WATER INFO

Question 1

What are he four properties of water?

Answer 1

1. Cohesion of water
2. How water moderates temperature
3. ice floating
4. water solvent

Question 2

Define Hydrogen bonds. Give an example of molecule and compounds that are held together.

Answer 2

“Weaker bond, due to electrical attraction”
Hydrogen bonds: form a weak chemical bond when a positive hydrogen atom from one polar molecule that is attracted to a partially negative atom in another molecule
ex: between water molecules; makes water “sticky”

Question 3

What is cohesion of water? Why is it important?

Answer 3

Water molecules stick together due to weak hydrogen bonds that exist between the molecules
It is important because trees (plants) use this force to transport water through the roots to the leaves against the forces of gravity. It is also related to surface tension.

Question 4

How does water moderate temperature? Why is it important?

Answer 4

Water has a high heat capacity -> if resists changing temperature when heat is added because the hydrogen bonds in water need to be broken first before it can be heated.
This is important because after a substance evaporates, the surface left behind cools down, like when humans sweat it cools down their skin; on a global level water moderated earth’s climate.

Question 5

How is water a good solvent? Why is it important?

Answer 5

Due to water’s high polarity, it is a great solvent for other polar compounds because “like dissolves like”
Things that dissolve in water are hydrophilic “water loving” and things that don’t are hydrophobic “water hating”
This is important because water is the solvent in all living organisms/cells so it can transport many substance in the organism; for humans they transport through blood; for trees they transport through sap.

Question 6

How does ice float? Why is it important?

Answer 6

Ice is less dense than liquid water because ice crystals form, it has a hexagonal shape due to the hydrogen bonds; which leaves a lot of empty space which makes it less dense so it floats.
This is important because floating ice insulates the water underneath which means the water below won’t freeze and the living organisms in there will survive.

Question 7

Why is water important for life on earth?

Answer 7

1. It covers nearly 3/4’s of earth’s surface
2. It is the only substance to occur naturally in all three phases (liquid, gas, solid)
3. Cells are mostly made of it