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A Level Chemistry Year 1 > Reactions and Calculations > Flashcards

Reactions and Calculations Flashcards

1
Q

What are acids also known as?

A

Proton donors

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2
Q

Why are acids also called proton donors?

A

Because when mixed with water, they release Hydrogen ions (as Hydrogen ions have lost an electron, so they’re just a proton)

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3
Q

What are bases also known as?

A

Proton acceptors

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4
Q

Why are bases also called proton accepters?

A

Because they accept Hydrogen ions

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5
Q

What is an alkali?

A

A base that is soluble in water

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6
Q

What do alkalis release in a solution?

A

Hydroxide ions

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7
Q

What is HCl?

A

Hydrochloric Acid

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8
Q

What is H2SO4?

A

Sulfuric Acid

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9
Q

What is HNO3?

A

Nitric Acid

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10
Q

What is CH3COOH?

A

Ethanoic Acid

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11
Q

What is NaOH?

A

Sodium Hydroxide

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12
Q

What is KOH?

A

Potassium Hydroxide

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13
Q

What is NH3?

A

Ammonia

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14
Q

What’s different about the reaction between an acid and water, or a base and water?

A

It’s reversible so both the forwards and backwards reactions will be happening at the same time

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15
Q

What is H3O +?

A

A Hydronium ion (produced when strong acids react fully with water)

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16
Q

What is a strong acid/base?

A

An acid/base that almost completely ionises in water

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17
Q

What is a weak acid/base?

A

An acid/base that only partially ionises in water

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18
Q

Why do strong acids completely ionise in water?

A

Very little of the reverse reaction occurs, meaning nearly all the acid will dissociate (or ionise) in water and so nearly all the H+ ions are released

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19
Q

Why do strong bases completely ionise in water?

A

They favour the forwards reaction, so nearly all the bases dissociates in water and lots of OH- ions are released

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20
Q

Why do weak acids only partially ionise in water?

A

They favour the backwards reaction, and so only a small amount of the acid will dissociate in water and only a few H+ ions are released

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21
Q

Why do weak bases only partially ionise in water?

A

They favour the backwards reaction, and so only a small amount of the base dissociates in water and only a few OH- ions are released

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22
Q

Acid + Base = ?

A

Salt + Water

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23
Q

Metal + Acid = ?

A

Salt + Hydrogen

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24
Q

Metal Oxide + Acid = ?

A

Salt + Water

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25
Q

Metal Hydroxide + Acid = ?

A

Salt + Water

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26
Q

What is a salt?

A

A compound formed when the Hydrogen in the acid molecule is replaced by a positive ion (metal ion or ammonium ions)

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27
Q

What type of reaction is an Acid + Base reaction?

A

A neutralisation reaction

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28
Q

Are Metal Hydroxides normally alkalis or bases?

A

Alkalis

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29
Q

Metal Carbonate + Acid = ?

A

Salt + Carbon Dioxide + Water

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30
Q

What does a solid salt consist of?

A

A lattice of positive and negative ions (and water in some)

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31
Q

What is water of crystallisation?

A

The water in a lattice

32
Q

What is a hydrated salt?

A

A salt that contains water of crystallisation

33
Q

What is a anhydrous salt?

A

A salt that doesn’t contain water of crystallisation

34
Q

What are the 5 steps to find the formula of a hydrated salt?

A
  • Find the mass of the water lost (by subtracting the mass of the anhydrous salt away from the mass of the hydrated salt)
  • Find the number of moles of water lost
  • Find number of moles of anhydrous salt produced
  • Work out the ratio of the above
  • Make the ratio equivalent to 1:n (and then round off n)
35
Q

What are titrations used for?

A

To find out exactly how much acid is needed to neutralise a quantity of alkali

36
Q

What is the first thing you do when performing a titration?

A

Do a rough titration

37
Q

Why do you do a rough titration first?

A

To get an idea where the end point is (where neutralisation occurs)

38
Q

What indicator do you use when doing a titration?

A

Phenolphthalein (Pink to colourless)

39
Q

What is the titre?

A

The volume of acid used to neutralise the alkali

40
Q

What is a standard solution?

A

A solution that has a precisely known concentration

41
Q

What equation links moles, concentration and volume (cm^3)?

A

Moles = (Concentration x Volume)/1000

42
Q

What equation links moles, concentration and volume (dm^3)?

A

Moles = Concentration x Volume

43
Q

How do you convert from cm^3 to dm^3?

A

Divide by 1000

44
Q

What are polyprotic acids?

A

Acids that donate more than one proton

45
Q

What are 2 categories of polyprotic acids?

A 
Diprotic Acids (donate 2 protons e.g. Sulfuric Acid... H2SO4)
Triprotic Acids (donate 3 protons e.g. Phosphoric Acid... H3PO4)
46
Q

Compared to monoprotic acids, how many times of moles will you need to neutralise a diprotic acid?

A

2 times as many moles

47
Q

What is theoretical yield?

A

The mass of product that should be formed in a chemical reaction

48
Q

What does theoretical yield assume?

A

That no chemicals are lost in the process

49
Q

What are the 3 steps to find theoretical yield?

A
  • Work out how many moles of the limiting reactant you have
  • Use the chemical equation to work out how many moles of product you would expect that much of reactant to make
  • Calculate the mass of that many moles of product
50
Q

How does actual yield compare to theoretical yield?

A

For any reaction, it is always less

51
Q

What are 2 reasons why the actual yield is less than the theoretical yield?

A

Sometimes not all the ‘starting’ reactants react fully

Some chemicals are always ‘lost’ (e.g. lost between transferring between containers)

52
Q

What is percentage yield?

A

The actual amount of product you collect, written as a percentage of the theoretical mass

53
Q

What equation links percentage yield, actual yield and theoretical yield?

A

Percentage yield = (Actual yield / Theoretical Yield) x 100

54
Q

What is atom economy?

A

A measure of the proportion of reactant atoms that become part of the desired product in the balanced chemical equation

55
Q

What equation links % atom economy, molecular mass of desired product and sum of molecular masses of all products?

A

% atom economy = (Molecular mass of desired product / Sum of molecular masses of all products) x 100

56
Q

What happens in an addition reaction?

A

The reactants combine to form a single product

57
Q

What is the atom economy (as a %) for an addition reaction?

A

100%, since no atoms are wasted

58
Q

What happens in a substitution reaction?

A

Some atoms from one reactant are swapped with atoms from another reactant

59
Q

What does a substitution reaction form?

A

2 products - the desired product and at least one by-product

60
Q

What is the atom economy (as a %) for a substitution reaction?

A

Always less than 100%

61
Q

What does it mean if something is sustainable?

A

It can occur over a long period of time, without damaging the environment or depleting limited natural sources

62
Q

What does a low atom economy cause?

A

A large amount of waste to be produced

63
Q

What is the oxidation number (oxidation state) of an element?

A

The total number of electrons it has donated or accepted to form an ion or part of a compound

64
Q

What is the oxidation number of uncombined elements (and elements bonded to identical elements)?

A

0 - As they haven’t accepted or donated any electrons

65
Q

What is the oxidation number of a simple monatomic ion?

A

The same as it’s charge

66
Q

How do you find the oxidation number of molecular ions?

A

Sum all of the oxidation numbers of all the atoms in the molecule

67
Q

What is the sum of the oxidation numbers in a neutral compound equal to?

A

0

68
Q

What are the 2 exceptions for the oxidation numbers of oxygen?

A 
When in peroxides = -1
Molecular oxygen (O2) = 0
69
Q

What are the 2 exceptions for the oxidation numbers of Hydrogen?

A 
When in metal hydrides = -1
Molecular Hydrogen (H2) = 0
70
Q

How do you write an element that has different oxidation numbers?

A

With Roman Numerals e.g. (I) = +1

71
Q

What is a loss of electrons called?

A

Oxidation

72
Q

What is a gain of electrons called?

A

Reduction

73
Q

What is a redox reaction?

A

A reaction where oxidation and reduction occurs simultaneously

74
Q

What is an oxidising agent?

A

Something that accepts electrons and get’s reduced

75
Q

What is a reducing agent?

A

Something that donates electrons and get’s oxidised

76
Q

When an element is reduced, it’s oxidation number is reduced

A

:)

77
Q

Give an example of a redox reaction

A

When metals react with acids

A Level Chemistry Year 1 (9 decks)

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