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Paper 2 Flashcards

(101 cards)

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1
Q

How do you find the empirical formula from the mass of each element combined in a compound?

A

Write out each symbol in a seperate column
Underneath each write mass
Divide the mass by the Ar
Divide that by the smallest answer to get ratio
Write out formula

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1
Q

How do you find the mass of reactants/products?

A

Underline the substance you have been given mass of and the one you’re trying to find. Write the masses above them
Find the Mr for each
Divide Mr of chemical ? by the Mr of the known chemical
Multiply that by the known mass

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2
Q

How do you find the limiting reactant?

A

Work out the number of moles of the first recatant
Look at the ratio and see how much moles of the second reactant there should be
Calculate the number of moles of the second reactant
Compare

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3
Q

What is Avogadro’s Constant?

A

6.02 * 10²³

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4
Q

What are the properties of alkali metals? (6)

A

Malleable
Low melting points
Conduct electricity
Soft and easy to cut
Shiny when freshly cut
Very reactive with non metals

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5
Q

What is the equation for potassium reacting with air?

A

4K (s) + O₂ (g) –> 2K₂O (s)

(Same for any other element, just change the K for whatever else)

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6
Q

What is the equation for lithium reacting with water?

A

2Li (s) + 2H₂O (l) –> 2LiOH (aq) + H₂ (g)

(Same for any other element, just change the Li for whatever else.

Also, the aqueous thing splits into ions e.g.

2LiOH (aq) ===== 2Li+ + 2OH-

)

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7
Q

What are the properties of halogens?

A

Toxic
Corrosive
Non-metals
Poor conductors of heat and electricity
Diatomic

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8
Q

What does chlorine look like at room temperature?

A

Green gas

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9
Q

What does bromine look like at room temperature?

A

Brown liquid

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10
Q

What does iodine look like at room temperature?

A

Purple/black solid

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11
Q

As you go down the group, what happens to halogens?

A

Melting + boiling points increase
Density increases

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12
Q

What are the uses of halogens?

A

Disinfectants and bleaches

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13
Q

What is the use of sodium chloride?

A

Table salt

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14
Q

What is the use of sodium fluoride?

A

Toothpaste

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15
Q

How does the reactivity change as you go down the alkali metals?

A

Goes up

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16
Q

What are the properties of noble gases?

A

Inert
All exist as single atoms
Colourless
Low melting and boiling points
Poor conductors of heat and electricity

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17
Q

How do you calculate the average rate of reaction?

A

Volume of gas / time taken

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18
Q

What is activation energy?

A

Minimum energy for a successful collision

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19
Q

How do catalysts work?

A

Lower the activation energy

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20
Q

What can catalysts help with?

A

Existing bonds to break
Molecules to collide in such a way that they can react and form bonds

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21
Q

How can catalysts be used?

A

Catalytic converters
Enzyme

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22
Q

How do catalytic converters work?

A

Platinum or palladium is used in cars to speed up the reaction of harmful gases (e.g. carbon monoxide) into harmless gases (e.g. nitrogen)

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23
Q

What happens to potassium when it reacts with water?

A

Burns with a lilac flame

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24
What happens to sodium when it reacts with water?
Effervesces rapidly and releases enough energy to melt itself. It then floats on the surface of the water
25
What happens to lithium when it reacts with water?
Fizzes steadily and gets smaller until it disappears
26
What are some examples of endothermic reactions?
Photosynthesis Cracking Thermal decomposition Nuclear fusion
27
What are some examples of exothermic reactions?
Neutralisation Displacement Combustion Nuclear fission
28
What is bond energy?
Energy needed to break one mole of a particular covalent bond
29
What is bond energy measured in?
Kj/mol
30
How is crude oil formed?
From ancient remains of microscopic animals and plants that lived in the sea
31
What is a hydrocarbon?
Molecule made of hydrogen and carbon only
32
What are the layers of fractional distillation of crude oil?
Gases Petrol Kerosene Diesel Fuel oil Bitumen
33
What are gases used for (in terms of crude oil)?
LPG
34
What is petrol used for?
Fuelling cars
35
What is kerosene used for?
Fuelling planes
36
What is diesel used for?
Fuelling cars/lorries
37
What is fuel oil used for?
Fuelling trains
38
What is bitumen used for?
Paving roads
39
What is the general formula of alkanes?
CₙH₂ₙ₊₂
40
What is the general formula of alkenes?
CₙH₂ₙ
41
What are molecules called that have the same molecular formula but different arrangements?
Isomers
42
What is used to test alkanes and alkenes?
Bromine water
43
What colour does bromine water turn in an alkane?
Stays orange/brown
44
What colour does bromine water turn in an alkene?
Orange/brown to colourless
45
What is the equation for complete combustion of hydrocarbons?
Hydrocarbon + oxygen -> carbon dioxide + water
46
What is the equation for incomplete combustion of hydrocarbons?
Hydrocarbon + oxygen -> carbon + carbon monoxide + water
47
What are the 2 tests for water?
White anhydrous copper sulphate turns blue Cobalt chloride paper goes pink -> blue
48
What is acid rain?
Rain with pH lower than 5.2 due to sulphur dioxide
49
How is acid rain formed?
Sulphur dioxide dissolves in water in clouds to form sulphurous acid Some of the sulphurous acid is oxidised to form sulfuric acid
50
What is cracking?
Breaking down long-chain, low demand molecules into short-chain, high demand molecules
51
What are the conditions of cracking?
650c Aluminium oxide catalyst
52
What does cracking form?
An alkane and an alkene
53
How did the atmosphere evolve?
Earth began to cool forming crust and lots of volcanoes About 4 billion years ago, the Earth cooled down and the water vapour in the air condensed, forming oceans which trapped carbon dioxide Carbon dioxide levels fall even more once first plants grow and photosynthesise
54
What evidence is there that there was no oxygen in the early atmosphere?
Volcanoes do not produce oxygen Presence of iron pyrite which only forms when there is no oxygen present
55
What are stromatolites?
Some of the earliest photosynthetic organisms forming sticky mucus which trapped sand and other sediments
56
What are the commonly used plants used to make alcohols?
Beer - barley seeds Wine - grapes Whiskey - barley seeds Vodka - wheat seeds
57
What is the process of fermentation?
Seeds are germinated so that enzymes break down starch into glucose Sugar is dissolved in water and mixed with yeast to form ethanol and carbon dioxide
58
What conditions are needed for fermentation?
Temperature between 20c and 40c Neutral pH Airlock
59
What are the properties of alcohols?
Can be oxidised to make carboxylic acids React with reactive metals and give hydrogen as a product
60
What are some uses of alcohols?
Solvents in cosmetics, medicine, varnishes Fuels (e.g. methanol, ethanol)
61
What is the process of obtaining ethanol throught hydration and what are the conditions?
Ethene mixed with steam and passed over a catalyst of silicon dioxide coated with phosphoric acid 300c temperature 60-70 atmoshperes of pressure
62
How are carboxylic acids made?
Via oxidising alcohols
63
What are the properties of carboxylic acids?
Form solutions of weak acids React with metals to form salt + hydrogen React with bases to form salt + water React with carbonates to form salt, water and carbon dioxide
64
What is a polymer?
Long molecules made from lots of repeating units (monomers) e.g. plastics, protein, starch
65
What are the properties of polythene?
Flexible Cheap Good insulator
66
What are the properties of polypropylene?
Flexible Does not shatter
67
What are the properties of PVC?
Tough Good insulator Can be flexible
68
What is a condensation reaction?
When organic molecules form and sometimes form a small molecule (usually water) alongside the polymer
69
What are the problems with making polymers?
Made from crude oil - finite, non-renewable, bad for wildlife Non-biodegradable Take up space in landfills Produce toxic gases when burned
70
What are the steps of recycling plastics?
1. Collect waste 2. Sort waste into different polymers 3. Dispose of waste that can't be recycled 4. Clean polymers and grind into chips 5. Purify chips 6. Melt chips and form into a new product
71
How do you perform a flame test?
1. Light bunsen burner and open air hole 2. Clean wire loop in hydrochloric acid 3. Use wire loop to pick up some of the substance that will be tested 4. Hold the sample in flame and observe colour
72
What colour does lithium go in a flame?
Red
73
What colour does sodium go in a flame?
Yellow
74
What colour does potassium go in a flame?
Lilac
75
What colour does calcium go in a flame?
Orange
76
What colour does copper go in a flame?
Blue-green
77
Why is flame photometry used?
Faster and more accurate + sensitive
78
When added to NaOH what colour precipitate does iron(II) form?
Green
79
When added to NaOH what colour precipitate does iron(III) form?
Brown
80
When added to NaOH what colour precipitate does copper form?
Blue
81
When added to NaOH what colour precipitate does calcium form?
White
82
When added to NaOH what colour precipitate does aluminium form?
White
83
How do you tell the difference between calcium and aluminium ions when testing using NaOH?
Add NaOH in excess, white precipitate will go colourless if it's aluminium
84
What is the test for an ammonium cation?
When added to sodium hydroxide and warmed, NH₃ will be produced
85
What is the test for a carbonate ion?
Gives off carbon dioxide when added to HCl
86
What is the test for a sulfate ion?
Do carbonate test Add a few drops of barium chloride which will form a white precipitate
87
What are the tests for halide ions?
Add nitric acid then add a few drops of silver nitrate
88
When testing for halide ions, what colour does chloride go?
White
89
When testing for halide ions, what colour does bromide go?
Cream
90
When testing for halide ions, what colour does iodide go?
Yellow
91
What are the properties of ceramics?
Unreactive Hard and stiff Brittle Poor electrical + thermal conductors High melting points Opaque
92
What are the properties of polymers?
Strong Poor electrical and thermal conductors Chemically unreactive
93
What is concrete made of?
Mix of cement, sand, aggregate and water
94
What is a laminate?
Layering wood to make it strong in all directions
95
What are nanoparticles?
Tiny particles consisting of only a few hundred atoms
96
How big are nanoparticles?
Between 1nm and 100nm
97
What are the uses of nanoparticles?
Socks - silver nanoparticles good at killing bacteria Sunscreen - titanium dioxide nanoparticles absorb harmful UV rays Stain resistant clothing - nanoparticles catalyse breakdown of dirt
98
What are the risks of nanoparticles?
May pose hazard to human health and environment Can be breathed in or pass through skin High SA:V may allow them to catalyse harmful reactions
99
What are the 3 most reactive metals in the reactivity series? (From most reactive)
Potassium Sodium Lithium
100
What are the 3 least reactive metals in the reactivity series? (From least reactive)
Gold Copper Iron

Chemistry (2 decks)

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