Physical Chemistry

Question 1

What is the conservation of energy principle?

Answer 1

energy is conserved in chemical reactions

the amount of energy in the universe at the end of a chemical reaction is the same as before the reaction takes place

Question 2

What is an exothermic reaction?

Answer 2

a reaction in which energy is transferred to the surroundings
combustion, oxidation and neutralisation

Question 3

What is an endothermic reaction?

Answer 3

a reaction in which energy is taken in from the surrounding

thermal decomposition, reaction of citric acid and sodium hydrogencarbonate

Question 4

What is activation energy?

Answer 4

minimum amount of energy that particles need to react

Question 5

What is a reaction profile?

Answer 5

a graph which shows the relative enrgies of reactants and products as well as the activation energy

Question 6

State five factors affecting the rate of a chemical reaction

Answer 6

concentration
pressure
surface area
temperature
catalysts

Question 7

What is the collision theory?

Answer 7

chemical reactions can only occour when reacting particles collide with each other with sufficient energy