The rate and extent of chemical change

Question 1

what is the rate of chemical reaction mean?

Answer 1

how fast the reactants are changed into products.

Question 2

Example of slow rate of reaction ?

Answer 2

rusting of iron , chemical weathering

Question 3

Example of moderate rate of reaction?

Answer 3

magneusium reaction with an acid to produce a gentle stream of bubbles.

Question 4

Example of a fast rate of reaction?

Answer 4

Burning, explosions

Question 5

Graphs for rate of reaction

Answer 5

Page 67

Question 6

What is the collision theory?

Answer 6

the more collisions there are the faster the reaction is.E.g doubling the frequency of collisions doubles the rate.
the energy transferred during a collision.Particles have to collide with enough energy for the collision to be successful.

Question 7

What are the four things the rate of reaction depends on?

Answer 7

temperature
the concentration of a solution or pressure of a gas
surface area
the presence of a catalyst

Question 8

How does increasing temperature incrase rate of reaction?

Answer 8

when the temp is increased, the particles will move faster.If moving faster, they collide more frequently.also the faster they move the more energy they have, so more of the coillisions will have enough energy to make the reaction happen

Question 9

How does increasing the concentration or pressure increase the rate of reaction?

Answer 9

if a solution is made more concentrated, it means there are more particles knocking about in the same volume of water.(or other solvent).This makes collisions between the reactant particles more frequent.

Question 10

How does increasing the surface area increase the rate of reaction?

Answer 10

if one reactant is a solid, then breaking it up into smaller pieces will increase its sufrace area to volume ratio.
this means that for the same volume of the solid, the particles around it will have more area to work on - so there will be collisions more frequently.

Question 11

How does using a catalyst increase the rate of reaction?

Answer 11

they do this by providing an alternative reaction pathway with a lower activation energy .Enzymes are biological catalysts - they catalyse reactions in living things.

Question 12

How to work out mean of reaction rate from graph page 71

Answer 12

71

Question 13

Draw a tangent to find the reaction rate at a particular point. page 71 bottom

Answer 13

71 bottom

Question 14

what is a reversible reaction?

Answer 14

as more and more products are made their concentrations rise, the backward reaction will speed up.Eventually the forward reaction will go at the same rate as the backward reaction - the system is at equilbrium.

Question 15

What does the position of the equilibrium show.

Answer 15

if to the left, the concentration of products is greater than that of the reactants
if to the right,the concentration of reactants is greater than that of the products

Question 16

What determines what side the position of equilibrium is?

Answer 16

temp
the pressure
concentration

Question 17

Is a reversible reaction endothermic or exothermic?

Answer 17

if the reaction is endothermic in one direction, it will be exothermic in the other.

Question 18

What is Le Chatelier’s principle?

Answer 18

the idea that if u change the conditions of a revcersible reaction at equilbrium, the system will try to counteract that change.
can be used to predict the effect of any changes you make to a reaction system.

Question 19

How does temeperature determine the position of Equilibrium?

Answer 19

If you decrease the temperature, the equilibrium will move in the exothermic direction to produce more heat.
If you raise the temperature , the equilibrium will move in the endothermic direction to try and decrease it .

Question 20

How does the pressure determine the position of Equilibrium?

Answer 20

only affects when involving gases
If increase pressure, equil tries to reduce it, moves to direction with fewer molecules of gas
If decrease pressure, equil tries to increase it,move to direction with more molecules of gas.

Question 21

How does concentration determine the position of Equilibrium?

Answer 21

If you increase the concentration of reactants,system tries to decrease it by making more products
If you decrease the concentration of products, systen tries to increase it again by reducing the amount of reactants.

Question 22

Chem-skl

Answer 22

asda

Question 23

What is the mean rate of reaction is equal to?

Answer 23

quantity of reactant used time taken
Or
quantity of product formed time taken

Question 24

What are the quantities of reactants or products measured in?

Answer 24

The quantities can be mass in grams or volume cm^3

Question 25

The units for rate of reaction are ?

Answer 25

g/s or cm^3/s

(HT)mol/s

Question 26

State the factors that affect the rate of reaction

Answer 26

Concentration of reactants in solution

The pressure of reaction gases
The surface area of solid reactants
The temperature
The presence of a catalyst

Question 27

Describe what “collison theory”

Answer 27

A chemical reaction can only take place when reacting particles collide with each other with enough energy

Question 28

What is activation energy??

Answer 28

Activation energy is the minium amount of energy that particles must have to react.

Question 29

How does concentration, pressure and surface area increase rate of reaction?

Answer 29

Increases the number of successful collision

Question 30

How temperature increase rate of reaction?

Answer 30

Temperature increases the number of successful collisions and increases the amount of energy is in the collision

Question 31

How does a catalyst increase the rate of reaction?

Answer 31

Catalysts increase the rate of reaction by providing a different pathway for a reaction

Question 32

With respect o energy what rule does a reversible reaction follow?

Answer 32

If a reversible reaction is exothermic in one direction it will be endothermic in the reverse direction

Question 33

If a reversible reaction takes place in close equipment…

Answer 33

the rate of the forward reaction is the same as the rate of the reverse reaction.This is called equilibtrium

Question 34

Describe Le Chateliers principle

Answer 34

If a reaction is at equilibriumk and a change is made equilibrium will shift to counteract this change.