Separate Chemistry 1 Flashcards
What are the properties of transition metals
hard
strong
shiny
malleable
good conductors
high boiling points (except mercury)
high densities
good catalysts
Examples of uses of transition metals
Gold is used in jewellery - shiny and malleable
Copper is used for water pipes - malleable and corrosion resistant (also used for electrical wiring as it is a good electrical conductor)
How do transition metal compounds look
Very colourful
What are alloys
A mixture of metals in an unfixed ratio
Why are alloys stronger
The differently sized particles prevent the layers from sliding over each other easily
Examples of uses of alloys
Steel - carbon + iron - less likely to rust
Brass - Copper + Zinc - more malleable used in water taps
Aluminium alloys - used in aircrafts
What kind of reaction is rusting of iron
Redox
Oxygen is reduced
Iron is oxidised
How to prevent rusting
Painting
Oiling
Greasing
Galvanising (Zinc)
What is electroplating
Applying a metal coating to an object
Use electrolysis
Object as cathode
What do titrations allow you to do
Find out exactly how much acid is required to neutralise a given quantity of alkali
How to calculate % yield
Actual yield / theoretical max yield (x 100)
Why do you almost never get 100% yield
Incomplete reactions
Unwanted side reactions
Practical losses
Energy lost to surroundings
What is atom economy
The % of reactants changed to useful products
How to calculate atom economy
Total Mr of desired product / Total Mr of all products (x100)
Why is high atom economy good
Less waste products
Less raw materials needed for a given amount of product
Why are the conditions for the Haber process used
High pressure is ideal but too high is to expensive
Lower temp. is ideal but would be a too slow rate of reaction
Catalyst used to make the reaction faster
Where are the gases for the Haber process obtained from
Nitrogen - Air
Hydrogen - crude oil or natural gas
What are the problems with using ammonia as a fertiliser
Can damage crops on it’s own
Toxic gas
Can evaporate away
However, when combined with other chemicals it can be used to supply nutrients (nitrogen, phosphorus and potassium)
How to calculate molar volume
gas volume / number of moles
What do fuel cells use to produce energy
Fuel and oxygen
What do hydrogen-oxygen fuel cells use as fuel
Hydrogen
Advantages of Hydrogen-Oxygen fuel cells
Very efficient
Less stages so less energy lost as heat and no moving parts so less energy lose through friction
No conventional pollutants
However
Hydrogen takes up more space to store
Hydrogen is highly explosive
The production of the fuel often involves fossil fuels
