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GCSE Flashcards

1
Q

How would you ensure no heat is lost when measuring temperature?

A

Insulate the funnel to prevent heat loss/temperature drop

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2
Q

Evidence of a chemical reaction:

A

energy given out
flame produced
precipitate/powder formed
new substance formed

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3
Q

Uses of nanoparticles:

A
  • wound dressings and surgical masks - silver nanoparticles have antibacterial properties and are added to polymer chains
  • high SA:V means they can be used as catalyst
  • can be used in electrical circuits - some nanoparticles conduct electricity
  • in sunscreen
  • nanomedicine - fullerenes are absorbed by the body easier so can be used to deliver drugs to cells
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4
Q

Pure substance

A

contains one element or one compound

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5
Q

Types of bonding:

A
  • covalent - the electrostatic force of attraction between positively charged nuclei and the shared pair of electrons
  • ionic - the electrostatic force of attraction between oppositely charged ions
  • metallic - the electrostatic force of attraction between positive metal ions and the delocalised electrons
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6
Q

Why does the rate of reaction slow down between hydrochloric acid and marble chips?

A

acid is used up
so concentration decrease
so fewer collisions per second
so rate decreases

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7
Q

Why does the separator when making industry ethanol contain ethanol + water?

A

both the water vapour and the ethanol condense

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8
Q

Transition metals vs Alkali metals

A

Transition metals are:
- denser
- less reactive
- have higher boiling point
- stronger
- conduct heat and electricity
- harder
- form coloured compounds

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9
Q

Ionic compounds properties

A
  • strong bonds - high melting + boiling points
  • form lattice structure
  • do not conduct when solid but do when molten or in an aqueous solution
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10
Q

Mendeleev left gaps for

A

undiscovered elements

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11
Q

Why is it important for a company to calculate the mass of product made?

A
  • to know how much product they will make
  • so no reactant is wasted
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12
Q

Properties of noble gases:

A
  • inert (unreactive) so non-flammable
  • colourless gases
  • monatomic gases
  • full outer shell (8 electrons)
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13
Q

What is galvanising?

A

it involves covering iron or alloys of iron (steel) with zinc.
Zinc prevents moisture and air from reacting with the iron causing it to rust.
If the zinc coating gets scratched, the zinc will still corrode instead of the iron as it is more reactive - this is sacrificial protection

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14
Q

How does aluminium not corrode?

A

aluminium reacts with the oxygen in the air to form a thin layer of aluminium oxide which coats the metal.

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15
Q

If it shows graphite and asks for its element, what is the element?

A

carbon

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16
Q

Why are alloys stronger than metals?

A

contain different sized atoms
which disrupts the layers
so layers can’t slide

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17
Q

Alloys are a…

A

mixture

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18
Q

What are the 2 ways to obtaining a soluble salt from a solution?

A
  • evaporation - heat to evaporate the solvent, crystals will appear, continue to heat until all solvent is evaporated
  • crystallisation - heat until crystals just start to form and allow to cool
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19
Q

What reaction conditions can affect the properties of an alkene?

A

temperature
pressure
catalyst

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20
Q

Conditions needed for iron to rust:

A

iron + oxygen + water —> hydrated iron(III) oxide

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21
Q

Corrosion only happens at the

A

surface, where the metal is exposed to air
but the rust/corroded metal flakes off - as it is soft - so a new area is exposed

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22
Q

Corrosion only happens at the

A

surface, where the metal is exposed to air
but the rust/corroded metal flakes off - as it is soft - so a new area is exposed

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23
Q

Nanoparticles contain how many atoms?

A

a few 100 - so are therefore 100x larger than atoms

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24
Q

H20 IS NOT H2 so must be a

A

liquid

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25
A catalyst
provides an alternative pathway with lower activation energy
26
carbon monoxide is
poisonous
27
Why is a sun cream with nanoparticles better than one without?
better coverage protects the skin from harmful UV rays
28
Impurities will... the melting point and... the melting range
lower, increase
29
Impurities will... the boiling point
increase
30
Formulations are used in:
cleaning products fertilisers fuels cosmetics metal alloys
31
Test for sulfate ions
add few drops of HCl add few drops of barium chloride white precipitate formed if present as barium sulfate formed
32
Test for halide ions
add few drops of dilute nitric acid add few drops of silver nitrate
33
Why should the platinum wire be cleaned before a flame test?
so there are no impurities
34
Advantages of instrumental methods (like electroscopes) for chemical analysis:
faster more accurate require very small amount of sample to measure - more sensitive
35
The only metal ions that produce a colour other than white in sodium hydroxide are:
copper - blue iron 2 - green iron 3 - brown (think rust - which is iron 3 oxide) aluminium - white to colourless
36
If no more carbon dioxide gas is produced when calcium carbonate reacts with hydrochloric acid then:
they have stopped reacting as calcium carbonate has been used up
37
1 or more chains of polypeptides is a
protein
38
In a hydrogen fuel cell, the voltage is dependent on:
type of electrodes (want 1 reactive and 1 less reactive for max voltage) type of electrolyte temperature of electrolyte concentration of electrolyte
39
You can store hydrogen by:
compressing it under high pressures cooling it
40
Create a 6V battery with 1.5V cells
connect 4 1.5V cell in series
41
Non-rechargeable batteries run out because
reaction stops as reactant is used up
42
Distilled water is
pure
43
Carbon/soot can cause... in humans
respiratory problems
44
Acid rain damages
- buildings and statues - aquatic animals as it can make lakes acidic - destorying habitats - trees
45
Sustainability
​Development that meets the needs of current generations without compromising the ability of future generations to meet their own needs
46
Solar energy is sustainable because
it is renewable
47
Solar energy may not meet current electricity demands because:
- sunshine is unreliable - not enough space - increased demand for energy
48
Lead is
toxic
49
Pros of recycling copper
- recycling saves energy - recycling conserves reserves of copper ore - recycling reduces waste going to landfill sites - mining/quarrying damages habitats
50
How is glass recycled?
separated by colour and chemical composition crushed melted and reshaped into new glass objects
51
Bioleaching
bacteria convert copper compounds to soluble copper compounds - which separate the copper from the ore the leachate contains copper ions and can be extracted through electrolysis or displacement with scrap iron
52
Leachate
solution produced by bioleaching
53
Phytomining
grow plants in soil containing copper ions copper builds up on leaves - can't be used by plants the plant is harvested, dried and burnt ash produced contains copper ions and is dissolved into acid solution is electrolysed
54
Why is phytomining not used often?
takes a long time - slow land not available high grade ores still available
55
Methods of desalinating salty water - with loads of energy
distillation reverse osmosis
56
Potable water
water taken from rivers or aquifiers it is screened pass through wire mesh to remove large solid bits - e.g. twigs pass through bed of sand + gravel - to remove undissolved solids sterilise it using ozone, chlorine gas or UV rays to kill microbes
57
Obtaining fresh water from wastewater is more difficult because:
it requires more processes as it contains more microbes and more toxic chemicals
58
Why is producing drinking water from salt water expensive?
it requires lots of energy
59
Alloys are... than pure metal
harder
60
A stronger acid has a ... ph which means it has a ... concentration of ...
very low higher concentration H+ ions
61
If the reaction is reversible, then the acid is ... + why?
weak as partial ionisation
62
Why does a strong acid have a faster rate of reaction?
higher concentration of H+ ions so more collisions per second
63
Write an ionic equation for the neutralisation of hydrochloric acid with potassium hydroxide.
H+ + OH- ---> H2O
64
Why is a metal oxide or carbonate added to an acid until it is in excess?
to make sure all the acid reacts

Chemistry (8 decks)

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