Topic 10 - Using Resources

What are Ceramics? How are they made? What are some Examples/Uses?

Ceramics are non-metal solids with high melting points that aren’t made from carbon-based compounds.

It is moulded it into the wanted shape. It is then fired at high temperatures to harden it.

Clay - Pottery and Bricks

Glass - Soda-Lime Glass and Borosilicate Glass

What are Composites and how are they made?

A material made of one or more materials embedded in another with properties different to the individual components.

They are made with fibres or fragments of a material which are reinforcements and with a binding material called a matrix.

What are some examples of Composites and their uses?

Fibre Glass - M Polymer - R Glass Fibres - U Skis, Boats and Surfboards

Natural Wood - M Lignin - R Cellulose Fibres - U Fencing, Doors and Flooring

MDF and Plywood - M Adhesives - R Wood Fibres - U Furniture, Flooring and Shelving

Carbon Fibre Composites - M Polymer - R Carbon Fibres - U Aerospace and Car Manufacturing

Concrete - M Cement/Water - R Sand/Gravel - U Building Materials

What are some examples of Alloys and their Uses?

Bronze - Copper + Tin - It is harder than copper - Medals, Statues and Ornaments

Brass - Copper + Zinc - More Malleable than Bronze - Hinges, Pipes and Instruments

Steel - Iron + Carbon - Low Carbon is Malleable - Car Bodies - High Carbon is strong/brittle - Bridges

Stainless Steel - Iron + Chromium + Nickel - Corrosion-resistant and durable - Cutlery, Medical Instruments, and Kitchen Appliances

What is Corrosion?

The process of metals being gradually destroyed by reacting substances in the environment.

What is Rust and the Formula?

The process where iron corrodes.

Iron + Oxygen + Water → Hydrated Iron(III) Oxide

It only happens on the surface of a material as oxygen and water are both required.

It causes the iron to flake off revealing more iron over time.

How can you prevent Rusting?

Painting - applying a protective layer to keep moisture and oxygen away from the metal surface

Electroplating - coating the metal with a layer of another metal using electrolysis

Oiling - Applying oil to create a barrier against moisture and oxygen for moving parts

Sacrificing - Using a more reactive metal that corrodes first, protecting the iron from rusting

Galvanisation - Using zinc to protect iron and then be sacrificed

How is Copper extracted from Low-Grade Ores?

Bioleaching - A process that uses bacteria to covert copper compounds into soluble copper ions, which can then be recovered through electrolysis or displacement.

Phytomining - Growing plants in soil that contains copper. The plants can’t use it so it slowly builds up in the leaves. The plant is then harvested, dried and burnt. The ash contains soluble copper compounds that can be extracted by electrolysis or displacement.

What is the Life Cycle Assessment?

It is an assessment of the impact a product has on the environment throughout it’s life.

It involves evaluating the stages from raw material extraction to disposal, including manufacturing, use, and recycling.

What is Potable Water and some sources for Water?

Water that is safe for drinking and cooking, free from harmful contaminants.

Types include Sea Water, Groundwater, Fresh Water, Waste Water, Potable Water and Pure Water.

How is Water Treated?

Fresh Water:

Filtration - A wire mesh screens out larger materials, gravel and sand beds filter out smaller bits

Sterilisation - The water is sterilised to kill and harmful bacteria or microbes by bubbling chlorine gas through it or using ultraviolet light

Sea Water:

Reverse Osmosis - It removes salts and other impurities from seawater by pushing it through a semipermeable membrane that only allows water molecules through

Distillation - Heating seawater to remove soluble salts and impurities

Describe how you can use Distillation to desalinate sea water (RP)?

• Start by testing the pH (Using Litmus Paper to not contaminate it) of the water to ensure it is suitable for distillation, otherwise you can use titration to neutralise it.

• You should also test it for Sodium Chloride. Flame test for Sodium ions (Yellow) and for Chloride ions take a sample and add nitric acid and silver nitrate (White Precipitate).

• To distil the water use a Bunsen burner to boil the water in a conical flask with a bung and tube leading to a test tube in a beaker of ice.

• The boiled water will form steam which condense back into a liquid from the cold test tube, leaving any dissolved salts in the flask.

• Retest the distilled water for pH and sodium chloride to check if the experiment worked.

What is Waste Water?

Water that has been used and contains impurities, making it unsuitable for drinking. It can come from households, industries, or sewage systems.

How is waste waster treated?

1. Screening - Large solids and grit are removed by a wire mesh.

2. Sedimentation - It is put in sedimentary tanks where the heavier suspended solids sink to the bottom producing sludge and lighter effluent floats to the top.

3. Aeration - The effluent is aerated to promote the growth of bacteria that break down organic matter.

4. Final Settling Tanks - Bacteria used before sinks to the bottom as sludge and the treated water is separated.

5. Anaerobic Digestion - The sludge is broken down by anaerobic bacteria to produce methane gas and waste.

6. Waste is used for fertilisers and methane gas is used for heat and electricity

What is the Haber Process?

A process used to make Ammonia by reacting nitrogen with hydrogen.

Nitrogen + Hydrogen → ← Ammonia (+ heat as endothermic)

N_{2 (g)} + 3H_{2 (g)} → ← 2NH_{3 (g)}

Describe how the Haber Process works?

Nitrogen is obtained from the air using fractional distillation of liquid air. Hydrogen is obtained from reacting methane with steam to form hydrogen and carbon dioxide.

The reactant gases are passed over an iron catalyst at a temperature of 450^oC and a pressure of 200 atmospheres.

As the reaction is reversible, some of the ammonia produced converts back to hydrogen and nitrogen again, until it eventually reaches dynamic equilibrium.

The ammonia gas cools in the condenser and it liquifies and is removed for use, while the unused hydrogen and nitrogen is recycled.

What happens to the yield if temperature and pressure changes?

As temperature increases, the the yield of ammonia decreases as the forward reaction is exothermic, so the equilibrium moves left towards the reactants. This leads to a lower temperature being ideal for the yield

However, as temperature decreases, so does the rate, resulting in a compromise of temperature at 450 for maximum yield and rate.

As pressure increases, the yield increases so the equilibrium moves right towards the products.

However, too high of a pressure leads to lots of energy being required making the process too expensive and dangerous to maintain. This leads to a compromise pressure of 200.

What are NPK Fertilisers?

A formulation providing nitrogen, phosphorus and potassium as nutrients to help plants to grow.

How are the elements gathered?

Potassium Chloride and Potassium Sulfate can be mined and used for potassium.

Phosphate rock can be mined, but it is insoluble in water, so plants can’t use them as nutrients.

Nitrogen can be obtained from the Haber Process or through the use of ammonium salts

Phosphorus and Nitrogen can be obtained from soluble phosphates: Nitric acid, Sulfuric acid and Phosphoric acid can react with phosphorus rock or ammonia.