unit 3

Question 1

what happens if the reaction rate is too low?

Answer 1

process will not be economically viable

Question 2

what happens if the reaction rate is too high?

Answer 2

there will be an explosion

Question 3

what is required for a successful collision?

Answer 3

energy above or equal to the activation energy

correct collision geometry

Question 4

what forms when atoms have a successful collision?

Answer 4

an activated complex

Question 5

what is an activated complex?

Answer 5

unstable arrangement of atoms

Question 6

how does particle size increase the rate of reaction?

Answer 6

decrease particle size increases surface area
larger area for collisions to occur on

Question 7

how does concentration increase the rate of reaction?

Answer 7

increase concentration
more particles moving around so more collisions occurring

Question 8

how does temperature increase the rate of reaction?

Answer 8

increase temperature
particles have a higher level of energy
more particles have energy above or equal to the activation energy

Question 9

how does pressure increase the rate of reaction?

Answer 9

pressure increases
particles are pushed together

Question 10

how do catalysts increase the rate of reaction?

Answer 10

offers a different pathway with a lower activation energy

Question 11

what is the activation energy?

Answer 11

minimum energy required by colliding particles to form an
activated complex

Question 12

enthalpy change exothermic
pos/neg

Answer 12

negative

Question 13

enthalpy change endothermic
pos/neg

Answer 13

positive

Question 14

enthalpy representation in an equation

Answer 14

deltaH

Question 15

why is the atom economy 100%?

Answer 15

only one product is formed

Question 16

how are industrial processes designed?

Answer 16

to maximize products
to minimize environmental impact

Question 17

factors influencing industrial design

Answer 17

sustainability
cost
recycle
energy
availability
marketability
yield

Question 18

what is feedstock?

Answer 18

a reactant which goes into a chemical process, usually extracted from raw materials

Question 19

what are raw materials?

Answer 19

natural resources the earth supplies us

Question 20

what are environmental considerations?

Answer 20

minimising waste
avoiding the use or production of toxic substances
designing products which will biodegrade if possible

Question 21

what is enthalpy?

Answer 21

a measure of the chemical energy in a substance

Question 22

exothermic reactions in industry

Answer 22

releases heat energy
may require heat to be removed to prevent the temperature rising

Question 22

endothermic reactions in industry

Answer 22

takes in heat energy
costs increased by supplying heat energy in order to maintain the reaction rate

Question 23

what is the enthalpy of combustion?

Answer 23

one mole of the substance burns completely in oxygen

Question 24

when changing the fuel, what variable are you keeping the same?

Answer 24

distance between flame and copper can
mass of water
windshields
thermometer positioning

Question 25

why are your results lower than the EOC standard results?

Answer 25

heat lost to surroundings
incomplete combustion of alcohol
mass loss due to evaporation of alcohol

Question 26

why are bomb calorimeter used?

Answer 26

no energy is lost as the vessel is sealed (all energy is transferred to the water)
it allows for complete combustion

Question 27

what is bond enthalpy?

Answer 27

energy required to break one mole of bonds in a diatomic molecule

Question 28

what is mean bond enthalpy?

Answer 28

average energy required to break one mole of bonds for a bond that occurs in a number of compounds

Question 29

why is bond breaking positive?

Answer 29

energy has to be put in
- endothermic

Question 30

rules for dynamic equilibrium

Answer 30

1. rate of the forward reaction is equal to the rate of the reverse reaction
2. the concentration of reactants and products remains constant
3. the concentrations are not usually equal
4. the reaction has not stopped

Question 31

how does a reaction achieve equilibria

Answer 31

has to be a closed system

Question 32

effect of a catalyst on equilibrium

Answer 32

no effect on the position of equilibrium
allow equilibrium to be reached more quickly or established at a lower temper (makes reactions more profitable)

Question 33

what is chromotography?

Answer 33

technique used to separate the components present within a mixture

Question 34

how does chromatography separate substances?

Answer 34

making use of differences in their polarity (solubility) or molecular size (smaller the molecule, the further they travel)

Question 35

how can you identify a component through chromatography?

Answer 35

the distance it has travelled or the time it has taken to travel through the apparatus (retention time)

Question 36

what is used to show the end point of a titration?

Answer 36

an indicator

Question 37

what is a standard solution?

Answer 37

a solution of accurately known concentration

Question 38

why does a redox titration using acidified permanganate does not require an indicator?

Answer 38

the solution turns colourless when reduced

Question 39

what solution does not require an indicator during a redox titration?

Answer 39

acidified permanganate solution

Question 40

process of making a standard solution

Answer 40

dissolve substance in water
transfer solution and rinsings to a volumetric flask
fill volumetric flask up to the line with water

Question 41

describe process of using burette in a titration

Answer 41

rinse out burette with solution going in it
fill it to above the scale
drain some of the acid and read from the bottom of the meniscus

Question 42

if an indicator is not clear enough, what do you use to show the end point in a titration?

Answer 42

white tile below conical flask