paper 2

Question 1

what is the only type of line in chemistry that will be curved on a graph

Answer 1

rate of reaction

Question 2

what are factors that affect the rate of chemical reaction

Answer 2

concentration
pressure
surface area
temperature
catalysts

Question 3

what is the collision theory

Answer 3

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

Question 4

what is activation energy

Answer 4

the minimum amount of energy that particles must have to react

Question 5

how can you increase the rate of reaction

Answer 5

● Increasing the concentration of reactants in solution, the pressure of reacting
gases, and the surface area of solid reactants increases the frequency of
collisions and so increases the rate of reaction.
● Increasing the temperature increases the frequency of collisions and makes the
collisions more energetic, and so increases the rate of reaction.

Question 6

what are catalysts

Answer 6

Catalysts are substances that speed up chemical reactions without being
changed or used up during the reaction

Question 7

what are enzymes

Answer 7

biological catalysts

Question 8

what do catalysts do

Answer 8

Catalysts decrease the activation energy;
this increases the proportion of particles with
energy to react.
Catalysts provide a different pathway for a
chemical reaction that has a lower activation
energy

Question 9

what is a reversible reaction

Answer 9

the products of the reaction can react to produce
the original reactants
The direction of the reaction can be changed by changing the conditions

Question 10

energy changes and reversible reactions (about exo and endo reactions)

Answer 10

If a reversible reaction is endothermic one way, it is exothermic in the opposite
direction.
The same amount of energy is transferred each way

Question 11

the effects of changing conditions on equilibrium

Answer 11

If​ ​a​ ​system​ ​is​ ​at​ ​equilibrium​ ​and​ ​a​ ​change​ ​is​ ​made​ ​to​ ​any​ ​of​ ​the​ ​conditions,
then​ ​the​ ​system​ ​responds​ ​to​ ​counteract​ ​the​ ​change​ ​(Le​ ​Chatelier’s​ ​principle)

Question 11

what happens if the concentration of the reactants is increased

Question 11

what happens when a reversible reaction occurs in a closed system

Answer 11

equilibrium is reached
when the reactions occur at exactly the same rate in each direction

Question 11

if the conc of reactants is increased what happens

Answer 11

​position​ ​of​ ​equilibrium​ ​shifts
towards​ ​products​ ​so​ ​more​ ​product​ ​is​ ​produced​ ​until​ ​equilibrium​ ​is​ ​reached
again

Question 11

if the conc of products is increased what happens

Answer 11

​position​ ​of​ ​equilibrium​ ​shifts
towards​ ​products​ ​so​ ​more​ ​product​ ​is​ ​produced​ ​until​ ​equilibrium​ ​is​ ​reached
again

Question 12

what happens if temp is increased

Answer 12

equilibrium​ ​moves​ ​in​ ​the​ ​direction​ ​of​ ​the endothermic​ ​reaction

Question 12

what happens if temp is decreased

Answer 12

​equilibrium​ ​moves​ ​in​ ​the​ ​direction​ ​of​ ​the exothermic​ ​reaction

Question 13

what happens if pressure is increased

Answer 13

equilibrium​ ​shifts​ ​to​ ​side​ ​of​ ​equation​ ​with​ ​fewer​ ​moles of​ ​gas​

Question 14

what happens if pressure is decreased

Answer 14

​equilibrium​ ​will​ ​shift​ ​to​ ​side​ ​of​ ​equation​ ​with​ ​more moles​ ​of​ ​gas

Question 15

look at pmt for circuit symbols and memorise them

Question 16

what must be for a charge to be able to flow

Answer 16

Circuit must be closed (no open switches)
There must be a source of potential difference (battery/cell)

Question 17

what is current

Answer 17

flow of electrical charge