6-The Rate and Extent of Chemical Change (2)

Question 1

What is a rate of chemical reaction?

Answer 1

How fast reactants are changed into products

Question 2

How can you find the speed of rate of reaction?

Answer 2

Measuring quantity of reactants used up or produts formed over time

Question 3

What is the calculation for mean rate of reaction?

Answer 3

mean ror = quantity of reactants used/time take
or
mean ror = quantity of products formed/time taken

Question 4

What does a steeper line on a reaction time graph indicate?

Answer 4

Faster rate of reaction

Question 5

What is the collision theory of reacting particles?

Answer 5

How often they collide

Question 6

What is the quantity of reactant or product measured in?

Answer 6

mass in grams
volume in cm^3

Question 7

What is required for successful collision?

Answer 7

Enough energy

Question 8

What is activation energy?

Answer 8

The minimum amount of energy particles need to collide

Question 9

Why is energy needed in reactions?

Answer 9

To break the bonds in the reactants and start the reaction

Question 10

What is equilibrium in a reversible reaction?

Answer 10

The forward and backward reaction going at the same rate

Question 11

Under what condition can equilibrium only be reached?

Answer 11

Within a closed system

Question 12

What is true when equilibrium lies to the right?

Answer 12

The concentration of products is greater than reactants

Question 13

What is true when equilibrium lies to the left?

Answer 13

The concentration of reactants is greater than products

Question 14

What does the position of equilibrium depend on?

Answer 14

*Temperature
*Pressure
*Concentration

Question 15

What is true about endo and exo reversible reactions?

Answer 15

If reaction is endothermic in one direction it is exothermic in the other direction

Question 16

What is true about energy during endo and exo reversible reactions?

Answer 16

Energy transferred from surroundings by endo is equal to energy transferred to surroundings during exothermic

Question 17

What is Le Chateliers Principle?

Answer 17

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

Question 18

What happens to equilibrium when temperature is decreased?

Answer 18

*Equilibrium move in the exothermic direction to produce more heat
*More products for the exothermic reaction and fewer for the endothermic

Question 19

What happens to equilibrium when temperature is increased?

Answer 19

*Equilibrium move in the endothermic direction to try and decrease heat
*More products for the endothermic reaction and fewer for the exothermic

Question 20

What happens to equilibrium when pressure is increased?

Answer 20

*Equilibrium tries to reduce and shifts to direction with fewer molecules of gas

Question 21

What happens to equilibrium when pressure is decreased?

Answer 21

• Equilibrium tries to increase it and shifts to direction with more molecules of gas

Question 22

What happens if you change concentration of reactants or products?

Answer 22

The system will no longer be at equilibrium

Question 23

What happens if you increase conc of reactants?

Answer 23

More products formed to decrease it

Question 24

What happens if you decrease conc of reactants?

Answer 24

More reactants formed to increase it

Question 25

What are catalysts?

Answer 25

Change the rate of reaction without being used up in the reaction

Question 26

How do catalysts speed up rates of reaction?

Answer 26

Providing a different reaction pathway for a reaction, that has a lower activation energy