A1.1 Water Flashcards
Mrs Chippindall
S-
partial negative
electromagnetivity
Strength of attraction (affinity) to electrons
Rule for electronegativity
Further to the right of the periodic table, the higher the electronegativity
S+
partial positive
why in water is oxygen S- and hydrogen is S+
Oxygen is S- while hydrogen is S+ because hydrogen electrons are being pulled to oxygen therefore having a high electronegativity in oxygen.
What is a hydrogen bond?
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
What kind of biological structures does water maintain?
Water contributes to the formation of cell membranes
Water impacts folding of proteins
Water surrounds DNA to support the double-helix
Why is water a temperature buffer?
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.
Adhesion vs Cohesion
Adhesion - Water is attracted to other substances
Cohesion - water is attracted to water
Hydrophobic
hates water
hydrophillic
loves water
Why can ice float on water?
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.
How much of earth’s surface is covered by water?
71%
When did first DNA/ protein lives develop?
3.6 billion years ago
How did water get onto earth
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.
What is deuterium?
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.
How is water retained on earth?
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.
What is astrobiology?
The study of the origins, distribution and possibility of life in the universe
Circumstances necessary for life to exist on a planet
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
Chemicals necessary for life to exist
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
Sulfer - part of many biochemical processes on earth most enzymes can’t function without it.
