paper 2

Question 1

how can u increase rate of reaction (collision theory)

Answer 1

-increasing the frequency of collisions
-increasing energy of the particles when they collide

Question 2

how will increasing temperature affect the rate of reaction
(by heating)

Answer 2

increases rate of reaction as:
1.particles move fatser (more frequent collisions)
2.particles have more energy (more successful collisions)

Question 3

how will increasing concentration (of solutions) affect rate of reaction
(by using solution with more solute for same volume of solvent)

Answer 3

increases rate
as more reactant particles in reacion mixture
so higher frequency of collisions

Question 4

how will increasing pressure (of gases) affect rate of reaction
(by increasing number of gas particles you have in container/making container smaller)

Answer 4

increased rate of reaction
less space between particles means more frequent collisions

Question 5

how will increasing the surface area (of solids) affect the rate of reaction
(by cutting solid into smaller pieces/powder)

Answer 5

increases rate of reaction
as the greater the surface area, the more reactant particles that are exposed
leading to more frequent collisions

Question 6

define closed system

Answer 6

no reactants or products can escape (eventually reaches dynamic equilibrium)

Question 7

at dynamic equilibrium..

Answer 7

the rates or products turning into reactants and reactants turning into products are equal so overall amount of reactants and products are equal

Question 8

list 3 ways of changing reaction conditions to shift equilibrium

Answer 8

1.change conc of substances
2. change temp of entire reaction vessel
3. changing pressure inside vessel

Question 9

what is Le Châtelier’s principle

Answer 9

if conditions of closed system are changed, closed system wikk then counteract changes by favouring either the forward or reverse reaction

Question 10

effect on equlibrium if conc of product is decreased

Answer 10

favours forward reaction

Question 11

effect on equlibrium if conc of product is increased

Answer 11

favours reverse reaction

Question 12

effect on equilibrium if conc of reactant is decreased

Answer 12

favours reverse reaction

Question 13

effect on equilibrium if conc of reactant is increased

Answer 13

favours forward reaction

Question 14

effect on equilibrium if temp of surroundings increases

Answer 14

favours endothermic reaction

Question 15

effect on equilibrium if temp of surroundings decreases

Answer 15

favours exothermic reaction

Question 16

effect on equilibrium if you increase pressure

Answer 16

favours reaction that results in fewer moles

Question 17

effect of equilibrium if you decrease pressure

Answer 17

favours reaction that results in more moles

Question 18

3 properties of hydrocarbons
what length of chain are they highest

Answer 18

flammability, (how easily it burns) high: short chain
boiling point, (temp it boils) high: long
viscositty (how thick it is) high: long (very thick)

Question 19

list first 4 alkanes

Answer 19

methane, ethane, propane, butane

Question 20

guve 6 steps of fractional distillation

Answer 20

1. crude oil is vapourised
2. hydrocarbon gases enter fractionating column
3. hydrocarbons rise up column due to temperature gradient
4. as hydrocarbon gases rise up column they cool down
5. when different hcs reach their boiling point, they condense
6. hydrocarbon fractions collected

Question 21

what is left at the bottom of fractionating colum

Answer 21

residue
very thick, sticky mixture of long chain hydrocarbons
used in making roads and flat roofs

Question 22

give the 3 products of fractional distillation

Answer 22

1. fuels
   e.g petrol, diesel oil, kerosene, heavy fuel oil, liquified petroleum gases
2. feedstock
   fractions form raw material for other processes and the production of other substances
3. useful materials produced
   e.g. solvents, lubricants, polymers and detergents

Question 23

define cracking

Answer 23

used to break up longer hydrocarbons and turn into shorter ones
produces shorter alkanes and alkenes

Question 24

describe the 2 methods of cracking

Answer 24

catalytic cracking-
vaporise hydrocarbons, pass over a hot catalyst

steam cracking-
mix hydrocarbons with steam at a very high temp

Question 25

define a pure substance

Answer 25

substance that contains a single element and boil at a specific temperature not a range of temperatures

Question 26

define formulations

Answer 26

mixtures designed in specific quantities for a specific purpose

Question 27

list examples of formulations

Answer 27

fuels, cleaning agents, paints, alloys, fertilisers, foods

Question 28

Rf value

Answer 28

always less than 1 distance moved by substance / distance moved by solvent

Question 29

what does chromatography do

Answer 29

separates different components in a mixture

Question 30

stationary phase of chromatography

Answer 30

paper

Question 31

mobile phase of chromatography

Answer 31

solvent

Question 32

test for hydrogen and positive result

Answer 32

lit splint speaking pop

Question 33

test for oxygen and positive result

Answer 33

glowing splint relights

Question 34

test for co2 and positive result

Answer 34

bubble through limewater turns cloudy

Question 35

test for chlorine and positive result

Answer 35

hold piece of damp litmus paper near gas bleaches white

Question 36

define flame emission spectroscopy

Answer 36

type of intrumental analysis similar to flame test sample solution put into flame and light given off is passed through a spectroscope, instrument tells you exactly which wavelength of light is being given off as a line spectrum compare spectrum to rference to establish identity of sample

Question 37

define instrumental analysis

Answer 37

using complex scientific equipment to test substances they are rapid and accurate also sensistuve so can give results even with very small amounts of substance