Rate of reaction

Question 1

What is the rate of a reaction

Answer 1

How quickly reactants are used up or products are formed

Question 2

What are the 2 equations for the mean rate of reaction

Answer 2

Mean rate of reaction= quantity of reactant used/time taken

Mean rate of reaction=quantity of product formed/time taken

Question 3

How would you measure volume of gas produces and what is the equation

Answer 3

connect the reaction mixture to a gas syringe
Rate= Volume of gas produced/time taken

Question 4

What are the 3 units for rates of reaction

Answer 4

Mass- g/s
Volume- cm/s
Moles- Mol/s

Question 5

What do steep and shallow gradients mean when calculating rates from graphs

Answer 5

steep gradient- high rate of reaction
Shallow reaction- low rate of reaction

Question 6

How do you calculate the rate of reaction from a graph

Answer 6

draw tangents to curves and Calculate​ ​the​ ​gradient​ ​of​ ​the​tangent​
measure​ ​of​ ​rate​ ​of​ ​reaction​ ​at​ ​a​ ​specific​ ​time (change in y over change in x)

Question 7

What is collision theory

Answer 7

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

Question 8

What is activation energy

Answer 8

The minimum amount of energy that particles must have to
react

Question 9

How does increasing surface area of solids increase rate of reaction

Answer 9

More reactant particles are exposed leading to more frequent collisions

Question 10

How does increasing the pressure increase rate of reaction

Answer 10

Less space between particles means more frequent collisions

Question 11

How does increasing the concentration increase the rate of reaction

Answer 11

more reactant particles in mixture , so more frequent collisions

Question 12

How does increasing temperature increase rate of reaction

Answer 12

1) particles move faster so more frequent collisions
2)particles have more kinetic energy, so collisions more energetic

Question 13

What are catalysts

Answer 13

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

Question 14

What effect do catalysts have on activation energy

Answer 14

Catalysts provide a different pathway for a chemical reaction that has a lower activation
energy.

Question 15

What effect does lowering activation energy have on particles

Answer 15

increases the proportion of particles with energy to react.
More particles will collide with enough energy, so more collisions result in a reaction

Question 16

What is a reversible reaction and what is the symbol

Answer 16

the products of the reaction can react to produce the original reactants
A+B⇌C+D

Question 17

If a reaction is exothermic one way what will be the reaction the other way

Answer 17

endothermic

Question 18

Is the same or different amount of energy transferred each way

Answer 18

Same

Question 19

What is a closed system

Answer 19

Where no reactants or products can escape

Question 20

What is dynamic equilibrium

Answer 20

When a reversible reaction occurs in a closed system,
dynamic equilibrium is reached
when the reactions occur at exactly the same rate in each direction

Question 21

What is the impact of dynamic equilibrium on the amount of reactants and products

Answer 21

the overall amount of products and reactants are constant but not necessarily equal

Question 22

What are the conditions and how can you change them

Answer 22

External environment of a reaction. you can change them by:
Changing the concentration of one of the substances
Changing the temperature of the entire reaction vessel
Changing the pressure inside the vessel

Question 23

What is Le Chatelier’s principle

Answer 23

If a reaction at equilibrium is subjected to a change any of the conditions, the position of equilibrium will move to
counteract the change.

Question 24

What is the effect of increasing the concentration of reactants at dynamic equilibrium

Answer 24

Favors forward reaction

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

Question 25

What is the effect of increasing the concentration of products at dynamic equilibrium

Answer 25

Favours backward reaction

position​ ​of​ ​equilibrium​ ​shifts​ ​towards reactants​ ​so​ ​more​ ​reactant​ ​is​ ​produced​ ​until​ ​equilibrium​ ​is​ ​reached​ ​again

Question 26

What is the effect of increasing the temperature of the surroundings

Answer 26

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

Question 27

What is the effect of decreasing the temperature of the surroundings

Answer 27

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

Question 28

What is the effect of changing pressure in a gaseous reaction

Answer 28

an​ ​increase​ ​in​ ​pressure​ ​will​ ​favour​ ​the​ ​reaction​ ​that
produces​ ​the​ ​least​ ​number​ ​of​ ​molecules​ ​as​ ​shown​ ​by​ ​the​ ​symbol​ ​equation​ ​for
that​ ​reaction

Question 29

What is the effect of increasing pressure

Answer 29

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

Question 30

What is the effect of decreasing pressure

Answer 30

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