HYDROGEN, OXYGEN, THE ATMOSPHERE, POLLUTION Flashcards

1
Q

what is the word equation for metal + water (steam- for unreactive metals)

A

metal + water -> metal oxide + hydrogen

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2
Q

what is the word equation for metal + water with ( K, Na, Ca )

A

metal + water -> metal hydroxide + hydrogen

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3
Q

describe the observations with potassium + water

A
  • it floats and fizzes
  • moves around on the surface of the water
  • melts into a silver ball
  • it catches fire and burns with a lilac flame
  • it eventually gets smaller and disapears
  • it is a very violent reaction
  • when universal indicator is added, the solution turns blue/black indicating that a string alkali has been produced.
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4
Q

what is the equation (word and chemical) for potassium + water

A

potassium (s) + water (l) -> potassium hydroxide (aq) + hydrogen (g)

K + H2O -> KOH + 1/2H2

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5
Q

is potassium + water a useful method for preparing hydrogen

A

no, because the reaction was too violent and hard to contain

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6
Q

describe the observations for sodium and cold water

A
  • it floats
  • it moves around on the surface of the water
  • it fizzes
  • melts into a silvery ball
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7
Q

what is the word and chemical equation for sodium and water

A

sodium (s) + water (l) -> sodium hydroxide (aq) + hydrogen(g)

2Na + 2H2O -> 2NaOH + H2

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8
Q

is sodium and water a useful method for preparing hydrogen

A

no, the metal is too reactive (not as violent as K)

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9
Q

how can you prepare hydrogen

A

it can be prepared by reacting water or steam with a metal

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10
Q

describe the observations for calcium and cold water

A
  • the calcium sinks and effervesces (bubbles and fizzes)
  • it fizzes and gas bubles are produced and the gas is collected at the top of the test tube.
  • the calcium bobs up and down
  • a white suspension of calcium hydroxide is seen and the water gets warm
  • it is a good way of collecting hydrogen
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11
Q

what is the word and chemical equation for calcium and water

A

calcium (s) + water (l) -> calcium hydroxide(aq) + hydrogen(g)

Ca + 2H2O -> Ca(OH)2 + H2

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12
Q

describe the observations for magnesium and steam

A
  • the magnesium burns with a bright white light
  • a white ash (solid) remains (MgO)
  • a colourless gas is collected
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13
Q

describe the observations for magnesium and cold water

A

the magnesium sinks, it is a very slow reaction and would take a week to collect half a test tube of hydrogen

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14
Q

what is the word and chemical equation for magnesium and water (g)

A

magnesium + water (g) -> magnesium oxide + hydrogen

Mg (s) + H2O(g) -> MgO + H2(g)

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15
Q

describe how aluminium reacts with water

A

aluminium cannot react with hot or cold water

aluminium foil does not react with steam - it has an oxide layer of the surface however, if this layer is removed it will then react

powdered aluminium reacts with steam when heated to red heat

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16
Q

what is the word and chemical equation for aluminium and steam

A

aluminium + steam -> aluminium oxide + hydrogen

2Al(s) + 3H2O(g) -> AlO3 + 3H2(g)

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17
Q

describe how zinc reacts with water

A

zinc cannot react with react with hot or cold water

zinc can react when it’s heated with steam

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18
Q

what is the word and chemical equation for since and steam

A

Zinc(s) + water (g) -> zinc oxide(s) + hydrogen(g)

Zn + H2O -> ZnO + H2

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19
Q

describe the appearance of zinc oxide when it has reacted with steam

A

it is a yellow coal

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20
Q

describe how iron reacts

A

iron rusts slowly in the prescence of air and water

it reacts reversible with steam at red heat

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21
Q

what is the word and chemical equation for iron and steam

A

Iron + water (g) -> iron oxide + hydrogen

3Fe (s) + 4H2O (g) -> FeO4(s) + 4H2(g)

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22
Q

describe the appearance of iron oxide when it has reacted iron with steam

A

it is a black powder

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23
Q

describe how copper reacts with water and steam

A

copper does not- it is below hydrogen in the reactivity series so cannot displace the hydrogen from water

(metal + water is a displacement reaction)

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24
Q

when creating hydrogen with a metal describe what must happen for the reaction to work

A

the reaction is a displacement reaction so the metal must be above hydrogen in the reactivity series for the reaction to work - metal + acid is usually a lot more violent than metal + water

there is also anhydrous copper sulphate which is the catalyst and speeds up the reaction

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25
Q

describe the word equation for metal + acid

A

metal + acid -> salt + hydrogen

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26
Q

describe salts

A

an acid in which the hydrogen has been replaced by a metal

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27
Q

metal + sulfuric acid -> ?

A

metal sulfate + hydrogen

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28
Q

metal + hydrochloric acid -> ?

A

metal chloride + hydrogen

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29
Q

metal + nitric acid -> ?

A

metal nitrate + hydrogen

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30
Q

what is a substance which speeds up a reaction but remains chemically unchanged?

A

a catalyst

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31
Q

what is the word and chemical equation for zinc and sulfuric acid

A

zinc + sulfuric acid -> zinc sulfate + hydrogen

Zn (s) + H2SO4 (aq) -> ZnSO4 (aq) + H2 (g)

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32
Q

describe the observations of potassium and sodium + acid

A

you don’t - it’s too violent

(both potassium and sodium are very reactive more so than hydrogen)
(both potassium chloride and sodium chloride are soluble)

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33
Q

describe what happens with calcium + hydrochloric acid for making hydrogen

A

calcium is more reactive than hydrogen

calcium chloride is soluble

it’s very violent but not a dangerous as K and Na

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34
Q

describe what happens with calcium + sulfuric acid

A

calcium sulfate is insoluble (CaSO4 insoluble)

calcium is more reactive than hydrogen

reaction is very slow (doesn’t really happen at all

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35
Q

describe what happens with copper plus acid to make hydrogen

A

copper is below hydrogen so won’t react (the salt is insoluble)

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36
Q

describe what happens in the experiment with hydrochloric acid and chromium powder

A

the powder sinks to the bottom and starts to react with the hydrochloric acid

it effervesces and goes cloudy to blue and then green

hydrogen is given off after using a lit splint and it popped

(chromium is a grey powder and hydrochloric acid is a colourless solution)

chromium is a transition metal and therefore has different valencies the compounds of chromium with different valencies have different colours - v2 = sky blue , v3 = green , v6 = orange/yellow

37
Q

write the word and chemical equation for chromium and hydrochloric acid

A

Chromium + Hydrochloric acid -> Chromium chloride + Hydrogen

2Cr (s) + 6HCl (aq) -> 2CrCl3 (aq) + 3H2 (g)

38
Q

what is the Mr of air

A

29

39
Q

how do you collect hydrogen

A

(over water as hydrogen is insoluble)

|^^^| (1)down ward displace meant of air as H2 is less dense (Mr 2) 
| | | |
| | | | 
| \ \ |\_\_\_
   -----
40
Q

magnesium + hydrochloric acid

A

magnesium + hydrochloric acid -> magnesium chloride + hydrogen

Mg (s) + 2HCl(aq) -> MgCl2(aq) + H2(g)

41
Q

magnesium + nitric acid

A

magnesium + nitric acid -> magnesium nitrate + hydrogen

42
Q

aluminium + HCl

A

aluminium + hydrochloric acid -> aluminium chloride + hydrogen

2Al + 6HCl -> 2AlCl3 + 3H2

43
Q

aluminium + sulfuric acid

A

-> aluminium sulfate + hydrogen

2Al + H2SO4 -> Al2(SO4)3

44
Q

zinc + hydrochloric acid

A

-> zinc chloride + hydrogen

ZnCl2 + H2

45
Q

zinc + sulfuric acid

A

-> zinc sulfate + hydrogen

ZnSO4 + H2

46
Q

iron + nitric acid

A

-> iron nitrate (brown solution) + hydrogen

Fe(NO3)2 + H2

47
Q

iron + sulfuric acid

A

-> iron sulfate (green solution) + hydrogen

FeSO4 + H2

48
Q

when burning hydrogen in air wha does it make

combustion

A

water

49
Q

in the experiment with burning hydrogen in air- what’s apparatus do you use?

A

woulfe bottle
u-tube
retort

sink and cold surface in the retort

zinc + dilute sulfuric acid
anhydrous calcium chloride

50
Q

in the experiment to show hydrogen produces water when burnt in air - what is the purpose of the cold surface in the retort

A

it’s to condense the water vapour

51
Q

in the experiment to show hydrogen produces water when burnt in air - what is the purpose of the anhydrous calcium chloride

A

it is a drying agent- it dries up any excess water from the hydrogen

52
Q

in the experiment to show hydrogen produces water when burnt in air - how can you show that the liquid collected contains water (chemical test- works with pure or impure water)

A

add water to the anhydrous copper sulfate powder which is white. it should then turn to hydrous copper sulfate and the powder should them turn blue

CuSO4 + 5H2O -> CuSO4 5H2O

53
Q

in the experiment to show hydrogen produces water when burnt in air - how can you show that the liquid collected was pure water

A

boil at 100degrees or freeze at 0degrees

Impure would boil at a much higher temp and would freeze at a lower temperature

54
Q

what is It called when oxygen is removed

A

reduction reaction

55
Q

what is reduction

A

the removal of oxygen

56
Q

explain how hydrogen can remove oxygen from certain metal oxides

A

the removal of oxygen is called reduction so hydrogen is acting as the reducing agent

57
Q

in the experiment where hydrogen removes the oxygen from metal oxides - what apparatus do you need

A

porcelain boat (with lead (II) oxide)
Bunsen
hard glass tube
hydrogen and hydrogen flame

58
Q

explain how hydrogen and lead can switch places in the reactivity series

A

when it is hot enough, Pb and H switch places on the reactivity series

59
Q

what is the word and chemical equation with the hydrogen displacing oxygen in metal oxides experiment

A

hydrogen + lead (II) oxide -> water + lead

H2 + PbO -> H2O + Pb

60
Q

in the experiment where hydrogen removes the oxygen from metal oxides - why don’t you light the hydrogen at the end of the tube until all the air has been swept out of the apparatus?

A

The hydrogen would react with the oxygen in the reminding air and set light to the oxygen resulting in your apparatus burning.

61
Q

in the experiment where hydrogen removes the oxygen from metal oxides - at the end of the experiment, why do we turn off the Bunsen but keep passing hydrogen going over the metal while it cools down?

A

it could turn back to lead oxide if the air gets back into the tube, so while you let it cool, keep the hydrogen going over it so it stays as just lead

62
Q

in the experiment where hydrogen removes the oxygen from metal oxides - you repeat experiment and weigh several times until a constant mass is achieved, what is a constant mass?

A

constant mass is when the mass remains the same (pure lead) after weighing it several times after the experiment.

63
Q

in the experiment where hydrogen removes the oxygen from metal oxides - which metals oxides can hydrogen reduce

A

any metals below hydrogen in the periodic table (plus lead if hot enough)

64
Q

in the experiment where hydrogen removes the oxygen from metal oxides - what are the advantages of using hydrogen rather than a more reactive metal?

A

a metal oxide reaction is violent

you have to separate the two solids, copper and MgO (if you use a more reactive metal e.g. magnesium)

more reactive metals can be explosive

65
Q

complete the word and chemical equation

hydrogen+ copper oxide ->

A

hydrogen+ copper oxide -> water + copper

H2 + CuO -> H2O + Cu

66
Q

complete the following equation

hydrogen + silver (I) oxide ->

A

hydrogen + silver (I) oxide -> water + silver

H2 + Ag2O -> H2O + 2Ag

67
Q

describe the simple test for hydrogen gas

A

use a burning splint and hold it at the mouth of a test tube containing the gas, if hydrogen is present you will hear a squeaky pop.

68
Q

in the simple test for hydrogen - why is it important that the splint is held at the mouth of the tube rather than inside the test tube?

A

there would not be enough oxygen from the air in the test tube for the reaction to take place

69
Q

what are the uses of hydrogen

A
  • manufacture of ammonia by the Haber process
  • hardening of vegetable oils to margarine
  • oxy-hydrogen flame welding and cutting
  • rocket fuel
70
Q

describe the manufacture of ammonia (by the Haber process)

A

(use for hydrogen- NH3) ammonia is used to manufacture fertilisers such a as ammonium sulfate or ammonium nitrate.

1) nitrogen is reacted with hydrogen to make ammonia

in the conditions of:

temp: 450degrees C
pressure: 200atmospheres (200x normal pressure)
catalyst: iron

2) ammonia is then reacted with sulphuric or nitric acid to give ammonium sulfate / nitrate which are used as fertilisers

71
Q

what is the reaction by the hater process where hydrogen is reacted with nitrogen to make ammonia for fertilisers

A

N2(g) + 3H2(g) <=> 2NH3(g)

72
Q

when ammonia is produced from the Haber process to make fertilisers what is it reacted with to make fertilisers

A

sulfuric or nitric acid

73
Q

when ammonia is produced from the Haber process to make fertilisers what are the reactions that take place to make fertilisers

A

2NH3 + H2SO4 -> (NH4)2SO4

NH3 + HNO3 -> NH4NO3

74
Q

what is combustion

A

burning in air

75
Q

how do you identify a salt

A

salts can be easily identified since they usually consist of positive ions from a metal and negative ions from a non- metal

76
Q

what percentage of gases are found in air

A
Nitrogen 78%
Oxygen 21%
Argon 0.96%
Carbon dioxide 0.03% 
Neon 0.0006%
77
Q

describe the chemical test for water

A

add anhydrous copper sulfate (white powder) to water - if water is present then the powder will change to a blue colour

78
Q

Metal + Acid -> ?

A

Salt + Hydrogen

79
Q

Describe the laboratory preparation of oxygen from hydrogen peroxide

A

When dilute hydrogen peroxide is added (H2O2) is decomposed either by heating or by the use of a catalyst such as manganese oxide MnO2, oxygen is evolved and water is left behind

80
Q

the equation to show he decomposition of hydrogen peroxide

A

hydrogen peroxide -> water + oxygen

2H2O2 (aq) -> 2H2O (l) + O2(g)

81
Q

describe a soluble basic (alkaline) oxide

A

these oxides dissolve in water to form hydroxides

they react with acids to form salts but don’t react with other alkalis

group 1 and some group 2 oxides are a type of these oxides

82
Q

describe insoluble basic oxides

A

these oxides do not dissolve in water

they react with acids to form salts

don’t react with other alkalis

these include some group 2 oxides and transition metals

83
Q

describe amphoteric oxides

A

these oxides do not dissolve in water

they react with alkalis to form salts and react with alkalis to form salts with weird names

metals near to the non-metal boarder are of this type e.g zinc or aluminium

84
Q

describe acidic oxides

A

these oxides usually dissolve in water to form acids

react with alkalis to form salts but not with other acids

these are usually non-metals

85
Q

when do salts form

A

when a metal replaces hydrogen in the acid

86
Q

what happens when magnesium burns in oxygen

A

2Mg (s) + O2 -> 2MgO (s)

Magnesium burns with a bright white flame and forms a white ash

87
Q

magnesium oxide + water ->

A

2MgO (s) + H2O (l) -> Mg(OH)2 (aq,s)

magnesium hydroxide is PH10 (alkaline)

88
Q

carbon + oxygen ->

A

C(s) + O2(g) -> CO2(g)

carbon a black solid burns steadily with a yellow flame to form Carbon Dioxide (colourless flame) or sometimes CO