question 13

Which of the following scenarios best illustrates the concept of adhesion?

Accepted Answer

Water droplets sticking to the surface of a leaf

Question 14

A protein dissolves in water because it contains regions with which of the following characteristics?

Accepted Answer

Ionic and polar

Question 15

Which of the following best describes the process of evaporative cooling?

Accepted Answer

The molecules with the highest kinetic energy leave as gas, lowering the temperature of the remaining liquid

Question 16

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

Accepted Answer

Ice floats on water

Question 17

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

Accepted Answer

Water molecules surround each ion, forming hydration shells due to their polarity

Question 18

A student adds oil to water and observes that the oil does not mix. Which property of oil is responsible for this behavior?

Accepted Answer

Oil is hydrophobic due to its nonpolar bonds

Question 19

Which of the following is the correct definition of a solution?

Accepted Answer

A liquid that is a completely homogeneous mixture of substances

Question 20

Which of the following best describes the relationship between temperature and kinetic energy in water?

Accepted Answer

Temperature represents the average kinetic energy of the molecules in a body of matter

Water and Life: Properties and Biological Importance

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