C3 Flashcards
what rocks are formed when volcanic lava solidifies?
igneous
what are 3 important raw materials?
.coal
.salt
.limestone
what are the stages of forming limestone?
.shellfish died forming sediments on the sea bed
.sediments compacted and hardened
.tectonic plates push it upwards to surface
.rock are eroded away until late limestone shows through
what climate was coal formed in?
wet swampy conditions when plants trees and furniture died and became buried
why is rock salt spread on icy roads?
.the rock is insoluble but the sand in the rock gives grip
.it shows up so people know the roads have been gritted
.the salt in solution lowers the freezing point preventing ice from forming easily
how can pure salt be obtained?
by solution mining with is mainly automatic
what can mining rock and solution be bad and what is done to prevent it?
.subsidence
.they leave about half the salt rock there
how can salt be contaminated?
while mining it can allow water in mines which may let salt Leach out into water supplies contaminating them
what does a higher salt level prevent?
bacteria growth
what organisation is responsible for carrying out risk assessments for chemicals in food and advertising the public about how how food affects health?
.the government department of health
.the government department of the environment food and Rural affairs
when acids and alkalis neutralise what do they make?
salt
what is lime used for?
.neutralising acidic soils
.making glass when heated with sand removing empuritys when iron is made
what is the word equation for neutralisation?
acid+alkali-> salt + water
what is alum? and how is it purified
.a mordant that sticks to dye a fabric
.reacting it with ammonia contained in stale urine
who discovered how to manufacture alkalis?
Nicholas lablanc in 1978
how did the lablanc process make sodium carbonate?
by reacting salt and limestone, heated with coal
what did the lablanc presses give off?
large amounts of hydrogen chloride, along with solid waste including galligu that slowly released hydrogen sulfide and a foul smelling toxic gas
what was the harmful hydrogen chloride changed into?
.chlorine used to breach textiles prior to duying
.hydrocloric acid which is a starting material for making other chemicals
how can chlorine be made?
by reacting hydrocloric acid and manganese dioxide
what does oxidation do to hydrogen chloride?
turns it into chlorine
what are alkalis? name some examples?
.soluable metal hydroxide and solvable metal carbonates
.soluable hydroxides- sodium hydroxide, calcium hydroxides, potassium hydroxide
.soluable carbonates- sodium carbonate, potassium carbonate
what are bases? and what do they react with?
are metal hydroxide and metal carbonates that are insoluable. they react with acids in a similar way to alkalis but do not affect indicators
what did chlorination prevent?
water born microorganisms such as cholera and typhoid
what happens when chlorine reacts with organic materials in water supplies?
it forms toxic or carcinogenic compounds called disinfectant by-product (DBS)
what does electrolysis do?
breaks up compounds using an electric current
what does the electrolysis of brine make?
chlorine gas
hydrogen gas
sodium hydroxide solution
what is the negative and positive electrode called during electrolysis?
.anode+
.cathode-
what is one way to electrolysis brine continuously?
membrane cell method
during brine electrolysis what forms at the anode and cathode?
annode- chlorine
cathode- hydrogen
what are some industrial uses of chlorine and hydrogen and sodium hydroxide?
.chlorine makes plastics
.hydrogen for making margarine
.sodium hydroxide- for paper recycling
what do the products of brine do to the environment?
.chlorine products from fridges and are obsolescence are linked to ozone depletion so have been banned
.chlorine during paper bleaching releases dangerous dioxins, increasing risk of cancer
.plastics made using chlorine are non biodegradable
what do chemicals contain?
elements. they cannot be destroyed so they remin in the environment forever
what happens if pvc is burnt?
it gives off toxic gasses including dioxins
if eaten these chemicals could build up in fat and cause cancer
what do we need to consider at each stage of an LAC?
.how much natural resource are required
.how much energy is produced
.how much water and air is used
.how the environment is affected
what aspects are hard to measure when taking a life cycle assessment?
disposal method can vary Same with everything else
