C6 ocr gcse

What method is used to extract a metal less reactive than carbon from its oxide?

Reduction with carbon (e.g., Fe{2}O{3} + 3C \rightarrow 2Fe + 3CO).

How are metals more reactive than carbon extracted?

By electrolysis of molten metal oxides (e.g., Al{2}O{3} \rightarrow Al + O_{2}).

Why can carbon reduce some metal oxides but not others?

Only metals below carbon in the reactivity series can be reduced by carbon.

What is corrosion?

The slow chemical reaction of a metal with oxygen and/or water, forming a compound like rust.

Name two ways to prevent corrosion.

Coating (paint, plastic), galvanising (zinc layer), and sacrificial protection.

What are the reactants in the Haber process?

Nitrogen (N{2}) and hydrogen (H{2}).

What is the purpose of the Haber process?

To produce ammonia (NH_{3}) for fertilisers.

Give the conditions used in the Haber process.

450^{\circ}C, 200\text{ atm}, and an iron catalyst.

What do NPK fertilisers provide?

Nitrogen (N) for leaves, Phosphorus (P) for roots, and Potassium (K) for flowers/fruit.

Give examples of compounds used for N, P, and K nutrients.

• N: ammonium nitrate\n- P: phosphate rock\n- K: potassium chloride

What is the main product of the Contact Process?

Sulfuric acid (H{2}SO{4}).

What is the key catalyst in the Contact Process?

Vanadium(V) oxide (V{2}O{5}).

State the main conditions used in the Contact Process.

450^{\circ}C, 2\text{ atm} pressure, and a V{2}O{5} catalyst.

What is a life cycle assessment (LCA)?

A method to assess the environmental impact of a product from raw material extraction through to disposal.

Name factors considered in a Life Cycle Assessment.

Energy use, pollution, waste, transport, and sustainability.

What is the difference between reuse and recycling?

• Reuse: Using the product again as it is.\n- Recycling: Processing materials to make a new product.

Give one environmental benefit of recycling.

Reduces landfill volume, conserves raw materials, and saves energy.

Give an example of a ceramic, composite, and polymer.

• Ceramic: pottery\n- Composite: fibreglass\n- Polymer: polyethylene

Why are composites often used in construction?

They combine the strengths of different materials, often being both strong and lightweight.

Name common properties of polymers.

They are typically flexible, insulating, and resistant to corrosion.

What is the general formula of alkanes?

C{n}H{2n+2}

Are alkanes saturated or unsaturated?

Saturated (they contain single bonds only).

What are the products of complete combustion of an alkane?

Carbon dioxide (CO{2}) and water (H{2}O).

What is the functional group of alcohols?

-OH (hydroxyl group).

Name a common alcohol and its formula.

Ethanol (C{2}H{5}OH).

What is the functional group of carboxylic acids?

-COOH

Give one property of carboxylic acids.

They are weak acids that react with carbonates to produce CO_{2}.

How are addition polymers formed?

By joining monomers with double bonds (alkenes) together without losing any atoms.

Give an example of an addition polymer.

Poly(ethene) or Poly(propene).

How are condensation polymers formed?

By monomers reacting together and losing a small molecule (usually water) with each linkage formed.

Give an example of a condensation polymer.

Polyester or Nylon.

How can you identify a condensation polymer from its structure?

Each linkage has a repeating functional group such as an ester (-COO-) or an amide (-CONH-).

Name three natural polymers.

Starch, cellulose, and proteins.

What is the function of cellulose in plants?

It provides structural support in cell walls.

What is fractional distillation used for in the context of hydrocarbons?

To separate a mixture of liquids with different boiling points, such as crude oil.

Why do different hydrocarbons separate in a fractionating column?

Because they have different boiling points based on their chain length.

What are hydrocarbons made of?

Hydrogen and carbon atoms only.

Name two types of hydrocarbons.

Alkanes and alkenes.

What is cracking?

The process of breaking long-chain hydrocarbons into shorter, more useful chains, often producing alkenes.

Why are alkenes useful?

They are reactive and serve as starting materials to make polymers.

Name one method of cracking.

Catalytic cracking or steam cracking.

What does a hydrogen fuel cell produce?

Electricity, water (H_{2}O), and heat.

Give an advantage of fuel cells over combustion engines.

They produce no greenhouse gas emissions at the point of use (only water).

What gas was most abundant in the Earth's early atmosphere?

Carbon dioxide (CO_{2}).

How did oxygen become abundant in the atmosphere?

Photosynthesis by plants and algae released O_{2}.

Name a human activity affecting atmospheric composition.

Burning fossil fuels, which increases the concentration of CO_{2}.

Name three greenhouse gases.

Carbon dioxide (CO{2}), methane (CH{4}), and water vapor (H_{2}O).

How do greenhouse gases cause global warming?

They trap heat (infrared radiation) within the Earth's atmosphere.

Name three common air pollutants.

Carbon monoxide (CO), sulfur dioxide (SO_{2}), and nitrogen oxides (NOx).

Name the three main stages of waste water treatment.

1. Screening & sedimentation\n2. Biological treatment\n3. Dis