How can perfumes be natural or artificial?
- esters are often used in perfumes
- esters are common in natural
- esters can be manufactured synthetically to use as perfumes or flavouring
What is the process of esterification?
-carboxylic acid+alcohol–>ester+water
1-mix 10cm3 of both a carboxylic acid and alcohol
2-add 1cm3 of concentrated sulfuric acid as an acid catalyst
3-warm gently for 5 minutes
4-add 150cm3 of sodium carbonate solution to neutralise the acids
5-smell carefully by wafting the smell to your nose
-the fruity-smelling product is the ester
What are the needed properties of perfumes?
- easily evaporates or it won’t reach any noses
- non-toxic: it mustn’t seep through your skin and poison you
- doesn’t react with water: or it could react to water in sweat
- doesn’t irritate skin: or you can’t apply directly to skin
- insoluble in water: if it was soluble in water is would wash off every time you got wet
What are peoples opinions on testing cosmetic products on animal?
- worth testing on animals first to check it won’t damage humans
- it’s wrong to cause suffering to animals just to test the safety of cosmetics (especially when the results may be inconclusive)
Why has testing cosmetics on animals been banned in the EU?
-because of concerns of animal welfare
What are the properties of a solid?
- strong intermolecular forces of attraction
- particles don’t move
- definite shape and volume
- do not flow
- particles vibrate as they get hotter, causing them to expand slightly
What are the properties of a liquid?
- some intermolecular forces of attraction
- particles are free to move but tend to stick together
- don’t keep a definite shape
- keep the same volume
- will flow to the bottom of a container
- particles constantly moving in random motion
- the hotter the faster they move
What are the properties of a gas?
- no intermolecular forces of attraction
- free to move
- travel in straight lines and only interact when they collide
- no define shape or volume
- always fill any container
- particles move constantly with random motion
- hotter=faster
How do we smell thing?
- liquid particles are heated they move faster
- some faster than others
- fast-moving particles at the surface will overcome the forces of attraction from the other particles and escape
- this is evaporation
- evaporated particles drift in the air
- smell receptors in our noses pick up the the chemical and we smell it
What are the forces like in perfumes?
- the forces of attractions need to be very weak (volatile)
- you only need a little heat energy to evaporate perfume
- its easy for the particles to overcome this attraction and escape
What is volatility?
-how easily a liquid evaporates
