Why is water a liquid at room temperature when other similarly sized but less polar molecules are a gas?
Because the hydrogen bonds between water molecules make it harder for them to escape and become a gas.
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Even with the hydrogen bonds, water has quite a low viscosity. What does this mean?
It can flow easily.
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What are the advantages of water being a liquid at room temperature?
It provides habitats (lakes, seas and rivers); it forms a major component of tissues in living organisms; it provides a reaction medium for chemical reactions; it provides a transport medium (in blood and vascular tissue).
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If water were less dense would living things find it easier or harder to float?
Harder.
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Most liquids get more dense the colder they get. This is true for water only to a certain point. What happens to water as it goes from 4 °C to freezing point?
Because of their polar nature, water molecules align themselves in a structure which is less dense than liquid water. This means that ice is less dense than water and floats.
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What are the advantages of ice being less dense than water?
When the top layer of ponds or lakes freezes, the ice doesn't sink, instead it floats and insulates the water body, making it a more stable environment to live in.
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Why is water such a good solvent?
Because it is polar, the positive and negative parts of the water molecule are attracted to the negative and positive parts of the solute. The water molecules cluster around the charged parts and keep them separated, dissolving the solute.
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What are the advantages of water being such a good solvent?
Molecules and ions can move around and react together in water (e.g. in the cytoplasm which is 70% water). Also molecules and ions can be transported around living things while dissolved in water.
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What is cohesion?
The attraction between water molecules that is caused by hydrogen bonds.
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What are the advantages of water demonstrating cohesion and surface tension?
It allows water to be transported in columns up xylem tissue in plants. It also means insects such as pond-skaters can walk on water.
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Water has a high specific heat capacity. What does this mean? Why is this?
Specific heat capacity is the amount of energy required to increase the temperature of 1 kg of water by 1 °C. It is high in water which means a lot of energy is required because the water molecules are held tightly together by hydrogen bonds.
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What are the advantages of water having a high specific heat capacity?
It creates a stable environment in which aquatic organisms can live. It also creates the stable environment temperature-wise that is necessary for enzyme controlled reactions to happen properly.
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Water also has a high latent heat of vaporisation. What does this mean? Why is this?
It is the energy required to help the molecules break away from each other and become a gas. It is high because the water molecules are held together by hydrogen bonds and so lots of energy is required for their evaporation.
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What are the advantages of water having a high latent heat of vaporisation?
Water can help cool living things and keep there temperature stable.
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Water is also a r_______ in many important biological process such as photosynthesis and hydrolysis reactions for digestion and synthesis of large biological molecules.
REACTANT
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Other cards in this set
Card 2
Front
Even with the hydrogen bonds, water has quite a low viscosity. What does this mean?
Back
It can flow easily.
Card 3
Front
What are the advantages of water being a liquid at room temperature?
Back
Card 4
Front
If water were less dense would living things find it easier or harder to float?
Back
Card 5
Front
Most liquids get more dense the colder they get. This is true for water only to a certain point. What happens to water as it goes from 4 °C to freezing point?
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