P1C11 - Obtaining + using metals Flashcards
What’s an example of an oxidation reaction?
When metals react with oxygen, metal oxides are produced:
Magnesium + oxygen → magnesium oxide
2Mg + O2 → 2MgO
What’s an example of a reduction reaction?
When metal oxides lose oxygen and return to their atomic form:
Iron oxide + carbon monoxide → iron + carbon dioxide
Fe2O3 + 3CO → 2Fe + 3CO2
Whats 2 examples of highly unreactive metals?
Gold and Platinum
(Also known as crust metals)
What are the only metals that don’t react with dilute acids?
copper, silver, gold and platinum.
What are the metals that react with dilute acid but not cold water?
magnesium, aluminium, zinc, iron and lead (iron and lead react slowly).
Why is carbon used to extract metals?
- If metal is lower than carbon in reactivity, that metal will be extracted.
- Carbon is cheap and abundant
How is carbon used to extract metals?
In the reduction, the metal oxide loses oxygen to form a pure metal.
Reduction involves heating the metal oxide with the carbon, which is often used in the form of coal.
How is bioleaching used to extract copper?
- Bacteria are added in with low-grade ores.
- The bacteria break down the ores to create a solution rich in copper compounds known as a leachate solution.
- We can easily extract copper from leachate solution.
- Slow
How is phytomining used to extract copper?
- Plants growing on contaminated land absorb copper ions as they grow.
- These plants are harvested and burned, producing ash that contains high concentrations of copper compounds.
Why is recycling a benefit?
Conserves finite resources
Reduced burning of fossil fuels
Less energy required
Fewer waste rock heaps
What are the steps in the process of recycling metals?
- Melt
- Reshape
What is Life cycle assessment?
The assessment of all four stages of a product’s life cycle to try and calculate its total environmental costs.
What are the four stages of Life cycle assessment? LCAS
Collecting raw materials
Making and packaging product
Product use
Disposal of product
