Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A-Level Chemistry [OCR B Salters] (sorry for any spelling mistakes - there are many) > [Year 1] DF > Flashcards

[Year 1] DF Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

What are stereoisomers?

A

Isomers with the same structural formula but a different arrangement of atoms in space.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why does stereoisomerism occur in alkenes?

A

The C=C (pi bond) cannot rotate and is rigid.

Thus you get E/Z isomerism.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

When do you get E isomers?

A

When the atoms that are the same are on opposite sides.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

When do you get Z isomers?

A

When the atoms that are the same are on the same sides.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is electrophilic addition?

A

When alkenes are attacked by electrophiles due to their double bonds high electron density.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do you show an electrophilic addition reaction?

A
  • Curly arrow.

- From double bond to positive.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the reaction conditions to react to hydrogen gas with ethene?

A

150⁰C and Nickle catalyst

OR

RT and Platinum catalyst

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How can we test for alkenes?

A

Decoloration of bromine water.

  • Add bromine water to alkene.
  • Brown-orange to colourless.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why does the test for alkenes work?

A
  • Bromine is polarised when it gets near alkene as the electrons in the C=C bond repels electrons in Br₂
  • This make Bromine an electrophile.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happends in the intermediate when testing for alkenes?

A

A carbocation is formed

Br⁻ is formed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Draw the mechanism for the test for alkenes.

A

Google search answer.

FIRST
- Arrow from C=C to δ+ Br

-Arrow from Br-Br to δ- Br

INTERMEDIATE

  • Br bond with C
  • No more double bonds
  • Carbocation shown by C⁺
  • Bromide ion show by Br⁻ with outer electrons shown.

LAST
- 1,2-dibromoalkane drawn.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happend as a result of the hydration of alkenes?

A

Alcohos produced.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What the reaction conditions in the hydration of alkenes?

A

Water must be gas.

300⁰C and 60atm.
Phosphoric acid catalyst (H₃PO₄).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Show the reaction for the hydration of ethene?

A

ethene + water(g) ⇌ ethanol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Other than hydartion how can alcohols be made?

A

Alkyl hydrogen sulfates with sulfuric acid being re-formed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How are alcohols made with alkyl hydrogen sulfates?

A
  • Cold water added to warm ethyl hydrogen sulfate. (hydrolysis)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does the making of alcohols with alkyl hydrogen sulfates show sufuric acid is a catalyst?

A

Sulfuric acid is reformed.

H₂C=CH₂ + H₂SO₄ → CH₃CH₂OSO₂OH

CH₃CH₂OSO₂OH + H₂O → CH₃CH₂OH + H₂SO₄

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How are halogenoalkanes formed?

A

Alkene + Hydrgen Halides.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Give an example of the mechanism to form halogenoalkanes.

use HBr and ethene

A

Google search answer.

FIRST
- Arrow from C=C to δ+ H

-Arrow from H-Br to δ- Br

INTERMEDIATE

  • H bond with C
  • No more double bonds
  • Carbocation shown by C⁺
  • Bromide ion show by Br⁻ with outer electrons shown.

LAST
- bromoethane drawn.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What happends when hydrogen halides react with unsymmetrical alkenes?

A

2 products made

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Give an example of the mechanism between hydrogen halides and unsymmetrical alkenes?

(use HBr and Prop-1-ene)

A

Google search answer.

FIRST
- Arrow from C=C to δ+ H

-Arrow from Br-Br to δ- Br

INTERMEDIATE 1

  • H bond with C
  • No more double bonds
  • Carbocation shown by C⁺
  • Bromide ion show by Br⁻ with outer electrons shown.

[OR] INTERMEDIATE 2

  • H bond with OTHER C
  • No more double bonds
  • Carbocation shown by C⁺
  • Bromide ion show by Br⁻ with outer electrons shown.

LAST 1
- 1-bromopropane drawn.

[OR] LAST 2
- 2-bromopropane drawn.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Alkene monomers join to form _______.

A

Addition polymers.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What happens when monomers form an addition polymer?

A

The double bond is opened.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Draw the addition polymerisation of poly(propene)

A

Google search answer.

  • Repeated unit drawn in brackets.
  • The double bond breaks to form two single bonds extend beyond the brackets.
  • the number, n, is shown outside of the brackets
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are proporties of poly(alkenes)?

A
  • Saturated
  • Non-polar
  • Unreactive

(thus don’t degrade well in landfills)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Why are alkanes good fuels?

A

They can burn in oxygen completely.

They burn readily to produce large amounts of energy.

Longer chains = more energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Show the equation fort he complete cobustion of butane?

A

C₄H₁₀(g) + 6.5O₂(g) → 4CO₂(g) + 5H₂O(g)

[Same for cycloalkanes, alkenes and alcohols]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What do greenhouse gases do to IR?

A

Absorb it.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Summarise the greenhouse effect?

A
  • EM radiation from the sun reaches the earth and is absorbed.
  • Some is re-emmitted as IR.
  • These get absorbed by greenhouse gases and re-emmitted back down to earth.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

List the greehouse gases?

A

Carbon Dioxide.
Water Vapour.
Methane.
Nitrous Oxide.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How have humans contributed to the enhanced greenhouse effect?

A
  • Burnig fossil fules.

- Landfills.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

When does incomplete combustion happen?

A

Burning with a limited oxygen supply.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is produced when alkanes ar burnt incompletely?

A

Carbon monoxide.

Carbon particulate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Show the equation fort he incomplete cobustion of butane producing carbon monoxide?

A

C₄H₁₀(g) + 4.5O₂(g) → 4CO(g) + 5H₂O(g)

[Same for cycloalkanes, alkenes and alcohols]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

How can carbon monoxide be removed?

A

By using a catalytic converter.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What do unburnt hydrocarbons and the oxides of nitrogen contribute to?

A

Photochemical Smog in the toposphere.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How do the burning of fossil fules cause cause acid rain?

A

Burning of fossil fules prodes sulfur dioxide and oxides of nitogen.

This reactsd with water in the atmosphere to form sulfuric and nitric acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is wet scrubbing?

A

Spraying alkiline CaCO₃ or CaO on acidic gases to neutralise them in flue gases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What metals are found in catalytic converters?

A

Platinum.

Rhodium.

(Iridium or palladium).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What harmful gases are converted into what less harmful producs?

A

HARMFUL

  • Carbon Monoxide
  • Oxides of Nitrogen
  • Unburnt Hydrocarbons

LESS HARMFUL

  • Water Vapour
  • Nitrogen
  • Carbon Dioxide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Why is Solar, wind and wave energy nearly carbon neutral?

A

CO₂ emmited through manufacturing.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is the product of a hydrogen fules cell?

A

Water.

43
Q

What are the problems with hydrogen fule cells?

A
  • Hydrogen is difficult to store and transport.
  • Hydrogen is flamible.
  • Hydrogen has a low enrgy:volume ratio.
44
Q

Undert the same conditions what is simlar for gases?

A

They ocupy the same volume of space.

45
Q

How do you work out the number of moles in a gas?

A

Volume (dm³)/Molar Gas Volume

46
Q

What is standard temperature and pressure?

A

298K (25⁰C)

100kPa (101.3kPa)

47
Q

What is the molar volume of gas at standard RTP

A

24dm³mol⁻¹

48
Q

How would you work out the following question:

How much gas in cm³ is produced when 6.2g of Magnesium reacts with hydrochloric acid at r.t.p?

A
  1. Write out equation.
    Mg + 2HCl → MgCl₂ + H₂
  2. Moles of Mg = mass/Mr.
  3. 2/24.3 = 0.255
  4. Using ratio work out mol of gas.
    Mg:H₂ = 1:1 = 0.255:0.255
  5. Work out volume from Moles.
    Vol = Mol x 24 = 0.255 x 24 = 6.12dm³
  6. Convert.
  7. 12dm³ = 6120cm³
49
Q

How would you work out the following question:

Calculate the total volume of gas produced when 5.6dm³ of Nitrous Oxide (N₂O) decomposes.

A
  1. Write out equation.
    N₂O → N₂ + 0.5O₂
  2. Sum moles of gas and express as ratio with reactant.
    1: (1+0.5) = 1:1.5
  3. Express volume as ratio.
  4. 6:x
  5. work out x.
  6. 5 x 5.6 = 8.4dm³
50
Q

What is the ideal gas equation and what do the values mean?

A

pV = nRT

p: pressure (Pa)
V: Volume (m³)
n: Moles (mol)
R: Gas Constant (on data sheet)
T: Temperatur (K)
51
Q

How would you work out the following question:

Calculate the volume in cm³ of 0.36 moles of a gas at 100kPa and 298K.

A
  1. Rearagne pV=nRT.
    V= (nRT)/p
  2. Convert reqired units.
    100kPa = 100,000Pa
  3. Plug value into equation.
    V = (0.36 x 8.31 x 298) / 100000 = 8.91x10⁻³m³
  4. Convert in needed.
  5. 91x10⁻³m³ = 8910cm³
52
Q

How can we measure the volume of a gas?

A

Using a gas syringe.

ONLY is one gas is being produced.

53
Q

What is the enthalpy change of a reation?

A

The heat change in a reaction at a constant pressure.

54
Q

What is the symbol and units for enthalpy change?

A

ΔH

kJmol⁻¹

55
Q

What is the symbol for enthalpy change in standard state under standard conditions?

A

ΔHᴼ

ᴼ =⦵

56
Q

What enthalpy change does an endothermic reaction have?

A

+ΔH

57
Q

What enthalpy change does an exothermic reaction have?

A

-ΔH

58
Q

When is a reaction endothermic?

A

When more energy is needed to form bonds than break bonds.

59
Q

When is a reaction exothermic?

A

When more energy is needed to break bonds than form bonds.

60
Q

What is bond enthalpy?

A

The amount of energy neededto break 1 mole of a bond type in a molecule in the gaseous state.

61
Q

Why might the bond enthalpy of a C-H bond be an averge?

A

Becasue bonds of the same type don’t all have the same amount of energy.

62
Q

Enthalpy Change =

A

= Energy needed to break bonds - Energy needed to from bonds

63
Q

What determids bond enthalpy in covalent molecules?

A
  • Atractive forces between poative nulcei and negative electrons
  • Rupulsive forces between both posative nuclei and between negative electrons being shared.
  • The balence betweenm these opposing forcesd is called the bond length.
  • The greater the electron density between atoms. The stronger the attractive force. Thus the atoms are pulled futher towards eachther.
  • Leading to a shorter bond and a higher bond enthalpy.
64
Q

Describe the change in bond enthalpy between:
C-C
C=C
C≡C

A

As you do down:

  • Higher electron density shared.
  • Thus shorter bond.
  • Thus higher bond enthalpy.
65
Q

What are the four types of enthalpy change?

in DF only

A

ᴼ =⦵

ΔᵣHᴼ = Standard enthapy change of reation.

ΔₙₑᵤₜHᴼ = Standard enthapy change of neutralisation.

Δ꜀Hᴼ = Standard enthapy change of combustion.

ΔfHᴼ = Standard enthapy change of formation.

66
Q

What is the standard enthapy change of reation?

A

The enthalpy change of a reaction acording to the molar quantities in the equation under standard. conditions.

67
Q

What is the standard enthapy change of neutralisation?

A

The enthalpy change when an acid and alkali react to form 1 mole of water, under standard conditions.

68
Q

What is the standard enthapy change of combustion?

A

The enthalpy change when 1 mole of a substance is completely burned in oxygen to make CO₂ and H₂O, under standard condtions.

69
Q

What is the standard enthapy change of formation?

A

The enthalpy change when 1 mole of a compound is formed from its elements in their standard states, under standard conditions.

70
Q

What is Hess’s Law?

A

The total enthalpy change of a reaction is independent of the route taken.

71
Q

How do you construct a Hess’s cycle for formation?

A

IF GIVEN REACTION DATA:

  • Reactants → Products
    with the arrow being Δ꜀H or ΔᵣH
  • Balance equations.
  • Element in standard states below.
  • Arrow from element to reactants and products (both going up) (these are ΔfH)
72
Q

How do you construct a Hess’s cycle for combustion?

A

IF GIVEN COMUSTION DATA:

  • Reactants/Elements → Products
    with the arrow being ΔfH or ΔᵣH
  • Balance equations.
  • Combustion broducts below (CO₂ + H₂O).
  • Arrow from reactans/element and products to cobustion products. (both going down) (these are Δ꜀H)
73
Q

What is calorimetry used for?

A

Used to work out the enthalpy change of combustion.

74
Q

Describe the process of calorimetry?

A
  • Weigh mass of fule.
  • Set up metal can of water with thermomether over the fule.
  • Add lid and wind shield to prevent heat loss and draught movign the flame.
  • Once water has increased by a spesific amount weigh fule.
  • plug data into q=mcΔT
75
Q

What is the calorimetry formula?

A

q=mcΔT

q: energy loss or gained (J)
m: mass (g)
c: Specific heat capacity (4.18 for water)
ΔT: Change in temperature

76
Q

How would you work out the following question:

100g of water was heated from 23⁰C to 57⁰C by 1.8g of ethanol. Calculate the energy transferred and hence the enthalpy change of the fuel.

A
  1. Pulg into q=mcΔT
    q= 100 x 4.18 x 34
    q = 14212J
  2. Convert to kJ
    14212J = 14.212kJ
  3. Work out moles of ethanol with Moles = mass/Mr.
    Moles of ethanol = 1.8/46 = 0.039 mol
  4. Work out enthalpy change (energy change per mole).
    [negative because it’s exothermic]
    -14.212/0.039 = -364.4 kJmol⁻¹
77
Q

How do catalyst effect the rate of reaction?

A
  • Increases the rate of reaction by providing an alternative pathway that has a lower activation energy.
  • The catalyst is chemically unchanged at the end of the reaction.
78
Q

What is cracking?

A

Breaking down longer hydrocarbons into higher demand shorter hydrocarbons.

79
Q

What are heterogeneous catalysts?

A

The catalyst is in a different state to the reactants.

80
Q

Why are catalyst used in industry?

A

To lower the temperature needed for a reaction. Thus less energy is needed so less money is spent.

Speed up th reaction by providing an alternative pathway for the reaction to proceed.

81
Q

What are the environmental benefits of using catalysts?

A

Lower temperatures and pressures means less energy is used so less CO₂/Polutatns are used/produced.

Less waste is produced as it allows you to use reactions with better atom economies.

82
Q

What happens to substances on the surface of solid heterogeneous catalysts?

A

They are aDsorbed

83
Q

Describe the reaction that occurs on solid heterogenoues catalsys.

A
  • The reactants bond with the surface of the catalyst (adsorbtion).
  • The bonds in th reactatns weaken and break to from readicals.
  • The radicals react with eachother to make new substances.
  • The new molecules are then released from the surface of the catalyst (desorption).
84
Q

What can happen to a heterogeneous catalyst to mean it has a reduced effeciveness?

A

They can be poisoned.

E.g. Lead poisons platinum catalsyst in a catalytic converter in a car.

85
Q

Waht does saturated mean?

A

No C=C bonds.

86
Q

What is the general formula for alkanes?

A

CₙH₂ₙ₊₂

87
Q

What is the general formula for cycloalkanes?

A

CₙH₂ₙ

88
Q

Why are alkenes reactive?

A

They have a high electron density.

89
Q

What are arenes?

A

A group of organic molecules with benzene ring structures.

90
Q

What can be call compounds that are arenes?

A

Aromatic compounds.

opposite are aliphatic compound

91
Q

How are electrons in benzene delocalised?

A

The electrons in the double bonds are not attach to any particular carbon.

Thus they are delocalised.

Shown by a circle in a 6 carbon skeleton.

92
Q

What are the prefix/suffix’s for the following homologous series?

Alkanes
Alkanes (branches)
Alkenes
Alcohols
Arenes
Halogenoalkanes
Cyvloalkanes
A

Alkanes
-ane

Alkanes (branches)
alky-

Alkenes
-ene

Alcohols
-ol

Arenes
-benzene

Halogenoalkanes
fluoro-/chloro-/bromo-/iodo-

Cyvloalkanes
cyclo- -ane

93
Q

What shape do alkanes form around a carbon?

A

Tetrahedral

- therfore they zig-zag.

94
Q

What shape do alkenes form around a carbon=carbon bond?

A

Trigonal Planar

- therfore they zig-zag.

95
Q

What is a sigma (σ) bond?

A

When two orbitals overlap, and align horizontally to give a single covalent bond.

96
Q

What is a pi (π) bond?

A

The parallrl overlap of 2 p orbitals.

97
Q

Why are π bonds weaker than σ bonds?

A

The electron density is spread out above and below the nuclei.

Thus the electrostatic attraction between the negative electrons and the posative nuclei is weaker.

This result is a weaker bond and bonf enthalpy.

98
Q

What is the molecular formula fro ethane?

A

C₂H₆

99
Q

What is the shortened structural formula for Butan-1-ol?

A

CH₃CH₂CH₂CH₂OH

100
Q

What are the three types of structural isomerisms?

A
  • Chain.
  • Positional.
  • Functional Group.
101
Q

What is chain isomerism?

A

Same molecular formula but different arrangement of the carbon skeleton.

(Pentane and 2-methylbutane)

  • Similar chemical properties.
  • Different physical properties.
102
Q

What is positional isomerism?

A

Same molecular formula but a different position of the functional group on the carbon skeleton.

(Pantan-1-ol and Pentan-2-ol)

  • Different chemical properties.
  • Different physical properties.
103
Q

What is functional group isomerism?

A

Same molecular formula but a differnt functional group.

(Pent-1-ene and Cyclopentane)

  • Different chemical properties.
  • Different physical properties.

A-Level Chemistry [OCR B Salters] (sorry for any spelling mistakes - there are many) (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions