Front | Back |
What is PVC used for?
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Window frames
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What is Polyethene used for?
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Plastic bags
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What is polytetrafluoroethene(PTFE) used for?
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Non-stick frying pans
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What is meant by a saturated compound?
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This means that the compound has a double bond
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Why do metals have generally high melting and boiling points?
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This is due to the fact that the positive cations are STRONGLY bonded to delocalised electrons
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Do simple molecular substances have generally high or low melting and boiling points?
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They have generally low boiling and melting points
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Why do simple molecular substances have low melting and boiling points?
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This is due to WEAK forces of attraction between molecules
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Why do giant ionic crystals have high melting points and boiling points?
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This is due to STRONG forces of attraction between oppositely charged ions
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Why do giant covalent structures have high melting points?
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They have MANY covalent bonds in ALL DIRECTIONS
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What is a property of polymer gels(such as hydrogels)?
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They have the ability to absorb and expel MUCH water which causes swelling or shrinking due to small changes
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What is the property of Shape memory polymers?
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They have the ability to regian their original shape when heated
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Give two uses of polymer gels.
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Used in nappies
Artificial muscles |
Give one use of shape memory polymers
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Car bodies
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What do photochromic paints do?
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They change colour when exposed to light
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What do thermochromic paints do?
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They change colour when heated
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