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58 Cards in this Set
- Front
- Back
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?
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Negative
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What is an ion?
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A charged atom
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What are four additives that are added to foods and why?
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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)
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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?
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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?
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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?
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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?
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Undergoes thermal decomposition
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What is thermal decompoisiton?
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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)
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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?
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CO(2) is released which makes cakes rise
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What is esterification?
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Heating a carboxylic acid with alcohol
An acid catalyst is usually used too |
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What is the esterification equation?
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Acid + Alcohol = Ester + Water
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What five properties to perfumes need and why?
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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?
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To check it won't damage humans
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What are reasons against animal testing?
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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?
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How easy a liquid evaporates
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What is evaporation?
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When fast moving particles at surface overcome forces of attraction and escape
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What is a solution?
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A mix of a solute and solvent
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What is a solute?
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The substance being dissolved
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What is a solvent?
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The liquid it's dissolving in to
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What is soluble?
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It will dissolve
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What is insoluble?
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It will NOT dissolve
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What is solubility?
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A measure of how much will dissolve
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Why doesn't nail varnish dissolve in water?
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The attraction to themselves is stronger than the attraction between each other
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Why does nail varnish dissolve in nail varnish remover?
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The attraction between acetone molecules and nail varnish molecules is stronger than the attractions holding both substances together
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What three things are in paint?
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Pigment
Binding medium Solvent |
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What is a pigment?
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Gives paint its colour
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What is a binding medium?
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Holds the paint together
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What is the purpose of a solvent in paint?
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Thins the paint (easier to spread)
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What is a colloid?
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Really small particles are dispersed in another substance but do not dissolve
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Why don't colloids seperate out?
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The particles are too small
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How do water based paints dry?
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The solvent (water) evaporates leaving binder (acrylic or vinyl acetate polymer) and pigment as a thin solid film
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What are the advantanges of water based paints?
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Fast drying and don't release harmful fumes
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How do oil based paints dry?
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Solvent (organic compound) evaporates and the oil (binder) is oxidised before turns solid
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What are the advantages and disadvantages of oil paints?
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Glossy, water proof and hard wearing
Produce harmful fumes |
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What is a thermochromic pigment?
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Change colour or become transparent when heated or cooled
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What are examples of when thermochromic pigments are used?
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Electric kettles
Baby products (bath toys, spoons, bottles) Drink mugs |
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How do phosphorescent pigments glow in the dark?
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Absorb natural or artificial light and store the energy in their molecules. This energy is then released as light over a period of time
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What are polymers?
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Long chain molecules
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When are polymers formed?
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When lots of monomers join together = polymerisation
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Do alkenes or alkanes make addition polymers?
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Alkenes because they have at least one double covalent bond so they can open them up to join together to form polymer chains
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Describe the properties of a thermosoftening plastic
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Held together by weak intermolecular forces
-Low melting points -Soft and mouldable (chains can slide over ech other) |
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Describe the properties of a thermosetting plastic
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Held together by crosslinking bonds and strong intermolecular forces
-High melting points -Rigid and can't be stretched |
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Compare GoreTex and Nylon
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They are both waterproof
However GoreTex is 'breathable' = allows water vapour to pass through |
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How is GoreTex made? |
Laminating a thin film of expanded PTFE onto nylon of polyester. PTFE = sturdier |
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How is GoreTex breathable AND waterproof?
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-PTFE = tiny holes = let water vapour through but too small for rain to pass through
-PTFE repels water |
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What are the two disposal options for non-biodegradable plastics? What are their disadvantages?
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Landfill = long time to decompose, wastes land and plastic
Incineration = releases toxic gases |
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What is a hydrocarbon?
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A compound formed from carbon and hydrogen atoms ONLY
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Are alkanes saturated or unsaturated compounds?
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Saturated because they contain ONLY single bonds between carbon atoms.
Single C-C bonds |
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Why can alkanes not form polymers?
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No double bonds to open up to allow molecules to join
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What bonds hold atoms in hydrocarbons together?
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Covalent (share electrons) because this way both atoms get a full outer shell
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Are alkenes saturated or unsaturated compounds?
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Unsaturaed because they contains one or more double covalent bonds in between atoms
C=C |
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How can you test if a hydrocarbon is an alkane or alkene?
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Add bromine water to substance
If the liquid decolories = alkene (bromine added to double bond) Stays orange = alkane |