equilibria, rate of reaction

Question 1

what is exothermic reaction

Answer 1

release thermal energy, surrounding heat up

Question 2

what is endothermic reaction

Answer 2

take in energy, surroundings cool down

Question 3

enthalpy change in endo and exo reactions

Answer 3

in exo its negative, endo is positive

Question 4

what is the transfer of thermal energy during a reaction called?

Answer 4

enthalpy change

Question 5

what is activation energy

Answer 5

the minimum energy that colliding particles must ave to react

Question 6

endo and exo in terms of bonds

Answer 6

endo is in bond breaking, in which energy is used to do so and exo is in bond making, no energy is needed to make bonds

Question 7

what is the law pf energy to break or make bonds

Answer 7

always same amount of energy needed to produce or make bonds

Question 8

what does this symbol represent? ⇌

Answer 8

reversible reaction, occurs in both the forward and backward direction

Question 9

what happens if forward reaction is exo

Answer 9

backward is endo

Question 10

what colour change occurs if anhydrous copper sulfate was added to water

Answer 10

white to blue

Question 11

what colour change occurs in anhydrous cobalt chloride was added to water

Answer 11

blue to pink

Question 12

what is dynamic equilibrium

Answer 12

Revirsable reactions that take place in a closed system
-the forward and backward reactions occur at same rate
-the concentrations of reactants and products are no longer changing

Question 13

what is the process to reach dynamic equilibrium

Answer 13

at start there are reactants only no products,
rate of reactants being used up increases and rate of products being used up decreases
rate of forward and backward reaction is the same

Question 14

what happens to rate of reaction if temperature increases

Answer 14

The rate of reaction is faster/ increases because kinetic energy is given to molecules therefore increasing the number of collisions per second
the particles gain more energy and move faster. This means that they collide more often. If the temperature is decreased, the particles have less energy, move more slowly and collide less often

Question 15

what happens to the position of equilibrium when temperature increases

Answer 15

shifts to the endothermic side

Question 16

what happens to the position of equilibrium when temperature decreases

Answer 16

shifts to the exothermic side

Question 17

what happens to the position of equilibrium when we increase concentration

Answer 17

position shifts to the opposite side in which the concentration was increased to balance the equation again

Question 18

what happens to rate of reaction if we increase pressure

Answer 18

increases rate of reaction because there are more molecules per centimeter cubed therefore there are more collisions per second,
the number of particles in a given volume also increases an so the rate of reaction increases.

Question 19

what happens to the position of equilibrium once we increase pressure

Answer 19

shift to the side with less molecules

Question 20

what happens to the position of equilibirum if a catalyst is added

Answer 20

forawrd and backward reaction are sped up however there is no effect on position

Question 21

what is the symbol equation for the production of ammonia in the haber process

Answer 21

N2(g) +3H2(g) <–>2NH3(g)

Question 22

what are the sources of hydrogen and nitrogen in the Haber process

Answer 22

hydrogen- methane
nitrogen- air

Question 23

what are the typical conditions in the Haber process

Answer 23

450 celsius
20000kPa/200 atm
iron catalyst

Question 24

what is the symbol equation for the conversion of sulfur dioxide into sulfur trioxide in contact process

Answer 24

2SO2(g) + O2(g) <—> 2SO3(g)

Question 25

what are the sources of sulfur dioxide and oxygen in contact process

Answer 25

sulfur dioxide- burning sulfur or roasting sulfide ores
oxygen- air

Question 26

what are the typical conditions for the conversion of sulfur dioxide to sulfur trioxide int he contact process

Answer 26

450 celsius
200kPa/2atm
vanadium oxide catalyst

Question 27

what is used as fertilisers

Answer 27

ammonium salts
nitrates

Question 28

what is the use of NPK fertilisers

Answer 28

to provide the elements nitrogen phosphorus and potassium for improved plant growth

Question 29

what happens to rate of reaction when you add a catalyst

Answer 29

increases, the rate of reaction in both forward and backward directions by providing an alternate pathway with lower activation energy

Question 30

what happens to rate of reaction when you increase concentration

Answer 30

the rate of reaction increases the frequency of collisions between reactants and will, therefore, increase the reaction rate, increased chance in succesful collisions

Question 31

describe collision theory in terms of number of particles per unit volume

Answer 31

bigger number of particles more collisions
and vice versa

Question 32

describe collision theory in terms of changing pressure of gas

Answer 32

bigger pressure of gas means greater number of collisions

Question 33

describe collision theory in terms of kinetic energy of particles

Answer 33

greater kinetic energy means more collisions, because particles move faster therefore more collisions per sec

Question 34

describe collision theory in terms of activation energy

Answer 34

every reaction to start, the molecules need an activation energy so that there are collisions. there must be sufficiently energetic collisions t break chemical bonds

Question 35

what is the effect on rate of reaction by changing surface area of solids

Answer 35

When solids react, the reaction occurs on the surface of the substance. If there is more surface area exposed, then this will increase the rate of reaction. You can increase the surface area by making the size of the particles smaller.

Question 36

what happens to rate of reaction by adding or removing a catalyst, including enzymes using collisions theory

Answer 36

A catalyst is a substance that speeds up the rate of a reaction but it does not get used up in the reaction. As a catalyst does not get used up in the reaction, they can be reused or recycled.
enzymes, which are biological catalysts. They increase the rate of biochemical reactions – for example, respiration in our bodies. They work best at an optimum pH and temperature. If the temperature is too high or if pH is too extreme, enzymes can lose their structure and be denatured (destroyed). Once an enzyme is denatured, it will not work anymore

Question 37

what do catalysts do to activation energy

Answer 37

they decrease it

Question 38

what are practical methods for the investigation of rate of reaction

Answer 38

to show how concentration changes the rate of reaction, you can conduct an experiment in which you change the concentration or mass used of a reactant and measure the time it takes for a colour change to happen, or measure the amount of gas produced with a syringe to be more precise.

Question 39

what is the name of the process that produces ammonia

Answer 39

haber process

Question 40

what is the name of the process that produces sulfuric acid

Answer 40

contact process

Question 41

describe the contact process

Answer 41

sulfur is turned into sulfur dioxide by burning in air (exo)
then sulfur dioxide is turned into sulfur trioxide by mixing it with more air and passed over beds ov vanadium oxide catalyst
thent sulfur trioxide is dissolved in concentrated sulfuric acid to turn into a thick fuming liquid called oleum (h2s207)
and lastly oleum is added to water and turns into concentrated sulfuric acid