Developing fuels definitions

Question 1

Activation energy

Answer 1

The minimum energy required for a reaction to take place.

Question 2

Exothermic reactions

Answer 2

They are often spontaneous reactions and release energy to surroundings, resulting products having lower energy than reactants.

Question 3

Endothermic reactions

Answer 3

They take in energy from the surroundings and products have more energy than reactants.

Question 4

Standard enthalpy change of combustion and the value.

Answer 4

The enthalpy change when one mole of a substance is burnt completely in oxygen under standard conditions.
The value is always:
-2802KJmol-1

Question 5

Standard enthalpy change of formation and the value.

Answer 5

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

-74.8KJmol-1
Zero

Question 6

Standard enthalpy change of neutralisation

Answer 6

Enthalpy change when 1 mole of H+ ions reacts with 1 mole of OH- ions forming one mole of water under standard conditions and in solutions of 1moldm-3.

Question 7

Standard conditions

Answer 7

1atm
298K (25C)
1moldm-3

Question 8

Average bond enthalpy

Answer 8

Enthalpy change of breaking one mole of bonds in gaseous molecules.

Question 9

What are structural isomers

Answer 9

Same molecular formula different structural formula.

Question 10

Homologous series

Answer 10

Series of compounds with the same functional group, each successive member differs by CH2.

Question 11

Aliphatic compounds

Answer 11

Compounds containing C and H joined together in straight chains, branched chains or non-aromatic rings (cycloalkanes/enes)

Question 12

Aromatic Compounds

Answer 12

compound containing a benzene (arene) ring

Question 13

Catalytic Cracking

Answer 13

Cracking converts less useful long chain hydrocarbons that are in high supply into more useful shorter hydrocarbons.

Question 14

Homogenous catalyst

Answer 14

Same physical state as the reactants (esterification reactions)

Question 15

Heterogenous catalysts

Answer 15

Different physical state to the reactants (iron in the Haber process)

Question 16

Heterogenous catalysts work as follows:

Answer 16

• Reactant gas adsorbs onto catalyst surface
• bond in reactants weaken and break
• new product bonds form
• product molecules desorb from catalyst surface

Question 17

Double bond

Answer 17

Consist of one Pi bond and one sigma bond.

Question 18

Stereoisomers

Answer 18

Compounds with the same structural formula but a different arrangement in space.

Question 19

E/Z isomers

Answer 19

No free rotation around C=C bond. Two different groups attached to each carbon atom of the C=C double bond, including H.

Question 20

Cis-Trans Isomers

Answer 20

Special case of E/Z, one group attached to carbon are the same.

Question 21

Electrophile

Answer 21

Molecule or positive ion that accepts electron pairs to form a covalent bond.

Question 22

Carbocation

Answer 22

A carbon atom with a positive charge