Topic 5 - Separate Chemistry 1 Flashcards
Transition metals are the metals in
The middle of the periodic table, most of the metals
Transition metals properties
Hard, strong, shiny and malleable
Good heat and electricity conductors
High melting point
High density
They form coloured compounds
Good catalysts(such as iron for the haber process)
The oxidation of metals results in
Corrosion
Rusting of iron is a
Redox reaction
Metals corrode in the presence of
Oxygen and water to form their metal oxides
Rusting is
the corrosion of iron
Ways to prevent rusting
Exclusion of oxygen
Exclusion of water
Sacrificial protection
Sacrificial protection is when
Another mroe reactive metal is put with the iron, so that this reacts with the oxygen and water rather than the iron
Electroplating is
Using electrolysis to coat teh surface of a metal with another metal
Electroplating is used to
Improve the appearance of a metal
Protect against corrosion
Alloys are
Metals combined with another metal or non-metal
Pure metals are malleabel because
they have a regular arrangement of atoms so the layers can slide over eachother
Alloys are stronger than pure metals because
The atoms are different sizes, so the arrangement becomes random. This means the layers cant slide
Iron is alloyed with carbon
steels`
Steels are
Stronger and less corrosive than iron
Gold alloys are used for
Jewllery because it is stronger than pure gold
Aluminium alloys are used for
Making aircraft because it is light and strong
Copper+tin=
Bronze which is harder than copper
Copper+zinc=
Brass which is more malleabel than bronze
Magnalium=
Aluminium+Magnesium
Magnalium with low magnesium is
Strong, light and resistant to corrosion
Magnalium with high magnsium content is
More stable than pure magnesium but still reactive enough to make fireworks
Concentration is measured in
mol dm-3 or g dm-3
Concentration(mol dm-3) =
Number of moles / Volume of solution(dm3)
To convert mol dm-3 to g dm-3
Mulitply it by the relative formula mass of the solute
To convert g dm-3 to mol dm-3
Divide it by relative formula mass
Titrations are used to
Find out exactly how much acid is needed to neutralise a given quantity of alkali(or vice versa)
titration steps
Use pipette to measure set volume of alkali into flask
Add a few drops of phenolphthaline indicator
Fill a biurette with a known concentration of acid
Slowly open biurette into flask until there is a colour change from pink to clear
Record amount of acid used to neutralise
Use this to calculate conc.
Percentage yield compares
the amount of product you should get vs how much product you actually get
Percentage yield =
Actual yield/ Theoretical yield x100
Percentage yield isnt 100% because of
Incomplete reactions
Practical losses
Unwanted reactions
Atom economy is
The % of reactants chnaged to useful products
Atom economy =
Total Mr of desired products / Total Mr of all products x100
Factors considered when doing chemical reactions in industry
Atom economy
Percentage yield
Rate of reaction
Equilibrium position
Molar volume is
the volume occupied by one mole of gas
Molar volume(dm3 mol-1) =
Gas volume / Number of moles
Avogadoros law states (gases)
Under the same conditions, the same number of moles of different gases occupy the same volume
One mole of any gas always occupies
24dm3 at room temperature and pressure(20*C and 1 atmsophere)
Volume of gas(dm3) =
Moles x 24
The haber process is
a reversible reaction between nitrogen and hydrogen to form ammonia
Change in temp on equilibrium
Decrease - Move in exothermic direction
Increase - Move in endothermic direction
Chnage in pressure on equilibrium
Decrease - Move towards side with more moles of gas
Increase - Towards side with less moles of gas
Change in concentration on equilibrium
Increase reactants - Equilibrium moves right
Increase products - Equilibrium move left
And vice versa
Catalyst on equilibrium
Increases the speed that a reaction reaches equilibrium
Haber process industrial factors considered
The cost of materials
Energy costs
Changing conditions to produce a good yield in a good time
3 main elements of fertilisers
Nitrogen, phosphorus, potassium
Fertilisers contain NPK to
Provide these elements to the soil so that plants are rich in them. Then the plants will gorw better and die less
Ammonia fertilisers are made by
Reacting ammonia with nitric acid to produce a nitrogen-containing salt.
Different methods of preparing ammonium sulfate
Laboratory preparation
Industrial production
Laboratory preparation of ammonium sulfate
Use ammonia and dilute sulfuric acid in a titration
Industrial production of ammonium sulfate
No titration because it takes too long
Ammonia from haber process
Large scale
Fuel cells use
Fuel and oxygen to produce electrical energy
Chemical cells produce a
Voltage across the cell until one reactant has been used up
Hydrogen-oxygen fuel cells use
Hydrogen as a fuel. The reaction of hydrogen and oxygen releases energy. The only product is water
Advantages of fuel cells
Efficient
Electricity produced directly from the reaction
No energy lost through friction
No pollutants produced
Disadvantages of fuel cells
Hydrogen gas takes up lots of space
Very explosive
Hydrogen is often made using electricity from fossil fuels
