questions ive got wrong Flashcards
whats the difference between a base and an alakli
BASES- react with acids by accepting H+ ions to form salts
ALKALIS- soluble bases which release OH- ions in aq solutions
state le chatelier prinipal
the position of equilibrium will shift to minimise the change in conditions
what happens when pressure increases
If the pressure is increased, the position of equilibrium moves in the direction of the fewest moles of gas
what happens when pressure decreases
If the pressure is decreased, the position of equilibrium moves in the direction of more moles of gas
how to calculate percentage error?
uncertainty (times the amount of measurements taken)/ difference between readings (the measurement)x100
how do u produce an alcohol from an alkene
steam hydration (using h20) with acid catalyst
when identifying the organic product, what is it asking for?
the full name of the thing produced
how to add alcohol and carboxylic acid together to make a ester
??
Suggest why CF2Cl
2 does not hydrolyse in water
C-F and C=Cl bonds need a large amount of energy to break
Why are scientists concerned about ozone depletion?
more UV= increased risk of skin cancer
International agreements have reduced the use of CFCs. However the concentration of
atmospheric CFCs has hardly changed.
Suggest two reasons why.
- CFCs have a long lifetime
- CFCs are still entering the atmosphere.
when calculating enthalpy change of combustion for 2AlS3, what do u need to make sure that u do
divide by 2
what do u call it when a molecule has a double bond and two bond pairs when referring to shape
it has 3 bonding regions- 2 bonded pairs and 2 double bond
why are c, o2 and cl2 all classified as p-block elements
their highest energy electrons are in the p-orbital
how to obtain a salt after reacting a solid metal and aq acid together
- filter it to obtain precipitate
- evaporate it
x axis of Boltzmann
energy
y axis of Boltzmann
amount of particles
whats an example of a general equation for free radical sub?
C5H12 +3CI2 —> C5H9CI3 + 3HCI
acid + heat from alcohol=
alkene
when doing mechanism for nucleophillic sub, where does the halogen atom needs to be
needs to be on an area thats considered primary
what structure does Cl have
a simple covalent lattice
what are the elements arranged in
increasing atomic number
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
alcohols have hydrogen bonds and induced dipole- dipole interactions, hydrogen bonds are stronger than induced dipole-dipole interactions.
what is the reaction called when alcohols go to alkenes
elimination/dehydration
What is meant by the term average bond enthalpy?
the avg enthalpy change when 1 mol of bonds of gaseous covalent bonds are broken
when describing the Boltzmann curve with a catalyst, what do u ahve to say
- a catalyst lowers activation energy by providing an alternate route.
State an example of a catalyst used by the chemical industry and write the equation for
the reaction that is catalysed.
catalyst; nickel catalyst ( hydrogenation of alkene)
equation: C2H4 + H2 –> C2H6
state 3 things that are correct for dynamic equilibrium
- 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
whats one advantage of using polymers from food
- they are biodegradable
- photodegradable
what are aliphatic molecules
c and h joined in a straight chain, branched chain but have non aromatic rings
what are alicyclic molecules
in a ring, can be saturated a little but not aromatic
when testing for bromine water what happens to the bonds
the c=c bond breaks and electrophilic addition of bromine takes place onto the molecule
whats a mole
the amount of any substance containing as many particles as there are carbon atoms in exactly 12g of the carbon-12 isotope
what type of mechanism is likely to produce a mixture of organic products and why
free radical substitution because substitution can replace any H atom
when identifying an element, what subatomic particle do u identify it with
electrons
when using titrations, how any decimal places should it be to
2
describe why at has the highest bp in the halogens
- 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
when calculating Kc, how do u calculate it
products/ reactants
what do unsaturated molecules contain
a c=c double bond
whats an electrophile
an electron pair acceptor
why does radical substitution produce a mixture of organic products
- more than 1 termination step
- substitution can happen at different places along the chain
- further substitution can occur
whats the M+ peak
The positive ion formed in mass spectrometry when a molecule loses an electron
What is the M+1 peak?
A very small peak to the right of the M+ peak caused by the Carbon 13 isotope. It occurs mostly in larger, organic compounds.
what are titres within
0.1 cm^3 of each other
why is the first ionisation energy not followed for Mg and Al
Mg electron is removed from the 3s and Al electron is removed from 3p.
The outer Al electron has a higher energy
whats an everyday use of IR spec
breath analysers
-monitoring pollution
whats a biodegradable alternative to CFCs
hydrocarbons or HFCs
