Test 2 Hydrogen Bonds

Question 1

Describe the chemical structure of a water molecule (the atoms that make up a water molecule – think of the formula for water!)

Answer 1

Two Hydrogen (+) connect to one oxygen (-) (polar)

Question 2

Explain what is meant when we say water is “polar”

Answer 2

a water molecule has two poles - a positive charge on the hydrogen pole (side) and a negative charge on the oxygen pole (side)

Question 3

Define hydrogen bond.

Answer 3

The attraction between a partially positive hydrogen molecule and another atom with a partial negative charge

Question 4

List the five properties of water discussed in class

Answer 4

Cohesion, adhesion, high heat capacity, density of ice, and solubility of water

Question 5

Explain how hydrogen bonds relate to the property of cohesion

Answer 5

Attraction of water molecules to each other because of hydrogen bonding

Question 6

Describe how cohesion relates to surface tension.

Answer 6

Water molecules at surface hold on strong because of the polar attraction

Question 7

Describe at least one example of how surface tensions allow water striders/small insects to survive.

Answer 7

It allows them to escape from predators or get to food easier by being able to traverse water

Question 8

Explain how hydrogen bonds relate to the property of adhesion

Answer 8

Water sticks to other polar molecules because of hydrogen bonding

Question 9

Explain why water does not “stick” to non-polar materials.

Answer 9

the attraction of polar molecules due to charges; so no attraction means no stick

Question 10

how cohesion and adhesion work together in capillary action.

Answer 10

Adhesion allows water to climb the sides of plants while cohesion ‘pulls’ up the rest of the water

Question 11

Describe how capillary action allows organisms to survive.

Answer 11

If there was no capillary action plants would not be able to receive water from branches and other parts that are not the roots

Question 12

Explain why water has a high capacity, including how this relates to hydrogen bonds

Answer 12

Because of these bonding/attraction to make water hot, it takes a lot of energy to break those bonds.

Question 13

Explain how water’s high heat capacity relates to the survival of living things

Answer 13

The ocean is home to millions of organisms and if not for this trait ecosystems would be destroyed due to hot waters

Question 14

Describe how the number of hydrogen bonds differs in solid water (ice) versus liquid water

Answer 14

All possible bonds are bonded for water to be in solid form

Question 15

Explain why water is less dense as a solid than as a liquid

Answer 15

Solid hydrogen bonds take up more space than liquid water meaning it is less dense

Question 16

Describe how ice floating contributes to the survival of organisms

Answer 16

Many organisms at the poles rely on the density of ice for habitat and survival (ex: penguins, polar bears)

Question 17

Explain how water’s polar nature allows it to dissolve substances, including where the formation of hydrogen bonds occur

Answer 17

Water can dissolve other polar substances due to their charges. Water performs hydrogen bonds with the substance apart giving the appearance of disappearing

Question 18

Describe why water cannot dissolve materials like oil.

Answer 18

Oil is a non-polar molecule not allowing water to dissolve it by creating hydrogen bonds

Question 19

Describe how washing your hands with soap kills viruses.

Answer 19

Soap is a two-sided molecule that is attracted to fat and water. One side breaks apart the fat wall due to an attraction while the water washes it away.

Question 20

Describe how water acting as a solvent allows organisms to survive

Answer 20

Blood allows humans to survive by transporting the solvent materials (salts, proteins, and carbs) to the necessary cells

Question 21

Explain how a solution can become “saturated” with a solute. Describe what is happening at the molecular level.

Answer 21

Water “solutes” substances by breaking down molecules with it’s polar molecules. When it runs out of molecules to break down with the water is polluted (cloudy)

Question 22

1 example Cohesion

Answer 22

Water bubbles on my arm after I sneeze

Question 23

1 example Adhesion

Answer 23

Dew on grass

Question 24

1 example High heat capacity

Answer 24

Heating soup in a microwave

Question 25

1 example Density

Answer 25

Ice in drink

Question 26

1 example solubility of water

Answer 26

Solubility of water

Question 27

blood

Answer 27

This material contains water with dissolved solutes, like salt, proteins, and carbs; this material then moves around the body, “delivering” those molecules to necessary cells

Question 27

blood

Answer 27

This material contains water with dissolved solutes, like salt, proteins, and carbs; this material then moves around the body, “delivering” those molecules to necessary cells