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questions ive got wrong Flashcards

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1
Q

whats the difference between a base and an alakli

A

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

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

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2
Q

state le chatelier prinipal

A

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

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3
Q

what happens when pressure increases

A

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

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4
Q

what happens when pressure decreases

A

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

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5
Q

how to calculate percentage error?

A

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

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6
Q

how do u produce an alcohol from an alkene

A

steam hydration (using h20) with acid catalyst

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7
Q

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

A

the full name of the thing produced

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8
Q

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

A

??

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9
Q

Suggest why CF2Cl

2 does not hydrolyse in water

A

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

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10
Q

Why are scientists concerned about ozone depletion?

A

more UV= increased risk of skin cancer

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11
Q

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

A
  • CFCs have a long lifetime

- CFCs are still entering the atmosphere.

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12
Q

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

A

divide by 2

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13
Q

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

A

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

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14
Q

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

A

their highest energy electrons are in the p-orbital

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15
Q

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

A
  • filter it to obtain precipitate

- evaporate it

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16
Q

x axis of Boltzmann

A

energy

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17
Q

y axis of Boltzmann

A

amount of particles

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18
Q

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

A

C5H12 +3CI2 —> C5H9CI3 + 3HCI

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19
Q

acid + heat from alcohol=

A

alkene

20
Q

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

A

needs to be on an area thats considered primary

21
Q

what structure does Cl have

A

a simple covalent lattice

22
Q

what are the elements arranged in

A

increasing atomic number

23
Q

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

A

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

24
Q

what is the reaction called when alcohols go to alkenes

A

elimination/dehydration

25
Q

What is meant by the term average bond enthalpy?

A

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

26
Q

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

A
  • a catalyst lowers activation energy by providing an alternate route.
27
Q

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

A

catalyst; nickel catalyst ( hydrogenation of alkene)

equation: C2H4 + H2 –> C2H6

28
Q

state 3 things that are correct for dynamic equilibrium

A
  • 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
29
Q

whats one advantage of using polymers from food

A
  • they are biodegradable

- photodegradable

30
Q

what are aliphatic molecules

A

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

31
Q

what are alicyclic molecules

A

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

32
Q

when testing for bromine water what happens to the bonds

A

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

33
Q

whats a mole

A

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

34
Q

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

A

free radical substitution because substitution can replace any H atom

35
Q

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

A

electrons

36
Q

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

A

2

37
Q

describe why at has the highest bp in the halogens

A
  • 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
38
Q

when calculating Kc, how do u calculate it

A

products/ reactants

39
Q

what do unsaturated molecules contain

A

a c=c double bond

40
Q

whats an electrophile

A

an electron pair acceptor

41
Q

why does radical substitution produce a mixture of organic products

A
  • more than 1 termination step
  • substitution can happen at different places along the chain
  • further substitution can occur
42
Q

whats the M+ peak

A

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

43
Q

What is the M+1 peak?

A

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

44
Q

what are titres within

A

0.1 cm^3 of each other

45
Q

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

A

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

46
Q

whats an everyday use of IR spec

A

breath analysers

-monitoring pollution

47
Q

whats a biodegradable alternative to CFCs

A

hydrocarbons or HFCs

chem (14 decks)

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