Chemistry Flashcards
describe diamond
- each carbon make 4 covalent bonds
- used in cutting tools and jewelry
describe graphite
- each carbon makes 3 bonds
- arranged in layers which can slide
- one electron from each atom is delocalised so is good conductor
alkali metal + water —
metal hydroxide + hydrogen
alkali metal + oxygen —
metal oxide
state the use for argon
filament lamps
state use for helium
floating balloons
airships
what is a metal ore ?
rock with enough metal to make it economically viable to extract
what are the 3 ways to extract a metal from its ore ?
- reduction with carbon
- electrolysis
- displacement reaction
how are metals extracted by reduction with carbon ?
react with carbon (smelt), oxygen will bond with the carbon
only works with less reactive metals than carbon
why is copper extracted by reduction not used for electrical wiring ?
this method makes impure copper, reducing the conductivity
how does electrolysis work ?
- compound dissolved in water conducts (electrolyte)
- ions go to the electrodes and gain / lose electrons to become atoms
what is the negative electrode called ?
cathode (gives electrons)
what is the positive electrode called ?
anode (accepts electrons)
when is electrolysis used ?
- high profits (expensive process)
- metal is more reactive than carbon
describe the properties / uses of copper
- good conductors so electrical wires
- hard but can be bent
- can’t react with water (less reactive than hydrogen)
describe the properties / uses of aluminium
- corrosion-resistant and low density
- forms hard alloys
- used in planes
describe the properties / uses of titanium
- corrosion-resistant, low density, very strong
- replacement hips
why are alloys generally harder ?
different sized atoms make it harder to slide past each other
what is crude oil ?
a mixture of hydrocarbons
what is an electrophile ?
electron pair acceptor
what is a nucleophile ?
electron pair donor
what is the most common example of electrophilic addition ?
alkene and bromine
orange bromine water to colourless
how do you name a polymer ?
poly (monomer name)
what is nomenclature ?
naming organic compounds
what is the ‘dripping’ equipment used in titration called ?
burette
what does volatile mean ?
easily evaporated
what is a monoprotic acid?
gives one H+ per molecules when dissociates (hydrochloric acid)
what is a diprotic acid?
gives two H+ (sulfuric acid)
what is a triprotic acid?
gives 3 H+ (phosphoric acid)
what is the relationship between conductivity and weak/strong acids ?
the stronger the acid, the more conductive it is due to increased conc of ions
give the method for making insoluble salts
- mix two soluble salts
- filter, wash, dry
give the method for making soluble salt from insoluble base and acid
- react until all acid has been neutralised
- filter, crystalise salt
give method for making soluble salt from soluble base (alkali) and acid
- neutralise acid by titration
- warm salt solution to get crystals
metal + acid —
salt + hydrogen
what is a disproportionate reaction ?
element is both oxidised and reduced in same reaction
what is the equation for iron rusting ?
Iron + oxygen + water — hydrated iron(|||) oxide
name 5 ways to prevent iron from rusting
- make alloys
- oiling/greasing/painting
- galvanise (coated in thin layer of zinc)
- sacrificial protection (covered by more reactive metal)
Q =
mc delta T
what is the specific heat capacity of water ?
4.2
bond breaking is an … process
exothermic
bond making is an … process
endothermic
what does Haber process make ?
ammonia from nitrogen and hydrogen
where is the nitrogen and hydrogen (used in Haber process) from ?
nitrogen - fractional distillation of liquid air
hydrogen - natural gas
what are the conditions for Haber process ?
iron catalyst
200 atm
450C
give the flame test method
- dip a wire in HCl and rinse with distilled water
- dip in sample and put in blue flame
whats the test for chlorine ?
will bleach damp litmus paper
what is the test for halides ?
add silver nitrate, will form a coloured precipitate
what is the test for sulfates ?
add barium chloride, will form white precipitate
Rf =
distance by compound / distance by solvent
what is an electrolyte ?
liquid that contains ions and can conduct electricity
how is methanol dangerous ?
toxic + can cause blindness if consumed
how is ethanol dangerous ?
can cause damage to liver and brain
are alcohols miscible ?
small carbon chains are, solubility decreases as chain length increases
what is formed when alcohols react with sodium ?
hydrogen and alkoxides
state the uses of ethanol
- solvent (perfumes)
- fuel (spirit burners)
- ## can be mixed with petrol
Ethanol + oxygen —
ethanoic acid + water
ethanoic acid + sodium carbonate —
sodium ethanoate + water + CO2
what is electroplating ?
process of coating a metal with another using electrolysis
for electroplating, what are the anode, cathode and electrolyte ?
anode - the outer metal
cathode - the inner metal
electrolyte - outer metal salt solution
what is a separating funnel used for ?
separating immiscible liquids
what is fractional distillation ?
separating a liquid mixture into different parts (fractions) due to difference in boiling points
what is soft water ?
water that contains no calcium/magnesium ions
what is difference between permanently and temporarily hard water ?
Mg and Ca ions can be removed from temporarily by boiling
state two ways of changing hard water to soft
- add washing soda (sodium carbonate)
- pass through ion exchange column
what is a hydrogen fuel cell ?
hydrogen reacts with oxygen (without burning) to produce water - energy is released from reaction
