questions ive got wrong

Question 1

whats the difference between a base and an alakli

Answer 1

BASES- react with acids by accepting H+ ions to form salts

ALKALIS- soluble bases which release OH- ions in aq solutions

Question 2

state le chatelier prinipal

Answer 2

the position of equilibrium will shift to minimise the change in conditions

Question 3

what happens when pressure increases

Answer 3

If the pressure is increased, the position of equilibrium moves in the direction of the fewest moles of gas

Question 4

what happens when pressure decreases

Answer 4

If the pressure is decreased, the position of equilibrium moves in the direction of more moles of gas

Question 5

how to calculate percentage error?

Answer 5

uncertainty (times the amount of measurements taken)/ difference between readings (the measurement)x100

Question 6

how do u produce an alcohol from an alkene

Answer 6

steam hydration (using h20) with acid catalyst

Question 7

when identifying the organic product, what is it asking for?

Answer 7

the full name of the thing produced

Question 8

how to add alcohol and carboxylic acid together to make a ester

Answer 8

??

Question 9

Suggest why CF2Cl

2 does not hydrolyse in water

Answer 9

C-F and C=Cl bonds need a large amount of energy to break

Question 10

Why are scientists concerned about ozone depletion?

Answer 10

more UV= increased risk of skin cancer

Question 11

International agreements have reduced the use of CFCs. However the concentration of
atmospheric CFCs has hardly changed.
Suggest two reasons why.

Answer 11

• CFCs have a long lifetime

- CFCs are still entering the atmosphere.

Question 12

when calculating enthalpy change of combustion for 2AlS3, what do u need to make sure that u do

Answer 12

divide by 2

Question 13

what do u call it when a molecule has a double bond and two bond pairs when referring to shape

Answer 13

it has 3 bonding regions- 2 bonded pairs and 2 double bond

Question 14

why are c, o2 and cl2 all classified as p-block elements

Answer 14

their highest energy electrons are in the p-orbital

Question 15

how to obtain a salt after reacting a solid metal and aq acid together

Answer 15

• filter it to obtain precipitate

- evaporate it

Question 16

x axis of Boltzmann

Answer 16

energy

Question 17

y axis of Boltzmann

Answer 17

amount of particles

Question 18

whats an example of a general equation for free radical sub?

Answer 18

C5H12 +3CI2 —> C5H9CI3 + 3HCI

Question 19

acid + heat from alcohol=

Answer 19

alkene

Question 20

when doing mechanism for nucleophillic sub, where does the halogen atom needs to be

Answer 20

needs to be on an area thats considered primary

Question 21

what structure does Cl have

Answer 21

a simple covalent lattice

Question 22

what are the elements arranged in

Answer 22

increasing atomic number

Question 23

At room temperature and pressure, the first four members of the alkanes are all gases but the
first four alcohols are all liquids.
Explain this difference in terms of intermolecular forces

Answer 23

alcohols have hydrogen bonds and induced dipole- dipole interactions, hydrogen bonds are stronger than induced dipole-dipole interactions.

Question 24

what is the reaction called when alcohols go to alkenes

Answer 24

elimination/dehydration

Question 25

What is meant by the term average bond enthalpy?

Answer 25

the avg enthalpy change when 1 mol of bonds of gaseous covalent bonds are broken

Question 26

when describing the Boltzmann curve with a catalyst, what do u ahve to say

Answer 26

- a catalyst lowers activation energy by providing an alternate route.

Question 27

State an example of a catalyst used by the chemical industry and write the equation for the reaction that is catalysed.

Answer 27

catalyst; nickel catalyst ( hydrogenation of alkene) | equation: C2H4 + H2 --> C2H6

Question 28

state 3 things that are correct for dynamic equilibrium

Answer 28

- equilibrium can be achieved from both sides - the rate of the forwards reaction is equal to the rate of the reverse - the system is closed

Question 29

whats one advantage of using polymers from food

Answer 29

- they are biodegradable | - photodegradable

Question 30

what are aliphatic molecules

Answer 30

c and h joined in a straight chain, branched chain but have non aromatic rings

Question 31

what are alicyclic molecules

Answer 31

in a ring, can be saturated a little but not aromatic

Question 32

when testing for bromine water what happens to the bonds

Answer 32

the c=c bond breaks and electrophilic addition of bromine takes place onto the molecule

Question 33

whats a mole

Answer 33

the amount of any substance containing as many particles as there are carbon atoms in exactly 12g of the carbon-12 isotope

Question 34

what type of mechanism is likely to produce a mixture of organic products and why

Answer 34

free radical substitution because substitution can replace any H atom

Question 35

when identifying an element, what subatomic particle do u identify it with

Answer 35

electrons

Question 36

when using titrations, how any decimal places should it be to

Answer 36

2

Question 37

describe why at has the highest bp in the halogens

Answer 37

- has the most electrons so produces the largest instantaneous dipole which causes neighbouring molecules to have a greater attraction towards it thus there are stronger INTERMOLECULAR FORCES BETWEEN MOLECULES and it takes more energy to break these

Question 38

when calculating Kc, how do u calculate it

Answer 38

products/ reactants

Question 39

what do unsaturated molecules contain

Answer 39

a c=c double bond

Question 40

whats an electrophile

Answer 40

an electron pair acceptor

Question 41

why does radical substitution produce a mixture of organic products

Answer 41

- more than 1 termination step - substitution can happen at different places along the chain - further substitution can occur

Question 42

whats the M+ peak

Answer 42

The positive ion formed in mass spectrometry when a molecule loses an electron

Question 43

What is the M+1 peak?

Answer 43

A very small peak to the right of the M+ peak caused by the Carbon 13 isotope. It occurs mostly in larger, organic compounds.

Question 44

what are titres within

Answer 44

0.1 cm^3 of each other

Question 45

why is the first ionisation energy not followed for Mg and Al

Answer 45

Mg electron is removed from the 3s and Al electron is removed from 3p. The outer Al electron has a higher energy

Question 46

whats an everyday use of IR spec

Answer 46

breath analysers | -monitoring pollution

Question 47

whats a biodegradable alternative to CFCs

Answer 47

hydrocarbons or HFCs