A1.1 Water

Question 1

S-

Answer 1

partial negative

Question 2

electromagnetivity

Answer 2

Strength of attraction (affinity) to electrons

Question 2

Rule for electronegativity

Answer 2

Further to the right of the periodic table, the higher the electronegativity

Question 2

S+

Answer 2

partial positive

Question 3

why in water is oxygen S- and hydrogen is S+

Answer 3

Oxygen is S- while hydrogen is S+ because hydrogen electrons are being pulled to oxygen therefore having a high electronegativity in oxygen.

Question 4

What is a hydrogen bond?

Answer 4

A weak bond between two molecules occurs due to the electrostatic attraction between a proton in one molecule and an electronegative atom in the other

Question 5

What kind of biological structures does water maintain?

Answer 5

Water contributes to the formation of cell membranes
Water impacts folding of proteins
Water surrounds DNA to support the double-helix

Question 6

Why is water a temperature buffer?

Answer 6

Water has a relatively high specific heat capacity and for a liquid a high boiling point of 100 degrees celsius due to its strong covalent bonds between hydrogen and oxygen.

Question 7

Adhesion vs Cohesion

Answer 7

Adhesion - Water is attracted to other substances
Cohesion - water is attracted to water

Question 8

Hydrophobic

Answer 8

hates water

Question 9

hydrophillic

Answer 9

loves water

Question 10

Why can ice float on water?

Answer 10

Ice can float one water due to there being gaps in the lattice of ice causing the density of ice to be lower. This is beneficial for habitats such as Antarctica and marine life as well.

Question 11

How much of earth’s surface is covered by water?

Answer 11

71%

Question 12

When did first DNA/ protein lives develop?

Answer 12

3.6 billion years ago

Question 13

How did water get onto earth

Answer 13

A theory is asteroids a few hundred Km across are the most likely reason for water on earth, specifically the asteroids that dominate the asteroid belt between mars and jupiter.

Question 14

What is deuterium?

Answer 14

Deuterium is an isotope of hydrogen meaning it is the same element but with an EXTRA neutron meaning when bonded with oxygen it is known as heavy water.

Question 15

How is water retained on earth?

Answer 15

Gravity - earth’s gravity keeps water from escaping the planet.

The distance between the sun and the earth - the distance between earth and the sun is large enough so the boiling point of water isn’t reached on earth hence stopping evaporation. The distance is 93 million miles.

Question 16

What is astrobiology?

Answer 16

The study of the origins, distribution and possibility of life in the universe

Question 17

Circumstances necessary for life to exist on a planet

Answer 17

Luck - all the right chemicals at the same time

Time - on earth the evolution of life took billions of years

Location - not too hot or too cold

Question 18

Chemicals necessary for life to exist

Answer 18

Water - functions as a solvent allowing all chemical reactions to take place.

Carbon - simple building block organisms need to form organic compounds such as proteins, carbohydrates and lipids

Nitrogen - need for amino acids

Phosphorous - key component of ATP which provides energy to drive and support many processes in living organisms

Suffer - part of many biochemical processes on earth most enzymes can’t function without it.