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Chemistry > Exam > Flashcards

Exam Flashcards

0
Q

Composition of air now

A

78% nitrogen
21% oxygen
1% argon, water vapour, carbon dioxide
Traces of neon, methane, nitrate oxide

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1
Q

Composition of air in the past

A

Mostly carbon dioxide
Little or no oxygen
Small amounts of water vapour, ammonia and methane
(As Earth cooled down, most of the water vapour condensed and formed oceans)

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2
Q

The early atmosphere was probably formed from the gases given out by

A

Volcanoes

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3
Q

Why did the proportion of oxygen go up

A

Photosynthesis

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4
Q

Why did the proportion of carbon dioxide go down (3)

A
  • it was locked up in sedimentary rocks like limestone and in fossil fuels
  • absorbed by plants for photosynthesis
  • dissolved into oceans
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5
Q

Two ways of producing CO2 (equations)

A
  • calcium carbonate + acid = salt (calcium chloride) + water + CO2
  • metal carbonate + heat = CO2 + metal oxide (thermal decomposition)
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6
Q

How to produce oxygen

A

Hydrogen peroxide + manganese oxide (catalyst) = water + oxygen

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7
Q

How to produce hydrogen

A

Acid + metal = salt + hydrogen

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8
Q
  • carbon + oxygen =
  • sulphur + oxygen =
  • magnesium + oxygen =
A
  • carbon dioxide
  • sulphur dioxide
  • magnesium oxide
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9
Q

When was Earth formed

A

Around 4.5 billion years ago

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10
Q

Carbon dioxide’s solubility and density

A

This colourless, odourless gases denser than air and slightly soluble in water

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11
Q

Two uses of carbon dioxide and why

A
  • fizzy drinks (dissolves in water under pressure - when drink opened, pressure falls and gas bubbles out of solution)
  • fire extinguishers (denser than oxygen so displaces it and none can reach the fire so it is put out)
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12
Q

Metal oxides = (alkaline/acidic)

Non-metal oxides = (alkaline/acidic)

A

=alkaline

=acidic

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13
Q

Burning compounds produces…

A

A mixture of oxides, including CO2 from carbon based fuels

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14
Q

CO2 is what kind of gas

A

A greenhouse gas

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15
Q

The reactions of (?) and (?) with water produce acidic solutions

A

Carbon dioxide and sulphur dioxide

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16
Q

Pollutant gases which contribute to acid rain:

A

sulphur dioxide and nitrogen oxides

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17
Q

Problems caused by acid rain:

A
  • kills plant life
  • pollutes rivers and streams - kills aquatic life
  • respiratory irritant - bad for asthma
  • corrosion - damages buildings
18
Q

Test for oxygen

A

Relights a burning splint

19
Q

Test for carbon dioxide

A

Turns limewater milky

20
Q

Test for hydrogen

A

Makes a squeaky popping noise when glowing splint is put in a test tube of hydrogen

21
Q

Magnesium in air:

A

Metal, turns blue, bright white light

22
Q

Sulphur in air:

A

Non metal, bright blue light, turns to yellow powder, smelly

23
Q

Rate of reaction is affected by:

A

Temperature
Surface area
Concentration
Catalysts

24
Q

For collecting gases by displacement:

A

You put the mixture in a flask with a bung that has a tube coming out of it leading to a tray full of water with an upside down test tube dipped in to collect the gas

25
Q

For thermal decomposition: (method)

A

You have a test tube with the carbonate inside, heated underneath, and there is a bung on the test tube with a tube going into another test tube with limewater inside - wait for the limewater to turn milky

26
Q

Uses of metals

A
  • aluminium~make saucepans(heat conductor)
  • copper~make electrical wires(electrical conductor)
  • gold~jewellery(shiny)
  • lead~add weight when scuba diving(dense)
27
Q

Metal properties

A

Shiny, solid(except mercury), high density, strong, malleable(bend), good heat conductor, good electricity conductor, some magnetic(iron, cobalt, nickel), sonorous

28
Q

Non-metal properties

A

Dull, half solids, half gases, one(bromine) liquid, low density, weak, brittle(hammer), insulators except graphite, not magnetic, dull sound

29
Q

Formula for: ammonium ion

A

NH4

30
Q

Formula for: hydrochloric acid

A

HCl

31
Q

Formula for: sulphate ion

A

SO4

32
Q

Formula for: sulphur

A

S

33
Q

Formula for: carbonate ion

A

CO3

34
Q

Formula for: potassium

A

K

35
Q

Formula for: water

A

H2O

36
Q

Formula for: nitric acid

A

HNO3

37
Q

Formula for: sulphuric acid

A

H2SO4

38
Q

Formula for: hydroxide ion

A

OH

39
Q

Formula for: nitrate ion

A

NO3

40
Q

Formula for: methane gas

A

CH4

41
Q

Formula for: ammonia gas

A

NH3

42
Q

Formula for: sodium

A

Na

43
Q

Some noble gases

A

Helium, neon, argon, xenon

Chemistry (2 decks)

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