Chapter 13: Fuels and Heats of Reaction

Question 1

Define hydrocarbons

Answer 1

Hydrocarbons are compounds consisting of carbon and hydrogen only, bonded together covalently

Question 2

Define homologous series

Answer 2

A homologous series is a family of organic compounds with
-the same general formula
-similar properties
-successive members differing by CH2

Question 3

Do saturated molecules contain double, triple, or single bonds

Answer 3

Single bonds (ONLY)

Question 4

Define structural isomers

Answer 4

Structural isomers are compounds that have the same molecular formula but different structural formulas

Question 5

A reaction in which heat is given out is

Answer 5

exothermic

Question 6

A reaction in which heat is taken in is

Answer 6

endothermic

Question 7

Define heat of reaction

Answer 7

The heat of reaction, delta H, of a chemical reaction is the heat in kilojoules released or absorbed when the number of moles of reactants indicated in the balanced equation describing the reaction react completely

Question 8

Define bond energy

Answer 8

Bond energy is the amount of energy in kJ needed to break one mole of bonds of the same type, all species being in the gaseous state

Question 9

Define heat of combustion

Answer 9

The heat of combustion of a substance is the heat change in kilojoules when one mole of the substance is completely burned in excess oxygen

Question 10

Define kilogram calorific value

Answer 10

The kilogram calorific value of a fuel is the heat energy produced per kilogram of fuel

Question 11

Define heat of formation

Answer 11

The heat of formation is the heat change in kilojoules, when one mole of a substance is formed from its elements in their standard states

Question 12

Define law of conservation of energy

Answer 12

The law of conservation of energy states that energy cannot be created or destroyed but only changed from one form to another

Question 13

Define Hess’s Law

Answer 13

Hess’s law states that the heat change of a reaction depends only on the initial and final states of the reaction and is independent of the route by which the reaction may occur

Question 14

Define auto ignition

Answer 14

Auto-ignition is ignition in an internal combustion engine before a spark is produced

Question 15

Define octane numbers

Answer 15

The octane number is the measure of the tendency of a fuel to auto-ignite or cause knocking

Question 16

Substance with octane number 0

Answer 16

Heptane

Question 17

Substance with octane number 100

Answer 17

2,2,4-trimethylpentane

Question 18

Three factors that contribute to a high-octane compound

Answer 18

1. high degree of branching
2. short chain length
3. existence of rings in the molecule

Question 19

Uses of hydrogen

Answer 19

1. manufacture of ammonia
2. production of margarine from vegetable oils
3. manufacture of HCL
4. production of bio-LPG

Question 20

Ways of producing hydrogen

Answer 20

1. steam reformation
2. electrolysis of water