C8 - rates and equilibrium

Question 1

how can you find out the rate of reactions

Answer 1

how fast it takes or how much reactants that use to make products

Question 2

what is activation energy

Answer 2

the minimum amount of energy needed to start a reaction

Question 3

what is the collision theory

Answer 3

where reactions can only take place when the particles of reactants come together. the reacting particles do not only have to bump into eachother they have to collide with enough energy to cause a reaction to take place

Question 4

how does surface area of a product a reaction rate

Answer 4

the particles inside a large lump of solid are not in contact with the reactant particles in the solution, so not all of the particles inside the large lump doesnt react fully

Question 5

why do smaller lumps increase the reaction rate

Answer 5

many more particles of the solid are exposed to the solution and is able to react alltogether at once in a fast rate

Question 6

what happens to the reaction when you increase the temperature (simple)

Answer 6

goes faster

Question 7

what happens to the reaction when you increase the temperature (yeah)

Answer 7

when you heat up a substance the energy is transferred to its particles which means that the particles move more faster as the temperature increases overtime

Question 8

what happens to the reaction when you increase the pressure

Answer 8

increased pressure squashes the gas particles more closely together. there are more particles of gas in a give space. this increases the chance that they will collide and react

Question 9

what are catalysts

Answer 9

things you can use that increase the rate of reactions

Question 10

give an example of a transition metal which is used as a catalyst

Answer 10

iron

Question 11

how do catalysts work (chemistry way)

Answer 11

they increase rates of reaction by providing an alternative reaction pathway to the products, with a lower activation energy making the reaction more faster

Question 12

advantages to catalysts

Answer 12

saves money and helps the environment and they help to combat climate change

doesn’t get used up during a reaction

Question 13

meaning of reversible reaction

Answer 13

where products can turn back to their reactants

Question 14

How is rate of reaction calculated?

Answer 14

Amount of reactants used or product formed / time

Question 15

Name three common ways of measuring rate of reaction

Answer 15

Loss in mass of reactants

Volume of gas produced

Time for solution to be finished reacting

Question 16

How do you measure the rate by monitoring gas

Answer 16

Connect a gas ryringe to a reaction flask and measure the vol of gas formed in time intervals

Question 17

State 5 factors affecting the rate of a chemical reaction

Answer 17

Concentration of reactants
Pressure of gases
Surface area
Temperature
Catalysts

Question 18

What is collision theory

Answer 18

Chemical reactions can only occur when reacting particles colling with eachother with sufficient energy

Question 19

Describe the affect of increasing temp on the rate of reaction

Answer 19

As temp increases, ke also increases of particles. More energetic collisions, they also move more faster which means that they collide more frequently

Question 20

Describe what is the affect of increasing conc of the rate of reaction

Answer 20

Increases, more reactants = more frequent collisions

Question 21

Describe the rate of reaction when increasing pressure

Answer 21

Similar to increasing conc, it increases the no of gas molecules in the same volume and so increases the frequency of collisions and therefore increases the rate of reaction.

Question 22

Describe affect if increasing SA

Answer 22

If solid reactant are in smaller pieces = greater SA

Question 23

What is a catalysts and how does it work

Answer 23

A catalysts changes the rate of reaction but isnt used up.

It increases the rate of reaction by providimg a different pathway for the reaction that has a lower activation energy

Question 24

What is an enzyme

Answer 24

An enzyme is a molecule that acts as a catalysts in a biological system

Question 25

When is dynamic equilibrium reached

Answer 25

In a closed system, when the forward and reverse reactions occur at the same rate and the conc of reactants and products remain constant

Question 26

What is le chateliers principle

Answer 26

If a system is a equilibrium and a change is made to any of the conditions it will counteract it in the system