Introduction Flashcards

1
Q

what are good observations to make when describing substances in practical work?

A
  • solid, liquid, gas?
  • coloured or colourless?
  • crystalline or powdered? (for solids)
  • clear or cloudy? (for liquids)
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2
Q

good observations to make when describing changes during practical work?

A
  • is there any fizzing?
  • has a solid appeared or disappeared?
  • has anything changed colour?
  • are there any unusual sounds or smells?
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3
Q

how to tell if something is a physical change?

A
  • creates no new substances
  • are usually easy to reverse
  • absorb or release small amounts of energy
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4
Q

how to tell if something is a chemical change?

A
  • creates new substances
  • are usually difficult to reverse
  • absorb or release large amounts of energy
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5
Q

what is a chemical test for water?

A

anhydrous copper(II) sulphate turns from white to blue (this tells you that water is present but NOT how pure it is)

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6
Q

what are two physical tests for water?

A
  • melting point = 0 degrees celcius
  • boiling point - 100 degrees celcius
    (purer water matches these properties more closely)
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