C6 The Rate And Extent Of Chemical Change

Question 1

How much product?

Answer 1

The amount of product is directly proportional to the amount of limiting reactant used

Question 2

How to measure reaction times?

Answer 2

Loss in mass of reactants over time
Volume of gas produced over time
Time taken for solution to become opaque or coloured

Question 3

Volumes of gas

Answer 3

Either use a glass gas syringe

Or a measuring cylinder upside down in water

Question 4

Rate of reaction

Answer 4

Measures how much product is made each second

Question 5

Mean reaction time equation

Answer 5

Quantity of reactant formed/ time taken
Or
Quantity of product formed/ time taken

Question 6

Factors affecting rate of reaction

Answer 6

Temperature
Concentrations of reactants in solution
Pressure 
Surface area to volume
Catalyst

Question 7

Changing concentrations

Answer 7

sodium thiosulfate and HCl can be used to investigate concentrations.

Question 8

RP: investigate how changes in concentration affect the rates of reactions by a method involving the production of a gas and a method involving colour change

Answer 8

How is the rate of reaction affected when the concentration of acid is changed
More gas is collected when the concentration is greater
sodium thiosulfate and HCl can be used reacted to find a colour compound and testing concentration

Question 9

Increasing the rate of reaction

Answer 9

^concentration
^temperature
^pressure of gases
^surface area

Question 10

Collisions

Answer 10

Chemical reactions take place when reactant particles collide with each other and form new products
Not all collisions are successful, but a reaction takes place when they are successful

Question 11

Activation energy

Answer 11

Minimum energy required for particles to react successfully

Question 12

Collision frequency

Answer 12

The number of successful collisions between reactant particles that happen each second. The more successful collisions the father the rate of reaction

Question 13

Catalyst

Answer 13

A substance that speeds up a reaction
Only needed in small amounts 
Remains unchanged after the reaction
Creates a new pathway for reactions( lower activation energy)
Specific to one reaction

Question 14

Reversible reactions

Answer 14

Products of the reaction can react to make the original reactants again
Forward and backward reaction
Exothermic and endothermic reactions

Question 15

Equilibrium

Answer 15

When the forward and backward reactions occur at exactly the same rate in a closed system

Question 16

Equilibrium at the left

Answer 16

Concentration of reactants is greater than the con of products

Question 17

Equilibrium to the right

Answer 17

If con of reactants is less than con of products

Question 18

Le Chatelier’s principle

Answer 18

If a system is at equilibrium and a change is made to any of the conditions, then the system responds to counteract the change

Question 19

Changing concentrations

Answer 19

If the concentration of a reactant is increased, more products will be formed until equilibrium is reached again
If the concentration of a product is decreased, more reactant will react until equilibrium is reached again

Question 20

Haber process

Answer 20

N2(g) + 3H2(g) = 2NH3(g)

Question 21

If the temperature of a system at equilibrium is increased:

Answer 21

The relative amount of product at equilibrium increases for an endothermic reaction
The relative amount of product at equilibrium decreases for an exothermic reaction

Question 22

If the temperature of a system at equilibrium is decreased:

Answer 22

The relative amount of product at equilibrium decreases for an endothermic reaction
The relative amount of product at equilibrium increases for an exothermic reaction

Question 23

Making ammonia

Answer 23

Forward reaction is exothermic

To increase yield of products the temp needs to be lower

Question 24

Gaseous reactions at equilibrium

Answer 24

Increased pressure shifts equilibrium to side with the small number of molecules
Decreased pressure shifts equilibrium to the side with the largest number of molecules