C1 (1) Flashcards
What charge is given when an atom loses an electron in bonding?
Positive
What charge is given when an atom gains an electron in bonding?
Negative
What is an ion?
A charged atom
What are four additives that are added to foods and why?
Colouring = enhance appearance
Flavour enhancers = improve taste and smell
Anti?oxidants = preserve food
Emulsifiers = help oil and water to mix
What does an emulsifier have? (structure)
Hydrophobic tail (hates water, likes oil) Hydrophilic head (hates oil, likes water)
What happens when you shake oil and water together with an emulsifier?
Oil forms droplets surrounded by emulsifier with hydrophilic tail facing out. Other oil droplets are repelled but water attaches.
What are four reasons foods are cooked?
Better taste and texture
Easier to digest Eg. Potatoes
High temps kill microbes
Destroy poisons
What happens to eggs and meat when cooked?
Denature (change shape) because the energy breaks some of chemical bonds and the molecules take on a different shape
What happens when you heat baking powder?
Undergoes thermal decomposition
What is thermal decompoisiton?
When a substance breaks down into simpler substances when heated
What is the equation for baking powders thermical decomposition? (Sodium hydrogencarbonate)
Sodium hydrogencarbonate = sodium carbonate + carbon dioxide + water
2NaHCO(3) = Na(2) CO(3) + CO(2) + H(2)0
Why is baking powder used in baking?
CO(2) is released which makes cakes rise
What is esterification?
Heating a carboxylic acid with alcohol
An acid catalyst is usually used too
What is the esterification equation?
Acid + Alcohol = Ester + Water
What five properties to perfumes need and why?
Easily evaporates = to smell it
Non?toxic = won’t poison you
Unreactive with water = would react with sweat
Doesn’t irritate skin = could risk burning skin
Insoluble in water = so it doesn’t wash off
What are reasons for animal testing?
To check it won’t damage humans
What are reasons against animal testing?
Wrong to cause harm
Results might not be conclusive
Describe the following points in a solid
? Forces between particles
? Particle movement/shape
? Effect of heat
?Strong forces of attraction
?Don’t move (definite shape and volume)
? Vibrate more
Describe the following points in a liquid
? Forces between particles
? Particle movement/shape
? Effect of heat
?Some forces of attraction = free to move passed each other
?Don’t keep definite shape but keep same volume
? Move faster = liquid to expand
Describe the following points in a gas
? Forces between particles
? Particle movement/shape
? Effect of heat
?No force of attraction = free to move
?Don’t keep definite shape nor volume. Always fill any container
?Either expand or pressure increase
What is volatility?
How easy a liquid evaporates
What is evaporation?
When fast moving particles at surface overcome forces of attraction and escape
What is a solution?
A mix of a solute and solvent
What is a solute?
The substance being dissolved
What is a solvent?
The liquid it’s dissolving in to
What is soluble?
It will dissolve
What is insoluble?
It will NOT dissolve
What is solubility?
A measure of how much will dissolve
Why doesn’t nail varnish dissolve in water?
The attraction to themselves is stronger than the attraction between each other
Why does nail varnish dissolve in nail varnish remover?
The attraction between acetone molecules and nail varnish molecules is stronger than the attractions holding both substances together
What three things are in paint?
Pigment
Binding medium
Solvent
What is a pigment?
Gives paint its colour
What is a binding medium?
Holds the paint together
What is the purpose of a solvent in paint?
Thins the paint (easier to spread)
What is a colloid?
Really small particles are dispersed in another substance but do not dissolve
Why don’t colloids seperate out?
The particles are too small
How do water based paints dry?
The solvent (water) evaporates leaving binder (acrylic or vinyl acetate polymer) and pigment as a thin solid film
What are the advantanges of water based paints?
Fast drying and don’t release harmful fumes
How do oil based paints dry?
Solvent (organic compound) evaporates and the oil (binder) is oxidised before turns solid
What are the advantages and disadvantages of oil paints?
Glossy, water proof and hard wearing
Produce harmful fumes
What is a thermochromic pigment?
Change colour or become transparent when heated or cooled
What are examples of when thermochromic pigments are used?
Electric kettles
Baby products (bath toys, spoons, bottles)
Drink mugs
How do phosphorescent pigments glow in the dark?
Absorb natural or artificial light and store the energy in their molecules. This energy is then released as light over a period of time
What are polymers?
Long chain molecules
When are polymers formed?
When lots of monomers join together = polymerisation
Do alkenes or alkanes make addition polymers?
Alkenes because they have at least one double covalent bond so they can open them up to join together to form polymer chains
Describe the properties of a thermosoftening plastic
Held together by weak intermolecular forces
?Low melting points
?Soft and mouldable (chains can slide over ech other)
Describe the properties of a thermosetting plastic
Held together by crosslinking bonds and strong intermolecular forces
?High melting points
?Rigid and can’t be stretched
Compare GoreTex and Nylon
They are both waterproof
However GoreTex is ‘breathable’ = allows water vapour to pass through
How is GoreTex made?
Laminating a thin film of expanded PTFE onto nulon of polyester. PTFE = sturdier
How is GoreTex breathable AND waterproof?
?PTFE = tiny holes = let water vapour through but too small for rain to pass through
?PTFE repels water
What are the two disposal options for non?biodegradable plastics? What are their disadvantages?
Landfill = long time to decompose, wastes land and plastic Incineration = releases toxic gases
What is a hydrocarbon?
A compound formed from carbon and hydrogen atoms ONLY
Are alkanes saturated or unsaturated compounds?
Saturated because they contain ONLY single bonds between carbon atoms.
Single C?C bonds
Why can alkanes not form polymers?
No double bonds to open up to allow molecules to join
What bonds hold atoms in hydrocarbons together?
Covalent (share electrons) because this way both atoms get a full outer shell
Are alkenes saturated or unsaturated compounds?
Unsaturaed because they contains one or more double covalent bonds in between atoms
C=C
How can you test if a hydrocarbon is an alkane or alkene?
Add bromine water to substance
If the liquid decolories = alkene (bromine added to double bond)
Stays orange = alkane
