Using Resources Questions P2

What is a finite resource?

A resource that will eventually run out (e.g., fossil fuels, metal ores).

What is a renewable resource?

A resource that can be replaced at the same rate it is used (e.g., timber, crops).

What is potable water?

Water that is safe to drink but not necessarily pure.

What are the key characteristics of potable water?

Low levels of dissolved salts and microbes.

How is potable water produced from fresh water in the UK?

Filtration to remove solids and sterilisation (with chlorine, ozone, or UV light) to kill microbes.

What is desalination?

The removal of salt from seawater to produce potable water.

What methods are used for desalination?

Distillation or reverse osmosis.

Why is desalination not commonly used in the UK?

It requires large amounts of energy and is expensive.

What are the steps in wastewater treatment?

Screening → sedimentation → aerobic and anaerobic digestion → discharge or further treatment.

What is screening?

Removing large solids and grit from wastewater.

What happens during sedimentation?

Solids settle to form sludge, and the liquid (effluent) remains on top.

How is effluent treated?

Using aerobic biological treatment to reduce bacteria and organic matter.

How is sludge treated?

By anaerobic digestion, producing methane for energy and fertiliser.

What is a life cycle assessment (LCA)?

A way of assessing the environmental impact of a product over its entire life.

What are the four stages of an LCA?

Raw material extraction

manufacture

use

disposal

What are some limitations of LCAs?

Some impacts (e.g. pollution, aesthetics) are difficult to quantify and may be subjective.

How can reuse help the environment?

It reduces the need for raw materials and lowers waste.

What is the difference between reuse and recycling?

Reuse keeps the original item/function; recycling breaks it down to make new products.

What are the environmental benefits of recycling metals?

It uses less energy, conserves resources, and reduces landfill and pollution.

What causes iron to rust?

Reaction with oxygen and water to form hydrated iron(III) oxide.

What is the word equation for rusting?

Iron + oxygen + water → hydrated iron(III) oxide

How can rusting be prevented?

Barrier methods (painting, oiling), galvanising, or sacrificial protection.

What is sacrificial protection?

Attaching a more reactive metal (e.g. zinc) to iron so it corrodes instead.

What is an alloy?

A mixture of a metal with other elements to improve properties.

Why are alloys harder than pure metals?

The different sized atoms distort the layers and prevent them from sliding.

What is bronze made from?

Copper and tin.

What is brass made from?

Copper and zinc.

What are gold alloys used for?

Jewellery – alloyed with silver, copper or zinc to increase hardness.

What is steel?

An alloy of iron and carbon.

What are the types of steel and their properties?

High carbon steel (hard but brittle)

low carbon steel (soft and easily shaped)

stainless steel (corrosion-resistant)

What are ceramics?

Non-metal solids with high melting points, e.g. glass and clay.

How is soda-lime glass made?

By heating a mixture of sand, sodium carbonate and limestone.

What is a composite?

A material made from two or more different materials with different properties.

Give examples of composites.

Fibreglass, carbon fibre, concrete, wood.

What are polymers?

Long chains of repeating units (monomers) joined together.

What determines a polymer’s properties?

The monomer type and the conditions used in polymerisation.

How are low density and high density poly(ethene) different?

LDPE is flexible (low pressure, high temp); HDPE is rigid (lower temp & catalyst).

What is the Haber process used for?

Making ammonia from nitrogen and hydrogen.

What is the word equation for the Haber process?

Nitrogen + hydrogen ⇌ ammonia

What are the conditions for the Haber process?

450°C, 200 atmospheres, iron catalyst.

Is the Haber process reversible?

Yes – it reaches a dynamic equilibrium.

Why is ammonia cooled and liquefied in the Haber process?

So it can be removed, shifting equilibrium to produce more.

Where is nitrogen sourced from for the Haber process?

The air (78% nitrogen).

Where is hydrogen sourced from for the Haber process?

Natural gas or from reacting methane with steam.

What is ammonia used for?

Making nitric acid, fertilisers and other chemicals.

What are NPK fertilisers?

Fertilisers containing nitrogen (N), phosphorus (P), and potassium (K).

What is the role of nitrogen in fertilisers?

Helps leafy growth and protein production.

What is the role of phosphorus in fertilisers?

Supports root growth and flower/fruit development.

What is the role of potassium in fertilisers?

Promotes overall plant health and disease resistance.

How is ammonium nitrate made in industry?

By reacting ammonia with nitric acid (exothermic reaction).

What is the required practical related to "Using Resources"?

Preparing a pure, dry sample of a soluble salt (e.g. copper sulfate) using crystallisation.

How do you make pure copper sulfate crystals?

React sulfuric acid with copper oxide, filter, heat the solution gently, then leave to crystallise.

What are the key steps in the salt crystallisation practical?

Add excess base, filter to remove unreacted base, heat solution, cool to crystallise.

What safety precautions are needed when handling acids and heating?

Wear goggles, use tongs for hot equipment, take care with Bunsen burner.