C1 (1) Flashcards by Katie Walmsley

What charge is given when an atom loses an electron in bonding?

Positive

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What charge is given when an atom gains an electron in bonding?

Negative

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What is an ion?

A charged atom

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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

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What does an emulsifier have? (structure)

Hydrophobic tail (hates water, likes oil)
Hydrophilic head (hates oil, likes water)

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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.

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What are four reasons foods are cooked?

Better taste and texture
Easier to digest Eg. Potatoes
High temps kill microbes
Destroy poisons

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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

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What happens when you heat baking powder?

Undergoes thermal decomposition

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What is thermal decompoisiton?

When a substance breaks down into simpler substances when heated

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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

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Why is baking powder used in baking?

CO(2) is released which makes cakes rise

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What is esterification?

Heating a carboxylic acid with alcohol

An acid catalyst is usually used too

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What is the esterification equation?

Acid + Alcohol = Ester + Water

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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

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What are reasons for animal testing?

To check it won’t damage humans

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What are reasons against animal testing?

Wrong to cause harm

Results might not be conclusive

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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

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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

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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

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What is volatility?

How easy a liquid evaporates

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What is evaporation?

When fast moving particles at surface overcome forces of attraction and escape

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What is a solution?

A mix of a solute and solvent

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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