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4 Cards in this Set
- Front
- Back
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What is Water? |
Water is a colourless, odorless and tasteless liquid that comprises of 2 hydrogen and 1 oxygen atom It is the most abundant compound on Earth (Approximately 70%) All living things are made up of water (Cells-90% Human Body-65%) |
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Properties of Water |
It is colourless, odorless, shapeless and tasteless It exists in 3 states - solid, liquid and gas It is an excellent solvent ( This is the liquid in which a substance dissolves) Gases can be dissolved in water It has a density of 1 gram per cubic centimetre ( 1g/cm) It has a boiling point of 100°C and freezing point of 0°C (neutral) Water has a pH of 7 (neutral)( pH: measure of how acidic or basic a solution is. ) (neutral)( pH: measure of how acidic or basic a solution is. ) ( pH: measure of how acidic or basic a solution is. ) |
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Properties of Water |
Water is less dense as a solid (ice floats on water) Water has a high specific heat capacity (requires a large amount of heat to raise the temperature of water) Water shows capillary action (water is able to move up a narrow tube) Two properties involved: Adhesion - water molecules sticking to the sides of the tube Cohesion - water molecules stick together They both work together to help the water move up Adhesion + Cohesion = Meniscus Water shows surface tension (attraction between water molecules produce a surface film that allows small objects to remain on the surface of the water e.g- spiders and mosquitoes) |
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Importance of water to living things |
To plants: Seeds need water to bear fruit and germinate Water is needed in photosynthesis Water activates enzymes Water carries minerals throughout the plant Food is carried around the plant in liquid form When soft stemmed plants take in adequate water they remain upright Transpiration from the leaves help to cool down the plant To humans: |
