Topic 5 - Separate Chemistry 1

Where on the periodic table are transition metals

between groups two and 3

properties of transition metals

high melting points, high densities, stronger and harder than the metals in group 1 and 2. form coloured compounds and can be used as catalysts

how to prevent rusting of iron

exclusion of oxygen and water (painting, oil) or sacrificial protection (in contact with a more reactive metal that will react first

electroplating

thin layer of an unreactive metal is deposited on the surface of iron to keep air and water out

why does converting metals into alloys make them stronger

different size atoms disrupt the layers in the lattices structure meaning the atoms cannot slide over each other

magnalium

aluminium and magnesium for its low density for airplanes

jewlery gold

gold and copper for its resistance to corrosion

brass

copper and zinc which is a good electrical conductor

titration practical

Use a beaker and funnel to put dilute HCL into the burette

Use the pipette and pipette filler to add sodium hydroxide and indicator

Put the flask on a white tile underneath the burette

Record the burette start reading

Add acid to the alkali  until the end point

Record the burette end reading

Continue until concordant results

percentage yield

actual yield/theorectical yield x 100

why is actual yield ususally less

incomplete reactions, side reactions and practical losses

atom economy

total mr of desired product/ total mr of all products

Haber Process

reversible reaction used to make ammonia from nitrogen and hydrogen

why is the temperature a compromise in the Haber process

a lower temperature would increase yield, but a higher temperature increase rate

NPK fertilisers

nitrogen, phosphourous, potassium. supplied for plant roots to absorb

ammonia and nitric acid

ammonium nitrate which is good for soils

chemical cell

produces a voltage until one of the reactants is used up

fuel cell

hydrogen and oxygen are the only reactants, so water vapour is the only product

chemical cells vs fuel cells

chemical cells are cheaper and suitable for portable appliances however can be harmful and go flat. Hydrogen-oxygen cells produce water as waste and do not go flat, however are not portable and very expensive