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Chemistry > GCSE > Flashcards

GCSE Flashcards

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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
Q

A catalyst

A

provides an alternative pathway with lower activation energy

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26
Q

carbon monoxide is

A

poisonous

27
Q

Why is a sun cream with nanoparticles better than one without?

A

better coverage
protects the skin from harmful UV rays

28
Q

Impurities will… the melting point and… the melting range

A

lower, increase

29
Q

Impurities will… the boiling point

A

increase

30
Q

Formulations are used in:

A

cleaning products
fertilisers
fuels
cosmetics
metal alloys

31
Q

Test for sulfate ions

A

add few drops of HCl
add few drops of barium chloride
white precipitate formed if present as barium sulfate formed

32
Q

Test for halide ions

A

add few drops of dilute nitric acid
add few drops of silver nitrate

33
Q

Why should the platinum wire be cleaned before a flame test?

A

so there are no impurities

34
Q

Advantages of instrumental methods (like electroscopes) for chemical analysis:

A

faster
more accurate
require very small amount of sample to measure - more sensitive

35
Q

The only metal ions that produce a colour other than white in sodium hydroxide are:

A

copper - blue
iron 2 - green
iron 3 - brown (think rust - which is iron 3 oxide)
aluminium - white to colourless

36
Q

If no more carbon dioxide gas is produced when calcium carbonate reacts with hydrochloric acid then:

A

they have stopped reacting
as calcium carbonate has been used up

37
Q

1 or more chains of polypeptides is a

A

protein

38
Q

In a hydrogen fuel cell, the voltage is dependent on:

A

type of electrodes (want 1 reactive and 1 less reactive for max voltage)
type of electrolyte
temperature of electrolyte
concentration of electrolyte

39
Q

You can store hydrogen by:

A

compressing it under high pressures
cooling it

40
Q

Create a 6V battery with 1.5V cells

A

connect 4 1.5V cell in series

41
Q

Non-rechargeable batteries run out because

A

reaction stops
as reactant is used up

42
Q

Distilled water is

A

pure

43
Q

Carbon/soot can cause… in humans

A

respiratory problems

44
Q

Acid rain damages

A
  • buildings and statues
  • aquatic animals as it can make lakes acidic - destorying habitats
  • trees
45
Q

Sustainability

A

​Development that meets the needs of current generations without compromising the ability of future generations to meet their own needs

46
Q

Solar energy is sustainable because

A

it is renewable

47
Q

Solar energy may not meet current electricity demands because:

A
  • sunshine is unreliable
  • not enough space
  • increased demand for energy
48
Q

Lead is

A

toxic

49
Q

Pros of recycling copper

A
  • recycling saves energy
  • recycling conserves reserves of copper ore
  • recycling reduces waste going to landfill sites
  • mining/quarrying damages habitats
50
Q

How is glass recycled?

A

separated by colour and chemical composition
crushed
melted
and reshaped into new glass objects

51
Q

Bioleaching

A

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
Q

Leachate

A

solution produced by bioleaching

53
Q

Phytomining

A

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
Q

Why is phytomining not used often?

A

takes a long time - slow
land not available
high grade ores still available

55
Q

Methods of desalinating salty water - with loads of energy

A

distillation
reverse osmosis

56
Q

Potable water

A

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
Q

Obtaining fresh water from wastewater is more difficult because:

A

it requires more processes
as it contains more microbes and more toxic chemicals

58
Q

Why is producing drinking water from salt water expensive?

A

it requires lots of energy

59
Q

Alloys are… than pure metal

A

harder

60
Q

A stronger acid has a … ph which means it has a … concentration of …

A

very low
higher concentration
H+ ions

61
Q

If the reaction is reversible, then the acid is … + why?

A

weak
as partial ionisation

62
Q

Why does a strong acid have a faster rate of reaction?

A

higher concentration of H+ ions
so more collisions per second

63
Q

Write an ionic equation for the neutralisation of hydrochloric acid with
potassium hydroxide.

A

H+ + OH- —> H2O

64
Q

Why is a metal oxide or carbonate added to an acid until it is in excess?

A

to make sure all the acid reacts

Chemistry (8 decks)

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