CC11 Flashcards
What is the reactivity series?
A list of metals in order of reactivity with the most reactive at the top.
How does potassium and sodium react with water and dilute acid?
Water - React with cold water to form hydrogen and a metal hydroxide
Dilute acid - React violently
How does calcium react with water and dilute acid?
Water- React with cold water to form hydrogen and a metal hydroxide
Dilute acid - React to form a hydrogen and a salt solution
How does magnesium, aluminium, zinc and iron react with water and dilute acid?
Water - React very slowly, if at all, with cold water but react with steam to form hydrogen and a metal oxide
Dilute acid - React to form hydrogen and a salt solution
How does copper, silver and gold react with water and dilute acid?
Water - Do not react with cold water or steam
Dilute acid - Do not react
What do the metals that react with cold water form?
Hydrogen and a metal hydroxide solution(e.g. 2K(s) + 2H₂O(l) –> 2KOH(aq) + H₂(g)
What do metals that react with steam form?
Hydrogen and a solid metal oxide (e.g. 2Mg(s) + H₂O(g) –> 2MgO(s) + H₂(g)
What do metals that react with dilute acids form?
Hydrogen and a salt solution (e.g. Zn(s) + H₂SO₄(aq) –> ZnSO₄(aq) + H₂(g)
How does the ease of a metal losing electrons correlate with its position in the reactivity series?
The more easily a metal’s atoms lose electrons, the higher the metal is in the reactivity series.
What is a displacement reaction?
A displacement reaction occurs when a more reactive element displaces, or pushes out, a less reactive element from a compound that contains the less reactive element.
How does a displacement reaction work (use the example of zinc dipped in copper sulfate solution)?
When zinc is dipped into copper sulfate solution, a copper coating forms on the surface of the zinc. Some of the zinc takes the place of the copper and forms zinc sulfate solution (Zn(S) + CuSO₄(aq) –> Cu + ZnSO₄(aq)) Zinc replaces copper as it is more reactive than it.
What is a redox reaction?
A reaction in which both oxidation and reduction occurs.
What state are very unreactive metals naturally found in?
Very unreactive metals, such as gold and platinum, are found naturally in their native state (as uncombined elements).
What state are very reactive metals naturally found in?
Quite reactive metals have reacted with other elements to form compounds in rocks.
What is extraction?
The process of obtaining a metal from compounds.
What is an ore?
An ore is a rock that contains enough of a compound to extract a metal for profit.
What displacement reaction occurs with iron oxide and carbon?
Carbon is more reactive than iron, so it displaces it (Iron oxide + Carbon –> Iron + Carbon oxide)
What does the ore Heamatite contain?
Iron Oxide.
What does the ore Malachite contain?
Copper Carbonate.
What method of extraction must be used for Potassium, Sodium, Calcium, Magnesium and Aluminium?
Electrolysis of a molten compound.
What method of extraction must be used for Zinc, Iron and Copper?
Heat an ore with carbon.
What method of extraction must be used for Silver and Gold?
Found as the uncombined element.
What is Bioleaching and how does it work?
Bioleaching uses bacteria grown on a low grade ore. The bacteria produces a solution containing copper ions, called a leachate. Copper is extracted from the leachate by displacement using scrap iron, then purified by electrolysis. This method can also be used for metals such as nickel, cobalt and zinc.
What is Phytoextraction and how does it work?
Phytoextraction involves growing plants that absorb metal compounds. The plants are burnt to form ash, from which metal is extracted.
What are the advantages and disadvantages of Bioleaching?
Advantages: - Doesn’t require high temperatures
Disadvantages: - Toxic substances and sulfuric acid can be produced by the process, and damage the environment
What are the advantages and disadvantages of Phytoextraction?
Advantages: - Can extract metals from contaminated solids
Disadvantages: - More expensive than mining some ores
- Growing plants is dependent on weather conditions
How is metal extracted from metal oxide ores?
In order to obtain the metal from metal oxide ores, the oxygen must be removed. This is known as reduction
What is reduction (in terms of oxygen)?
Reduction is the loss of oxygen from a substance.
What is oxidation (in terms of oxygen)?
Oxidation is the gain of oxygen by a substance.
What are redox reactions?
A reaction where both oxidation and reduction occurs.
What is corrosion?
When a metal reacts with oxygen, making the metal weaker over time. The metal becomes oxidised (gains oxygen).
How does the reactivity of a metal affect the rate of corrosion?
The more reactive a metal is, the more rapidly it corrodes.
What is a tarnish?
A protected oxide layer that prevents further corrosion. This covers metal surfaces.
How can metals be recycled?
By melting them down and making them into something new.
What are some advantages to recycling?
- Less waste metal ends up in landfill sites
- Less pollution may be produced
- The need to mine ores is reduced (mining can damage the landscape and create noise and dust pollution)
What are some disadvantages to recycling?
- The cost of recycling
- The amount of energy used when recycling
What is a Life Cycle Assessment?
An assessment that can be carried out to work out the environmental impact of a product.
What does LCA stand for?
Life Cycle Assessment.
What is a Life cycle assessment used for?
- They are used to decide wether it is worthwhile to manufacture and recycle a product.
- They are used to compare the effect of using different materials for the same product (e.g. making a bottle out of glass or plastic)
What are the four stages looked at in a Life cycle assessment?
- Obtaining and processing raw materials
- Manufacturing and packaging the product
- Using the product
- Disposal of the product
What are the questions to ask when making a Life cycle assessment?
- What raw materials are needed?
- How are the raw materials processed?
- How much energy is needed for the manufacture and packaging of the product?
- Where will the energy come from?
- What will the product be used for?
- How will the product be disposed of?
