C5 & C6

Question 1

What is corrosion?

Answer 1

Corrosion is the gradual destruction of metals due to reactions with oxygen and water, such as rusting in iron.

Question 2

What is an alloy?

Answer 2

An alloy is a mixture of a metal with one or more other elements, designed to improve its properties.

Question 3

What is the main ore of copper, and how is it extracted?

Answer 3

The main ore is malachite, and copper is extracted by heating it with carbon, as it is below carbon in the reactivity series.

Question 4

What is the main ore of iron, and how is it extracted?

Answer 4

The main ore is haematite, and iron is extracted using a blast furnace where carbon reduces iron oxide to iron.

Question 5

How is aluminium extracted, and what is its ore?

Answer 5

Aluminium is extracted by electrolysis of molten aluminium oxide (from its ore bauxite).

Question 6

What is bioleaching?

Answer 6

Bioleaching uses bacteria to extract metals from low-grade ores by producing solutions containing metal ions.

Question 7

What is phytomining?

Answer 7

Phytomining uses plants to absorb metals from soil. The plants are burned, and the ash contains metal compounds.

Question 8

What are the main methods to prevent or reduce corrosion?

Answer 8

Applying a physical barrier, such as paint or oil.

Using a sacrificial metal that reacts instead of the protected metal (e.g., zinc coating).

Question 9

What are life cycle assessments (LCAs)?

Answer 9

LCAs evaluate the environmental impact of a product over its life, from raw materials to disposal.

Question 10

What are the four stages of a life cycle assessment?

Answer 10

1. Extraction and processing of raw materials.
2. Manufacturing and packaging.
3. Use and operation.
4. Disposal or recycling.

Question 11

How is crude oil formed?

Answer 11

Crude oil is formed from the remains of ancient marine organisms compressed under heat and pressure over millions of years.

Question 12

What is the fractionating column used for?

Answer 12

The fractionating column separates crude oil into fractions based on boiling points, such as petrol, diesel, and kerosene.

Question 13

What is atom economy?

Answer 13

Atom economy measures the efficiency of a reaction by comparing the mass of desired products to the total mass of products.

Question 13

What is the equation for atom economy?

Answer 13

AtomEconomy= Mr of desired products / Mr of all products x 100

Question 14

What is percentage yield?

Answer 14

Percentage yield compares the actual amount of product obtained to the theoretical maximum amount predicted.

Question 15

What is the equation for percentage yield?

Answer 15

PercentageYield= Actual Yield
————————— x 100
TheoreticalYield

Question 16

What is titration used for?

Answer 16

Titration is used to determine the concentration of an unknown solution by reacting it with a solution of known concentration.

Question 17

What indicator is commonly used in acid-base titrations?

Answer 17

Phenolphthalein or methyl orange, depending on the reactants.

Question 18

How do you perform a titration?

Answer 18

1. Fill a burette with the known solution.
2. Add the unknown solution to a flask with a few drops of indicator.
3. Slowly add the known solution until the indicator changes colour.
4. Record the volume used to calculate the unknown concentration.

Question 19

What is meant by Dynamic Equilibrium?

Answer 19

When the rate of the forwards reaction happens at the same rate of the backwards reaction.

And the concentration of the reactants and products do not change.