Rate Of Reaction

Question 1

What are some examples of slow reactions

Answer 1

Rusting iron

Chemical weathering- like acid rain damage to limestone buildings

Question 2

How can you find the speed of a reaction

Answer 2

Recording the amount of product formed or the amount of reactant used up over time

Question 3

What must happen to particles in order to react

What’s it called

Answer 3

They must collide with enough energy

Collision theory

Question 4

What’s the minimum amount of energy that particles need to react called

Answer 4

Activation energy

Question 5

What 4 things do rates of reactions depend on

Answer 5

Temperature
Concentration of a solution or the pressure of gas
Surface area
Presence of a catalyst

Question 6

Why does pressure in gas increase collisions

Answer 6

Means the same number of particles occupies a smaller space

Question 7

How do catalysts work

Answer 7

Decreasing the activation energy needed for the reaction to occur, they procedure an alternative reaction pathway with a lower activation energy

Question 8

What three ways can you measure the rates of reaction

Answer 8

Precipitation and colour change
Change in mass (usually has given off)
Volume of gas given off

Question 9

How do you work out the mean rate of a reaction

Answer 9

Work out the over all change in the y value then divide this by total time taken for the reaction

Change in y / change in x

Question 10

How do you use a tangent to find a rate of reaction on a graph on a particular point

Answer 10

Draw a tangent on the curve at that particular point

Then work out the gradient of the tangent

Question 11

What’s equilibrium

Answer 11

When the forward and backward reaction are going at the same rate

Question 12

What’s a dynamic equilibrium

Answer 12

Both reactions are still happening but there’s no overall effect
So concentrations of reactants and products have traced a balance and won’t chnage

Question 13

What’s a closed system

Answer 13

None of the reactants of products can escape and nothing else can get in, in a reversible reaction
This will allow equilibrium to happen

Question 14

What does the position of equilibrium depend on

Answer 14

Temperature
Pressure
Concentration of reactants and products

Question 15

What 2 things can reversible reactions be

Answer 15

Endothermic and exothermic

Question 16

What’s it mean by reversible reactions being exothermic and endothermic

Answer 16

Energy transferred from the surrounding by the endothermic reaction is equal to the energy transferred to the surrounding during the exothermic reaction

Question 17

What is Le Chateliers principles

Answer 17

The idea that if you change the conditions of a reversible reaction at equilibrium, the system will try to counteract that change

Question 18

How do reversible reactions counteract the changes in temperature

Answer 18

If u decrease the temp the equivalent will move in the exothermic direction to produce more heat, so more Products for the exothermic reaction
The oppisite will happen if you raise the temperature, equilibrium will
Life in the endothermic direction

Question 19

How to reversible reactions counteract the changes in pressure

Answer 19

If you increase pressure, equilibrium will try to reverse it by moving in the direction where there are fewer molecules of gas
If you decrease it, equilibrium will try to increase it

Question 20

How to reversible reactions counteract the changes in concentration

Answer 20

If you change the concentration the system will no longer be at equilibrium so system responds by trying to get it back
If increased concentration of reactants, it tries to decrease by making more products
And the opposite happens with more products