DF

Question 1

Is bond making/breaking endothermic or exothermic?

Answer 1

Breaking - endothermic
Making - exothermic

Question 2

What is standard enthalpy change of neutralisation?

Answer 2

1 mol of H+ reacts with 1 mol OH- to form 1 mol of H2O

1moldm-3 conc

Question 3

What is a homologous series?

Answer 3

Compounds that differ by -CH2

Question 4

Why would temperature change be inaccurate for endothermic processes?

Answer 4

Heat taken in

Question 5

Why do diesels produce less hydrocarbons?

Answer 5

Less volatile / higher bp

Question 6

Why could enthalpy change of combustion be different to a book value?

Answer 6

Bond enthalpy is an average
Not in standard states

Question 7

What is enthalpy change of combustion?

Answer 7

1 mole completely burned in oxygen

Question 8

What is enthalpy of formation?

Answer 8

1 mole of compound formed from its elements

Question 9

Which way do the arrows go on a
Formation cycle
Combustion cycle?

Answer 9

Outwards
Inwards (to CO2 + H2O)

Question 10

Chain isomer

Answer 10

Different arrangement of carbon skeleton (branching)

Question 11

Positional isomer

Answer 11

Different position of functional group

Question 12

Functional group isomer

Answer 12

Different functional group

Question 13

Conditions + product of hydrating alkenes

Answer 13

300c
60 atm
Steam + acid catalyst
Alcohol

Question 14

What causes photochemical smog?

Answer 14

Unburnt HC (C) and NOx

Question 15

What causes acid rain?

Answer 15

SO2
NOx

Question 16

Disadvantages of biofuels

Answer 16

Expensive
Land used to grow crops instead

Question 17

What is a sigma bond?

Answer 17

Overlap of s-orbitals
Free rotation

Question 18

What bonding is found in single bonds?

Answer 18

Sigma

Question 19

What bonds are found in a double bond?

Answer 19

One sigma and one pi bond

Question 20

What is a pi bond?

Answer 20

Overlap of p-orbitals

Question 21

What is standard enthalpy change of formation?

Answer 21

One mol of substance formed from its elements

Question 22

What is standard enthalpy change of combustion?

Answer 22

One mol of substance burnt completely in oxygen

Question 23

What are the 4 steps of heterogenous catalysis?

Answer 23

Reactants adsorb to catalyst surface
Bonds weaken/break
New bonds formed between reactants
Product desorbs from catalyst surface

Question 24

Equation for enthalpy change

Answer 24

break + make
(+) + (-)

Question 25

What is the definition of bond enthalpy?

Answer 25

The energy required to break one mole of the bond in gaseous state under standard conditions

Question 26

What is specific heat capacity?

Answer 26

Energy required to raise 1g of substance by 1K without a change of state

Question 26

Calorimetry graph

Answer 26

Temp/time

Question 27

How do you calculate enthalpy change per mole?

Answer 27

Q/moles

Question 28

What is thermal cracking?

Answer 28

High temperature and pressure

Question 29

What is catalytic cracking?

Answer 29

Produces aromatic compounds with carbon rings Lower temp (720K) Normal pressure Hydrocarbon vapour passed over heated catalyst

Question 30

What are the effects of CO?

Answer 30

Toxic --> suffocation

Question 31

What are the effects of NOx/SOx?

Answer 31

Acid rain

Question 32

What are the effects of carbon particulates?

Answer 32

Respiratory problems Global dimming

Question 33

What is a catalytic converter made from?

Answer 33

Rhodium

Question 34

What is an arene?

Answer 34

Aromatic Contains benzene as part of structure

Question 35

What is an aliphatic compound?

Answer 35

No benzene

Question 36

Why is the enthalpy same for isomers?

Answer 36

Same number and same type of bonds broken

Question 37

Why may enthalpy change be different? NOT LOWER

Answer 37

Not standard states Bond enthalpy is an average

Question 38

What is an explanation of Hess' law?

Answer 38

energy change independent of route as long as conditions remain the same