Reactivity & Redox Flashcards
What is an oxidising agent?
The chemical that causes erosion
Wha is the reducing agent?
The chemical that causes the other chemical to be reduced
What is the word equation for rust?
Iron + oxygen + water -> hydrated iron (III) oxide
What are the two main ways of preventing rusting?
Barrier methods and sacrificial method
Give two examples of barrier methods
- Painting/Coaitng with plastic
2. Oiling/ Greasing
Give two examples of sacrificial protection
- Coating the object in zinc - galvanising
2. Attaching a zinc block to the iron
What are the three raw materials involved in the blast furnace?
Iron ore, Coke, limestone
What is the equation for when calcium oxide reacts with the sand to form slag?
CaO + SiO2 -> CaSiO3
Give a use for slag
Road building or fetiliser
Acid + metal -> ?
Salt + hydrogen
What is the process used for extraction of aluminium?
Electrolysis
What is the ore that aluminium is extracted from called?
Bauxite
Why is molten cryolite used?
To lower the temperature and to lower the cost
How is molten cryolite used?
Aluminium oxide is dissolved in molten cryolite. This brings the temperature down to 900*c which makes it much cheaper and easier.
Describe how electrolysis is used to extract aluminium
The positive Al3+ ions are attracted to the cathode where they pick up electrons an they turn into aluminium atoms and sink to the bottom. The negative O2- ions are attracted to the anode where they lose electrons. The oxygen atoms then react with each other to form 02 or with the carbon anode to form CO2
