AQA Chemistry 8462 - Using Resources Vocabulary Flashcards

Vocabulary flashcards covering section 4.10 of AQA Chemistry 8462: Using Resources, potable water, wastewater, LCAs, materials, alloys, corrosion, and NPK fertilisers.

Natural resource

A material or substance that occurs naturally and can be used by humans.

Examples of natural resources

Water, timber, metal ores, crude oil, natural gas and agricultural materials.

Finite resource

A resource that is used faster than it is naturally replaced and can eventually run out.

Renewable resource

A resource that is naturally replenished at a rate comparable with its use.

Examples of finite resources

Metal ores and fossil fuels such as crude oil, coal and natural gas.

Examples of renewable resources

Timber and crops when they are managed sustainably.

Sustainable development

Meeting the needs of current generations without compromising the ability of future generations to meet their needs.

Importance of chemistry in sustainable development

Chemistry can help reduce resource use, develop alternatives, recycle materials and reduce environmental impacts.

Factors when choosing a material or process

Raw materials, energy, waste, environmental impact, cost and performance.

Potable water

Water that is safe to drink.

Potable water purity requirement

It does not have to be chemically pure $H_2O$; it can contain low levels of dissolved substances but must be safe to drink.

Characteristics of potable water

Safe levels of microbes and dissolved substances, with acceptable taste and appearance.

Source of most UK potable water

Fresh water sources such as reservoirs, lakes, rivers and groundwater.

Fresh water treatment for potability

Choosing a suitable source, filtering it and sterilising it.

Filtration in water treatment

Removes insoluble solid particles.

Sterilisation methods for drinking water

Using chlorine, ozone or ultraviolet light.

Purpose of sterilisation in water treatment

To kill harmful microorganisms.

Need for desalination

Required where fresh water supplies are limited but seawater or salty water is available.

Desalination

Removing dissolved salts from seawater or other salty water to produce potable water.

Desalination methods

Distillation and reverse osmosis.

Reason desalination is expensive

It requires large amounts of energy.

Required Practical 8 subject

Analysis and purification of water samples from different sources.

Required Practical 8 pre-purification measurements

pH and dissolved-solids measurements, such as mass after evaporation.

Obtaining pure water in Required Practical 8

By distillation.

Role of distillation in water purification

Water is evaporated and condensed, leaving many dissolved solids behind.

Wastewater

Water that has been used and contains contaminants.

Sources of wastewater

Domestic sewage, agricultural systems and industrial processes.

Purpose of wastewater treatment

To remove harmful materials before water is released or reused.

Stages of sewage treatment

Screening and grit removal, sedimentation, biological treatment of effluent and anaerobic digestion of sludge.

Screening in sewage treatment

Removal of large objects and debris.

Sedimentation in sewage treatment

Suspended solids settle out as sludge.

Biological treatment of sewage effluent

Aerobic microorganisms break down organic matter.

Sewage sludge treatment

It can be anaerobically digested by microorganisms.

Useful product of anaerobic digestion

Biogas, containing methane.

Specialised treatment of industrial wastewater

Necessary because it may contain particular toxic chemicals, metals or other contaminants.

Potable water from wastewater vs. fresh water treatment

Wastewater treatment usually needs more treatment and energy because more contaminants must be removed.

Phytomining

Using plants to absorb metal compounds from low-grade ores; the plants are harvested and processed to obtain the metal.

Usefulness of phytomining

It can extract metals from low-grade ores where traditional mining may be uneconomic.

Bioleaching

Using bacteria to produce solutions containing metal compounds from low-grade ores.

Extracting copper after bioleaching

Copper can be extracted from the solution by displacement with a more reactive metal or by electrolysis.

Disadvantage of biological metal-extraction methods

They are often slow.

Advantage of biological metal-extraction methods

They can reduce traditional mining and use low-grade ores.

Importance of recycling metals

It conserves finite ores and often uses less energy than extracting metals from ores.

Life cycle assessment (LCA)

An assessment of the environmental impacts of a product throughout its life.

Four broad stages of an LCA

Extracting and processing raw materials, manufacturing and packaging, use, and disposal or recycling.

Environmental factors in an LCA

Energy and resource use, emissions, pollution, waste and transport.

Subjectivity in LCA comparisons

Different people may give different importance to different environmental impacts.

Manipulation of LCAs

Selected data or chosen weightings can make one product appear more favourable.

Evaluating an LCA claim

Check the evidence, assumptions, boundaries of the assessment and which impacts were included or omitted.

Recycling

Processing used materials so they can be used again.

Environmental benefits of product reuse

Avoids or delays the need to manufacture a replacement and reduces waste.

Energy reduction through recycling

Producing a material from recycled feedstock can require less energy than extracting and processing new raw materials.

Disadvantages of recycling

Collection, sorting and processing require energy and money, and some materials lose quality.

Whole life cycle comparison rationale

An option that looks better at one stage may have greater impacts at another stage.

Corrosion

The destruction of materials by chemical reactions with substances in the environment.

Rusting

The corrosion of iron.

Requirements for iron to rust

Oxygen and water.

Barrier method for preventing rusting

Coating the iron with paint, grease, plastic or another barrier that keeps out oxygen and water.

Galvanising

Coating iron or steel with zinc.

Zinc protection of scratched galvanised coating

Zinc is more reactive and is oxidised in preference to iron, providing sacrificial protection.

Sacrificial protection

Using a more reactive metal that corrodes instead of the protected metal.

Aluminium corrosion resistance

Forms a thin, adherent aluminium oxide layer that protects the metal underneath.

Alloy

A mixture of a metal with one or more other elements.

Purpose of making alloys

To produce materials with improved or tailored properties.

Bronze

An alloy of copper and tin.

Brass

An alloy of copper and zinc.

Gold alloys

Gold combined with other metals such as silver, copper and zinc to make it harder.

Steel

An alloy based on iron with carbon and sometimes other elements.

Low-carbon steel vs. high-carbon steel

Low-carbon steel is softer and easier to shape; high-carbon steel is harder and stronger but more brittle.

Stainless steel corrosion resistance

It contains chromium, which helps form a protective oxide layer.

Aluminium alloys properties

Valued for low density combined with useful strength.

Borosilicate glass

Glass made using sand and boron trioxide, with a higher melting point than soda-lime glass.

Raw materials for soda-lime glass

Sand, sodium carbonate and limestone.

Clay ceramics production

Clay is shaped and then heated strongly in a furnace.

Composite material

A material made by combining two or more materials with different properties.

Two main parts of a composite

A matrix or binder surrounding and binding a reinforcement.

Usefulness of composites

The combination can give properties that the individual materials do not have alone.

Examples of composites

Fibreglass, carbon-fibre composites and reinforced concrete.

Factors in material selection

Required properties, cost, durability, environmental impact and intended use.

Three essential elements in fertilisers

Nitrogen, phosphorus and potassium.

NPK

Nitrogen, phosphorus and potassium.

Purpose of NPK fertilisers

To replace mineral ions needed for healthy plant growth.

Raw materials for ammonia manufacture

Nitrogen and hydrogen.

Haber process

The industrial process used to make ammonia.

Making ammonium salts from ammonia

By reacting ammonia with acids.

Acid used to make ammonium nitrate

Nitric acid (reacts with ammonia).

Acid used to make ammonium sulfate

Sulfuric acid (reacts with ammonia).

Obtaining phosphate rock

By mining.

Chemical treatment of phosphate rock

To make phosphate compounds more soluble and available to plants.

Obtaining potassium compounds for fertilisers

By mining potassium-containing salts.

Industrial fertiliser processes vs. laboratory preparations

Industry must optimise yield, rate, energy use, cost, safety and continuous large-scale production.

Central sustainability idea in Using Resources

Use materials and energy efficiently, minimise waste and environmental harm, and conserve resources for the future.