A1.1 Water

Question 1

Why is water referred to as a universal solvent?

Answer 1

Because many things dissolve in it

Question 2

What is the medium in which most life processes occur?

Answer 2

water

Question 3

Cohesion

Answer 3

Molecules of the same kind attracted to each other (in this case water).

Question 4

What sort of bonds are between the H and O atoms in water?

Answer 4

Polar covalent bonds

Question 5

Why do hydrogen bonds form between water molecules?

Answer 5

Because of their polarity, the positive side of the water molecules (Hydrogens) is attracted to the negative side of other water molecules (Oxygen), a hydrogen bond is formed between the two

Question 6

In water the hydrogens have a slight ___ charge and the oxygen has a slight ___ charge. Overall the molecule has ___ charge.

Answer 6

positive, negative, no/neutral

Question 7

What sort of bonds form between water molecules?

Answer 7

Hydrogen

Question 8

Why are water molecules cohesive?

Answer 8

Because of the hydrogen bonds that form between the molecules

Question 9

Why can some animals live/walk on water?

Answer 9

Because the water molecules at the surface are more attracted to each other than they are to the air, the hydrogen bonds (cohesion) allow this.

Question 10

Adhesion

Answer 10

The attraction of water to charged or polar surfaces. It allows water to flow against gravity (capillary action).

Question 11

How does adhesion work?

Answer 11

Hydrogen bonds form between the H on water and a charged/polar surface.

Question 12

Hydrophyllic

Answer 12

Substances that dissolve readily in water (polar molecules and ionic compounds)

Question 13

Hydrophobic

Answer 13

Substances that do not dissolve readily in water (non polar molecules)

Question 14

Aqueous solutions

Answer 14

Solutions where water is the solvent

Question 15

Buoyancy

Answer 15

An upwards force exerted on an object placed in the medium.

Question 16

Viscosity

Answer 16

The resistance of a fluid to an object moving through it.

Question 17

Thermal conductivity

Answer 17

The ability of a substance to transfer heat.

Question 18

Specific heat capacity

Answer 18

How much heat a substance can absorb or release for a given temperature change.

Question 19

Why is water able to be retained on earth

Answer 19

• Temperatures are low enough for it to condense into a liquid state
• Earth is large enough that its gravitational pull keeps water on or near its surface
• shape of the earths orbit

Question 20

How do theories suggest water came to be on earth?

Answer 20

Initially the earth consisted of molten rock and so conditions were too hot for water to be retained, over a long time the earth cooled. It is theorised that then asteroids containing hydrated minerals “seeded” water on earth when they became a part of the earth’s crust

Question 21

What supports the asteroids “seeded” water theory?

Answer 21

There are similar ratios of heavy to typical water in sea water to asteriods.

Question 22

Heavy water

Answer 22

Contains deuterium (Hydrogen atoms containing an extra neutron) rather than normal hydrogen making it heavier than typical water.

Question 23

What must a planet have to support life?

Answer 23

Liquid water

Question 24

Goldilocks/ habitable zone

Answer 24

An area of our solar system relative to our sun that allows water to exist on the planets in it.