4991756
Description
Flashcards by Bee Brittain, updated more than 1 year ago
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Created by Bee Brittain
over 8 years ago
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| Question | Answer |
| Water is know as a dipolar molecule, explain why. | Water is described as dipolar, as in a molecule of water, the hydrogen's have a slightly positive charge, where as the oxygen has a slightly negative charge. This means that a molecule of water has two opposite poles (positive and negative), making it dipolar. |
| Water is an important part in metabolic reactions, this means it is a what? | Important Metabolite |
| In a __________ reaction, a molecule of water is ________. However in a __________ reaction, a molecule of water is added in order to _______ a bond. | In a condensation reaction, a molecule of water is formed. However in a hydrolysis reaction, a molecule of water is added in order to break a bond. |
| Water is known as a universal solvent as many things can dissolve in it. Give four things that can dissolve in water. | 1) Inorganic Ions and small hydrophillic molecules such as amino acids, monosaccharides and ATP 2) Enzymes whose reactions take place in solution 3) wastes such as NH3 4) Gases such as O2 and CO2 |
| Water molecules have a property which means they tend to stick together, what is this property and why do they have it? | This property is Cohesion (attraction between molecules of the same type) and they tend to stick together and be cohesive because water is a polar molecule |
| Strong cohesion helps water flow, give an example where this is a very useful property in a living organism | It is how it travels in columns up the xylem in plants |
| When sweat forms, it forms in beads or droplets, why? | The strong cohesion between water molecules means water has high surface tension when it comes into contact with air. This is why beads of sweat are formed, and why insects such as pond skaters can 'walk' across a ponds surface |
| Describe how hydrogen bonds form between water molecules. | Water molecules are polar and because opposite charges attract the positive pole of one H2O molecule is attracted to the negative pole of another H2O molecule = hydrogen bond |
| Hydrogen bonds are very weak, yet in water provide lots of strength. Why? | Although they are very weak when alone, hydrogen bonds can be very strong when there are lots of them |
| Is the latent heat of vapourisation of water high or low? Explain your answer. | The latent heat of vapourisation of water is high due to its hydrogen bonds which require lots of energy to break. So in other words, it takes a lot of (heat) energy to evaporate water. This provides an effective means of cooling through sweat as body heat is used to evaporate the water. |
| Water has a high specific heat capacity, as it takes a lot of energy to heat it up. Why is this? | Water takes a lot of energy to heat it up as the hydrogen bonds between the water molecules can absorb a lot of energy. |
| Give two reasons/instances why the high specific heat capacity of water may be useful to organisms. | 1) Because water can't undergo rapid temperature changes, it means that an aqueous environment would have a very stable temperature. 2) It also means water inside organisms is also fairly stable as it cannot rapidly change temperature, this helps organisms maintain a constant internal body temperature |
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