Using resources (paper 2)

What is potable water?

What is potable water?

Water you can drink

Why isn’t potable water classified as pure?

• Pure water only contains water molecules

• Potable water contains other dissolved substances

What’s fresh water?

Water that doesn’t have much dissolved in it, but still contains some dissolved substances

suggest how copper sulphate can be used as a test for the presence of water

1. add water to anhydrous copper sulfate

2. colour should change from white to blue if water is present

What’s the process of fresh water/ground water sources being treated to be safe to drink?

1. Filtration- wire mesh screens out large twigs

2. gravel and sand beds filter out any other solid bits

3. Sterilisation- water is sterilised to kill harmful bacteria or microbes by adding chlorine gas through it (ozone or UV light can be used as well)

What does desalination do?

Brings levels of dissolved minerals down to have an acceptable level for potable water

What does reverse osmosis do?

• Reduce the levels of dissolved minerals

• Requires large amounts of energy so can be expensive

Define finite and give examples

• A limited resource that can’t be replaced

• Eg. Coal, gas, metal ores, limestone

Where do natural resources come from?

1. Earth

2. Sea

3. Air

What do we use resources for?

• warmth

• Shelter

• Food

• Transport

• They are produced by farming (eg. Cotton, trees = fuels)

Define renewable and give examples

• a resource that can be replaced

• Eg. Crops to make biofuel, wood

Describe the factors that make estimating how long finite resources will last difficult

• recycling may allow resource to become available

• There may be new resources that are discovered

What are the risks of extracting finite resources?

Provides jobs and brings money, but mining is bad for the environment, uses energy, scars landscapes, destroys habitats and produces waste

What’s a synthetic alternative?

• Replacement for natural resources

• Eg. Rubber (use of crude oil instead of tree sap)

Many materials used in the modern world are?

Limited

What’s sustainable development?

meets needs of current generation without compromising needs for future generations

Unsustainable

Not all resources are renewable so it’s unsustainable to keep using them

Why can extracting be unsustainable?

• the amount of energy used

• The waste produced

What ways can we reduce the use of finite resources?

• use them less

• Chemists can develop and adapt processes that use lower amounts of finite resources = can reduce damage to environment

• Eg. Catalysts, they reduce the amount of energy required for certain industrial processes

How do we improve coppers sustainability?

• By extracting it from low grade ores (ores without much copper inside)

• reduce damage to environment

• Process is slow

What’s positive about recycling metals?

• Use less energy to extract

• Conserves finite amount

• Cuts down waste sent to landfills

How are metals recycled?

• melted

• Casted into shape of new product

What’s a blast furnace used for?

Used to extract iron from its ore at a high temperature using carbon

What does waste water treatment ensure?

• we don’t pollute the natural environment

• We can access nice clean water

Why must water go through waste water treatment?

• may contain organic matter (faeces)

• May contain harmful chemicals

Define biological aerobic digestion

Air is pumped through the water, encouraging aerobic bacteria to break down any organic matter (including microbes)

What’s the process for treating waste water at sewage treatment plants?

1. Screening- removes large bits (twigs/plastic bags) as well as grit

2. Sedimentation- heavier solids sink to bottom in a settlement tank to produce sludge, lighter effluent floats to the top (liquid waste)

3. Effluent is removed and treated by biological aerobic digestion

4. Sludge from bottom is removed and transferred into large tanks, its broken down by anaerobic digestion releasing methane gas which can be used as an energy source

5. Remaining waste can be used for fertiliser

Why is obtaining potable water from salty water more expensive than taking it from ground water?

• Distillation requires fuel (to boil water)

• Ground water only needs filtering and sterilising

Describe how nitrous dioxide is produced in the engine of a car that burns fossil fuels

1. High temperatures in engine

2. Nitrogen reacts with oxygen

3. Produces nitrogen dioxide

Define what a life cycle assessment is?

asses the 4 stages of a products life to calculate environmental costs

What are the 4 main stages of a life cycle assessment?

1. extracting raw material

2. making and packaging product

3. use of produce

4. disposal of product

what do LCA’s allow us to do?

compare the environmental impact of different products

why are paper bags more harmful than plastic?

• they require more energy to manufacture

• their life span is shorter

What do we call LCAs that choose to ignore certain environmental impacts of a product?

selective LCA’s

what are the difficulties associated with LCA’s?

• subjective elements

• missing details

What does agricultural waste require the removal of?

Bacteria/microbes

What does industrial waste water require the removal of?

Chemicals

Give 2 problems that oxides of nitrogen cause

1. Acid rain

2. respiratory problems