Unit 3

Question 1

What is the definition of feedstock?

Answer 1

A substance derived from a raw material which is used to manufacture another substance

Question 2

What is the definition of raw material?

Answer 2

A useful substance for the chemical industry which is found naturally for example crude oil, water etc.

Question 3

What does Le Chatelier’s Principle? state?

Answer 3

If a system at equilibrium is subjected to any change, the system readjusts itself to counteract the applied change

Question 4

What effect does the addition of reactant or removal of product have on equilibrium position?

Answer 4

Equilibrium shifts to the right

Question 5

What effect does the addition of product or removal of product have on equilibrium position?

Answer 5

Equilibrium shifts to the left

Question 6

What effect does an increase in temperature have on equilibrium position?

Answer 6

Shifts in direction of endothermic reaction

Question 7

What effect does a decrease in temperature have on equilibrium position?

Answer 7

Shifts in direction of exothermic reaction

Question 8

What effect does an increase in pressure have on equilibrium position?

Answer 8

Shifts in direction which reduces the number of molecules in gas phase

Question 9

What effect does a decrease in pressure have on equilibrium position?

Answer 9

Shifts in direction which increases the number of molecules in gas phase

Question 10

What effect does a catalyst have on equilibrium position?

Answer 10

No effect on equilibrium position; equilibrium more rapidly attained

Question 11

What is the definition of a closed system?

Answer 11

Reversible reactions will only reach a state of dynamic equilibrium when the reaction takes place in a reaction vessel that prevents reactants and products escaping

Question 12

What is the definition of equilibrium?

Answer 12

State attained in a reversible reaction when forward and reverse reactions are taking place at the same rate

Question 13

What is the definition of enthalpy of combustion?

Answer 13

The enthalpy of combustion of a substance is the enthalpy change when one mole of the substance is burned completely in oxygen

Question 14

What is the definition of neutralisation of an acid?

Answer 14

The enthalpy change when acid is neutralised to form one mole of water. The enthalpy of neutralisation of a base can be similarly defined.

Question 15

What is the definition of enthalpy of solution?

Answer 15

The enthalpy change when one mole of a substance is dissolved in sufficient water to form a dilute solution

Question 16

What is the definition of Hess’s law?

Answer 16

The enthalpy change of a chemical reaction depends only on the chemical nature and physical state of the reactants and products and is independent of any intermediate steps

Question 17

What is the definition of molar bond enthalpy?

Answer 17

The energy required to break one mole of covalent bonds.