unit 11 - rate of reaction and equilibrium

Question 1

collision theory

Answer 1

for a sucessfull reaction, particles must collide with sufficient energy in the corrent orientation

Question 2

activation energy

Answer 2

Min. amount of energy required by reacting materials to break down existing bonds and form new ones

Question 3

to increase rate of reaction 2 simplest things to do?

Answer 3

more frequent collision
more successful collisions

Question 4

how to measure activation enegry?

Answer 4

difference between the activation complex and reactants energy

Question 5

how to achieve more frequenct collisions?

Answer 5

increase particle speed or increase particles present

Question 6

how to acheieve more successful collisions?

Answer 6

give particle more energy or lower activation energy

Question 7

how to calculate rate of reaction

Answer 7

Amount of reactant used/time
or
Amount of product formed/time

Question 8

A steeper curve in the reaction graph indicates

Answer 8

a faster rate of reaction

Question 9

whose concentration increases and decreases in a reaction?

Answer 9

concentration of reactants decrease, concentration of products increase

Question 10

why do reactions slow down after some times

Answer 10

fewer reactants left to collide with

Question 11

Increase surface area in ror

Answer 11

increases chance of collisions which means more particles are exposed

Powdered solids react quicker than larger lumps

Question 12

Increase temp in ror

Answer 12

Particles get more energy and reach activation energy faster

Particle speed increases

Question 13

Adding a catalyst in ror

Answer 13

Provide an alternate pathway to travel with less activation energy

Catalyst remain unchanged both physically and chemically

Question 14

what are catalysts

Answer 14

Provide an alternate pathways for the reactant to travel witg lowered activation energy, allowing reaction to take place at lower temp
Help save energy on industrial productions
Are generally transition metals
Remain chemically and physically unchaged after a reaction
Have great economic importance in production

Question 15

Increasing concentration of solution in ror

Answer 15

Results in more frequenct collisions

Low concentrasion = low collisions = slow ror

High concentration = high collisions = fast ror

Question 16

Increase pressure of gas in ror

Answer 16

Brings particles close together
increases frequency of collisons

More particles in a given volume = high pressure = frequent collisions = greater chance of reaction

Question 17

Application of factors affecting ror in the dangers of explosive combustion with fine powders and gases/ Also give example of such dangerous powders used in factories.

Answer 17

An explosion is a very fast reaction that releases a large volume of gaseous products. There is a danger of explosion in factories that handle powdered, flammable substances. These substances include custard powder, flour and powdered sulfur

Question 18

How to calculate ROR using increase in mass of product if product has a gas?

Answer 18

Set up the experiment and attached a gas syringe on top of the conical flask
Mix the reactants and measure the values on the gas syringe at equal time intervals
graph the results of change of mass vs time graph
Find the point where line becomes steady, that point is the point where all reactants are used up and no more extra gas will be produced

Divide that value of change in mass by time taken to reach there to get the rate of reaction

Question 18

what is it called to set the reading on an equipment to zero before an experiment

Answer 18

Caliberating

Question 19

Reversible reactions

Answer 19

Both forward and the reverse reaction can occur as the product molecules can themselves react with each other or decompose and form the reactant molecules again.

Question 20

If the forward reaction is exothermic, the reverse will be

Answer 20

Endothermic as the same amount of heat is transferred in both directions.

Question 21

Equilibrium

Answer 21

A system is said to be in equilibrium when the rate of forward reaction is equal to the rate of the backward reaction and the concentration of reactant and product becomes constant in a reversible reaction in a closed system.

Question 22

More product than reactant, where does equilibrium lie?

Answer 22

Equilibrium lies to the right.

Question 23

More reactant than product, where does equilibrium lie?

Answer 23

Equilibrium lies to the left side.

Question 24

Types of equilibrium

Answer 24

Physical and Chemical.

Question 25

Physical equilibrium

Answer 25

If there is a physical change and only the state changes.

Question 26

Chemical equilibrium

Answer 26

If there is a chemical change and new substance is formed.

Question 27

Example of physical equilibrium reaction

Answer 27

Any hydrated salt breaking down into anhydrous salt + water.

Question 28

Le chatelier's principle

Answer 28

When a system in equilibrium is disturbed, the equilibrium wants to undo the disturbance to go back to equilibrium.

Question 29

What are the factors affecting equilibrium

Answer 29

Temperature, Pressure, Concentration, Catalyst.

Question 30

How does a change in temperature affect the equilibrium

Answer 30

Increasing the temperature shifts the equilibrium to endothermic side. Decreasing the temperature shifts the equilibrium to the exothermic side.

Question 31

How does a change in the pressure affect the equilibrium

Answer 31

An increase in pressure shifts equilibrium toward the side with fewer gas molecules to reduce pressure, as the system tries to counter the change by occupying less volume

Question 32

3H₂ + N₂ ⇌ 2NH₃ where will the equilibrium shift with increase in pressure

Answer 32

3 + 1 = 4 > 2. Hence equilibrium will shift in forward direction, increasing the yield of ammonia.

Question 33

How does a change in the concentration affect the equilibrium

Answer 33

Increasing the concentration of reactants/Decreasing concentration of products = equilibrium shifts in forward direction. Increasing concentration of products/Decreasing concentration of reactant = equilibrium shifts in reverse direction.

Question 34

How does adding a catalyst affect the equilibrium

Answer 34

Add a catalyst = increase rate of forward reaction and backward reaction in the same manner. Adding catalyst means equilibrium will be achieved faster, but they will have no effect on the yield of products/reactants.

Question 35

In an equilibrium graph, what happens to the lines of rate of forward and reverse reaction

Answer 35

The line representing rate of forward reaction gradually decreases before becoming constant. The line representing rate of reverse reaction gradually increases before becoming constant.

Question 36

What is the region called where the rate of forward and backward reactions are not constant, ie the region before equilibrium

Answer 36

Kinetic region.

Question 37

Haber's process

Answer 37

Industrial method for making ammonia (NH₃) from nitrogen (N₂) and hydrogen (H₂) gases at high pressure, moderate temperature and with a catalyst.

Question 38

Why is Haber process important in daily life

Answer 38

Haber process makes ammonia, which is an essential ingredient in the production of fertilizers, which helps grow the crops we eat.

Question 39

how to title a graph?

Answer 39

Y axis vs X axis Dependent Variable vs Independent variables no unit or values