water

Question 1

what is cohesion

Answer 1

attraction between molecules of the same type due to polarity of the molecule. Results in surface tension.

Question 2

what is adhesion

Answer 2

attraction between two different substances. water will make hydrogen bonds with other surfaces. eg- transpiration process

Question 3

what is high specific heat

Answer 3

the energy needed to raise 1kg of water by 1degrees. Due to hydrogen bonds, water can absorb or release large amounts of heat energy with little change in actual temperature.

Question 4

what is high latent heat of vaporisation

Answer 4

amount of energy to convert 1kg of a substance from a liquid to a gas.
in order for water to evaporate, hydrogen bonds need to be broken.

Question 5

what is the function of the density of water

Answer 5

1) prevents water from freezing from the bottom up
2) ice forms on the surface first - the freezing of the water releases heat to the water below, creating insulation
3) makes transition between seasons less abrupt

Question 6

is ice less or more dense than as a liquid

Answer 6

ice is less dense as a solid than as a liquid (ice floats)

Question 7

what is the structure of liquid water and frozen water

Answer 7

liquid water = has hydrogen bonds that are costantly being broken and reformed.
frozen water = forms a crystal like lattice whereby molecules are set at fixed distances.

Question 8

why is water a good solvent

Answer 8

as water is polar, the positive and negative parts are attracted to the positive and negative parts of a solute.
the water molecules cluster around the solute molecules and keep them apart. then, they dissolve and a solution is formed.

Question 9

why is water polar

Answer 9

has both positive and negative charges

Question 10

does oxygen act negative or positive

Answer 10

negative

Question 11

does hydrogen act negative or positive

Answer 11

positive

Question 12

how are hydrogen bonds formed

Answer 12

formed between a highly electro-negative atom of a polar molecule and a hydrogen.

Question 13

are hydrogen bonds weak or strong

Answer 13

one hydrogen bond is weak, but many hydrogen bonds are strong.

Question 14

why is water important (6 reasons)

Answer 14

• reactant
• solvent
• transport substances
• high specific heat capacity (temperature control)
• habitat
• ice floats

Question 15

what does water being a solvent mean

Answer 15

molecules can dissolve in water due to the polarity of the water molecule

Question 16

give an example of cohesion

Answer 16

water moves through the xylem in plants