C3 – Chemicals in Our Lives

C3 – Chemicals in Our Lives

Starter

• Element or Compound?

Sulphur

S

Carbon Dioxide

CO2

Water

H2O

Chlorine

Cl2

Sulphuric Acid

H2SO4

Carbon (Buckminsterfullerene)

C60

Sodium Hydroxide

NaOH

Definitions

• Element• Contains only one type of Atom.• Found on the Periodic Table (of elements)

• Compound• Consists of 2 or more elements bonded (fixed)

together

Which Elements are in the Compounds?

Carbon Dioxide

CO2

Water

H2O

Sulphuric Acid

H2SO4

Sodium Hydroxide

NaOH

Elements, Compounds and Rocks

• Rocks are a MIXTURE of Compounds

• The most common compound is Silicon Dioxide SiO2

• This is commonly known as Quartz or Silica

Rocks and Plate Movements

The Rock Cycle

Three Rock Types:

Sedimentary- made from sediment

Metamorphic– changed by heat and pressure

Igneous – formed from Lava or Magma (molten rock)

Plate Movements

Useful Resources from Rocks

• Coal (carbon)

• Limestone (Calcium Carbonate)

• Marble (Calcium Carbonate)

• Rock Salt (Sodium Chloride)

• Metal Ores (Compounds containing Metals)

Early Chemical Industry

What’s the use in Salt?

• What can Salt be used for?

• List as many things as you can.

• Hint – For some, Think about the elements that Salt is made from.

Uses of Salt

• Food (seasoning and preservation)

• Gritting Road (melts ice)

• Making Chlorine – Bleach

• Making Sodium Hydroxide – Soaps and Cleaners

• Making Hydrogen Gas – A Fuel

How is Salt obtained?

• Evaporation of Sea Water

• Mining of Rock salt

• Solution mining of Rock Salt

Why use salt in our food?

• Preservative (stops bacteria from growing)

• Flavour enhancer (seasoning)• Makes food taste better / stronger

Salted Cod – Used to Preserve it

What is Risk?

• Risk depends upon 2 factors:

• Chance of something happening

• Level of harm that occurs if it does

Risk

• Actual Risk – A Risk calculated from actual data

• Perceived Risk – A risk thought by individuals without clear data to support it

Precautionary Principle

• If the risks or harm from an activity may be greater than any benefit, it makes sense to restrict or stop the activity.

• This is particularly true where the level of risk is as yet unknown.

Salt and Health• Risks: High Blood Pressure, Heart Disease and Strokes

• High Salt diet – Processed food with added salt

• Salt is needed – but no more than about 4g per day

• Current average intake in the UK:• Men - 11g of salt per day• Women - 8g of salt per day

What is an Alkali?

• Chemical Compounds that contain HYDROXIDE ions (OH-)

• Turn Universal Indicator Blue or Purple

• Have a pH over 7, usually between 9 (weak) and 14 (very strong)

Recognising Alkalis

Uses of Alkalis

• Making Soap

• Neutralising Soil

• Making Glass

• Dyeing Cloth

Alkali Reactions

Is it an Alkali?

Sodium Hydroxide

Is it an Alkali?

Water

Is it an Alkali?

It turns Universal Indicator Blue

Is it an Alkali?

Potassium Hydroxide

Is it an Alkali?

Hydrochloric Acid

Is it an Alkali?

Urea (Urine)

Is it an Alkali?

Wasp Sting

Is it an Alkali?

Soapy Water

Is it an Alkali?

Milk

Is it an Alkali?

Ammonium Hydroxide

Is it an Alkali?

Rain water

Is it an Alkali?

It turns Universal Indicator Yellow

Is it an Alkali?

Lithium Hydroxide

Is it an Alkali?

Sulphuric Acid

Is it an Alkali?

Blood

Is it an Alkali?

Bee Sting

Is it an Alkali?

Bleach

Is it an Alkali?

Fizzy Drinks

Is it an Alkali?

Toothpaste

Acid or Alkali?

Magnesium Hydroxide

Acid or Alkali?

It turns Universal Indicator Blue

Is it an Alkali?

Lemon Juice

Acid or Alkali?

Vinegar

Acid or Alkali?

Drain Cleaner

Acid or Alkali?

Bar of Soap

Acid or Alkali?

Stomach Juices

Acid or Alkali?

Aluminium Hydroxide

Acid or Alkali?

It turns Universal Indicator Yellow

Acid or Alkali?

Caesium Hydroxide

Acid or Alkali?

HCl

Acid or Alkali?

NaOH

Acid or Alkali?

KOH

Acid or Alkali?

H2SO4

Electrolysis

• Using Electricity to split up compounds into the original element that they are made from

Chlorine

• Extracted from Salt Water by ELECTROLYSIS

• Toxic Green Coloured Gas

• Very Strong Bleach

• Why would it be added to drinking water?

Risks of Chlorine in Drinking Water

• Chlorine in drinking water can pose potential risks – creating chemicals which are toxic or even carcinogenic

• SO WHY ADD CHLORINE???

• Benefit outweighs the risk

Questions• Why is it important that drinking water is treated

with Chlorine?

• Chlorine is a Toxic gas. How can it be safe to add it to drinking water?

• What potential health risks come from Chlorine in drinking water?

• Why do we continue to add Chlorine, despite the risks is poses?

Electrolysis of Brine

• Brine – Solution of Salt Water

• Salt – Sodium Chloride

• Electrolysis – Splitting up compounds using Electrical Current

Chemical Warning Signs

• Chemistry and Chemicals have their own warning signs of potential hazards

• These help you to take the correct precautions to ensure that you stay safe and risk is minimised.

• What do these hazard symbols stand for?

Flammable

Toxic

Explosive

Corrosive

Harmful (h) or Irritant (i)

Oxidising

Dangerous to the Environment

Assessing Chemical Risk• We need to know:

- How much of it is needed to cause harm

- How much will be used

- How it will be used

- Chance of escaping into the environment

- Who or what it may affect

Chemical Safety

REACH

RegulationEvaluationAuthorisation and restriction of

Chemical Substances

Risks of Plasticisers

• uPVC – Stiff, Tough Plastic used to make many things including Drainpipes, Doors and Window Frames

• PVC – Can be softened by adding PLASTICISERS. These make the plastic softer and more flexible. Used in sheeting, coating for wires and as a leather replacement.

Risks of Plasticisers

What does Sustainable mean?

• Using the Earth’s resources in a way that can continue in the future

• “They won’t run out”

At the end of the Life Cycle

Life Cycle AssessmentCRADLE: What is your product? What materials is it made from?

What raw materials are used? Are they sustainable?

LIFE: What is your product used for? How long will it last? Is any energy or chemicals used in maintaining it during its life? How long is its life likely to be?

GRAVE: What could happen to it at the end of its life? List all the alternatives and what would happen to it in this stage. Which of these is the best option and why?

LCA

Revision Summary

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