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Core 1
w w w . X t r e m
e P a p e r s . c
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Core 1
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Core 2
(a
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Core 3Alternative to practical 1
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Extension 1
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Extension 1 (con'd)
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Extension 2
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Extension 3
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Air and Water page 1
Core 1
a any two usese.g. washing, drinking, sanitation, growing plants etc
b 100o
C
c test add anhydrous / white copper sulphate or anhydrous / blue cobalt chlorideresult copper sulphate goes blue / cobalt chloride goes pink
d(i) test add (sodium / potassium / other suitable) hydroxide or add ammoniaresult brown / red-brown precipitate
(ii) nitrogen, oxygen
e(i) to kill bacteria / germs / to disinfect the water
(ii) lime is alkaline
to neutralise the acid / chlorine / to increase the pH
f impure water contains some solidssolids trapped on stones / sandwater drains through
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Air and Water page 2
Core 2
(i) inert / unreactive
(ii) helium / neon / krypton / xenon / a noble gas
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Air and Water page 3
Alternat ive to Practical 1
a rusty / brown
b level of water level rises / goes up tube
explanation oxygen used up / 1/5 of way up tube / 20% oxygen
c result would go out / popsexplanation oxygen absent / hydrogen present
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Air and Water page 4
Extension 1
Any three fromacid rainsulphur dioxide
burning of fossil fuels containing sulphur sulphuric acid
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Air and Water page 5
Extension 2
i argon filling electric bulbshelium in balloons (not hot air balloons)neon in lights
inert atmosphere for welding
ii any three of these
krypton has complete energy level or has 8edoes not form bondsdoes not need to lose or gain electrons
nitrogen has incomplete energy levelhas five electrons in outer levelneeds to share to complete 8eneeds 3e moreforms a bond
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Air and Water page 6
Extension 3
i from oxygen and nitrogen (in air )high temperature in engine
ii to form carbon dioxideand nitrogen