Chapter 3

Question 1

Polarity of the Water Molecule

Answer 1

The water molecule is polar because the electrons spend more time near oxygen than hydrogen, which allows molecules to form hydrogen bonds with eachother

Question 2

What are the five emergent properties of water?

Answer 2

1. Cohesive behavior 2. Adhesive Behavior 3. Ability to moderate temperature 4. Expansion upon freezing 5. Versatility as a solvent

Question 3

What is cohesion?

Answer 3

Hydrogen bonds hold water molecules together, which is cohesion

Question 4

What is adhesion?

Answer 4

The attraction between different substances, for example between water and plant cell walls

Question 5

Moderation of temperature by water

Answer 5

water absorbs heat from warmer air and releases stored heat to cooler air, water can absorb or release a large amount of heat

Question 6

define kinetic energy

Answer 6

kinetic energy is the energy of motion

Question 7

define thermal energy

Answer 7

the kinetic energy associated with random motion of atoms or molecules, it is referred to as heat if it transferred from one body of matter to another

Question 8

what does temperature measure?

Answer 8

temperature is a measure of energy that represents the average kinetic energy of the molecules in a body of matter

Question 9

what is a calorie?

Answer 9

a calorie is the amount of heat required to raise the temperature of 1 gram of water by 1 degree celsius

Question 10

what is specific heat?

Answer 10

the amount of heat that must be absorbed or lost for 1 gram of that substance to change its temperature by 1 degree celsius

Question 11

what is water’s specific heat?

Answer 11

1 cal/ gram/ degrees celsius

Question 12

when is heat absorbed or released in terms of hydrogen bonds?

Answer 12

heat is absorbed when hydrogen bonds break, heat is released when hydrogen bonds form

Question 13

What is evaporative cooling?

Answer 13

As a liquid evaporates, its remaining surface cools, which can help stabilize temperatures in organisms and bodies of water

Question 14

What is a solvent vs a solute?

Answer 14

A solvent is the dissolving agent of a solution and a solute is what is being dissolved

Question 15

How does salt dissolve in water?

Answer 15

When an ionic compound is dissolved in water, each ion is surrounded by a sphere of water molecules called a hydration shell

Question 16

What is a hydrophilic substance?

Answer 16

One that has an affinity for water, loves water

Question 17

What is a hydrophobic substance?

Answer 17

One that does not have an affinity for water, hates water

Question 18

What is Molarity (M)?

Answer 18

the number of moles of solute per liter of solution,

Question 19

What happens when a hydrogen atom in a hydrogen bond between two water molecules shifts from one to the other?

Answer 19

The hydrogen atom that leaves the electron behind is transferred as a proton and becomes a hydrogen ion (H+). The molecule that lose the proton is now a hydroxide ion (OH-). The molecule with the extra proton is now a hydronium ion (H3O+)

Question 20

What is used to describe whether a solution is acidic or basic?

Answer 20

the pH scale

Question 21

how are concentrations of H+ and OH- in pure water?

Answer 21

the concentrations are equal

Question 22

what is an acid?

Answer 22

an acid is any substance that increases the H+ concentration of a solution

Question 23

what is a base?

Answer 23

a base is any substance that reduces the H+ concentration of a solution

Question 24

Acidic solutions vs Basic on pH scale

Answer 24

Acidic solutions are less than 7, and basic solutions are greater than 7