Developing Fuels(DF)

Question 1

What is an exothermic reaction?

Answer 1

A reaction that releases energy/heat to the surroundings, causing the temperature of the surroundings to increase

Question 2

In an exothermic reaction does the products or reactants have more energy?

Answer 2

Reactants

Question 3

What happens to the difference in energy between reactants and products in an exothermic reaction?

Answer 3

The difference is release to the surroundings

Question 4

What is an endothermic reaction?

Answer 4

A reaction that takes in heat/energy from the surroundings, causing the temperature of the surroundings to decrease

Question 5

In an endothermic reaction does the products or reactants have more energy?

Answer 5

Products

Question 6

What is activation energy?

Answer 6

The miniumum amount of energy that particles must have to react

Question 7

What is a catalyst?

Answer 7

A catalyst is something which increases the rate of reaction, by providing an alternative pathway for the reaction with a lower activation energy, without being used up

Question 8

Why are catalysts not involved in the chemical equation for a reaction?

Answer 8

They are not used up during the reaction

Question 9

What are the benefits of using a catalyst?

Answer 9

-Allows a reaction to happen at a lower temperature=saves energy
-Saves money

Question 10

What is enthalpy ΔH ?

Answer 10

The measure of heat energy in a system

Question 11

How can you calculate enthalpy change?

Answer 11

ΔH =H products- H reactants

Question 12

What is enthalpy change measure in?

Answer 12

kJ mol-1

Question 13

For an exothermic reaction will the enthalpy change be positive or negative?

Answer 13

Negative

Question 14

For an endothermic reaction will the enthalpy change be positive or negative?

Answer 14

Positive

Question 15

What is the equation that links energy released, mass, specific heat capacity and temperature change?

Answer 15

Q = mc∆T

Question 16

Does breaking bonds release or take in energy?

Answer 16

Takes in energy

Question 17

Does making bonds release or take in energy?

Answer 17

Releases energy

Question 18

What happens as bond length decreases?

Answer 18

The bond becomes stronger

Question 19

Why might calculated bond energy value differ from the figure provided?

Answer 19

-Bond energies are average values from several compounds=not always precise
-Bond energies assume all molecules are in a gaseous state

Question 20

If the energy needed to break the bonds is greater than the energy released when the new bonds are made is the reaction endo or exothermic?

Answer 20

Endothermic

Question 21

If the energy needed to break the bonds is less than the energy released when new bonds are made the reaction is the reaction endo or exothermic?

Answer 21

Exothermic

Question 22

Describe how to calcuale the enthalpy change of solution?

Answer 22

1. Place known volume of water into a polystyrene beaker
   2.Add known mass of the other compund to the water and stir
   3.Measure temperature of water before and after

Question 23

Can atoms rotate freely around a single or double bond?

Answer 23

Single bond, in a double bond there is restricted rotation

Question 24

What are stereoisomers?

Answer 24

Molecules with the same structural formula but the atoms have a different spacial arrangment

Question 25

What are the two types of stereoisomers?

Answer 25

E and Z

Question 26

What is Z isomerism?

Answer 26

When the two highest-priority substituents are on the same side of the double bond axis

Question 27

What is E isomerism?

Answer 27

When the two highest-priority substituents are on opposite sides of the double bond axis

Question 28

What is cis-trans isomerism?

Answer 28

Alkenes with exactly two substituents on the double bond - with one on each carbon

Question 29

What is cis isomerism?

Answer 29

When the substituents are on the same side of the carbon double bond

Question 30

What is trans isomerism?

Answer 30

When the substituents are on different sides of the carbon double bond