Chemistry: Structured Paper C3 - Topic 4
Chemistry Revision Cards.
- Created by: Rebecca Wright
- Created on: 23-05-11 20:02
Transition Metals
Transition metals are:-
- good conductors of heat
- very dense, strong and shiny
- not very reactive
- have very high melting points
Copper is used for wiring because it doesn't react with water.
Iron is malleable and is used to make utilities like cooking pots.
Catalysts:
Iron > Haber Process
Manganese Oxide > Hydrogen Peroxide
Nickel > Turning oils into fats
Vandium Pentoxide > Contact Process
COMPOUNDS ARE VERY COLOURFUL
Alcohols
ALCOHOLS
- Flammable
- They burn to produce carbon dioxide and water.
- They're all toxic!!
Alcohols are used as solvents;
Ethanol is used in perfumes and aftershaves
Methylated spirits are used to clean paint brushes etc.
Alcohols are also used as fuels.
Carboxylic Acids
They're often called organic acids.
Their names end in '-anoic acid' and start with:
- meth
- eth
- prop
- but
- pent
they mix with water and with solvents like alcohols.
ethanoic acid + magnesium > hydrogen + magnesium ethanoate
Ethanoic acid is the acid in vinegar.
Citric acid is present in oranges and lemons.
Aspirin is a man made organic acid - used as a pain killer.
Esters
Esters are formed from an alcohol and a carboxylic acid.
alcohol + carboxylic acid > ester + water
the acid catalyst used is sulphuric acid.
Esters don't mix well with water:
esters are generally neutral, colourless liquids with low boiling points.
many of them have pleasant smells.
many esters are flammable!!
they're used for perfumes, aromas, ointments and solvents for paint, ink glue etc.
Electrolysis
Oxidation is the loss of electrons. > Reduction is the gain of electrons.
Electrolysis is used to get very pure copper.
The electricity supply acts by:
- Pulling electrons off the anode > they turn into Cu2+ ions.
- These electrons are offered to the cathode (to turn 'em back)
- The impurities are dropped at the anode as a sludge
- Pure copper atoms bond to the cathode
Electrochemical Cell - Makes electricity
The Alkali Metals
Alkali metals are unusual for metals!!
- they're soft!
- silvery-white
- low density
- lower melting and boiling points
- metallic bonds in these metals are a lot weaker
> but, they are shiny, and good conductors.
when LITHIUM, SODIUM or POTASSIUM are put in WATER, they react vigorously. moving around and fizzing!! This reaction produces hydrogen.
Sodium carbonate is used to make glass and soda crystals.
Sodium carbonate, sand and limestone are mixed and heated at 1500C
Sodium Hydroxide is a strong alkali with many industrial uses.
soaps, oven cleaner, bleach.
Sulphuric Acid
The contact process is used to make sulphuric acid!
- Sulphur is burned in air to make sulphur dioxide
- It is then oxidised to make sulphur trioxide
- It is dissolved in concentrated sulphuric acid to make it fuming
- diluted with water to make concentrated sulphuric acid
- a VANADIUM PENTOXIDE catalyst is used
Sulphuric acid is used in:
- car batteries
- manufacturing
- petroleum refining
- cleaning and preparing metal surfaces
Detergents
Surfactants lower the surface tension...
Detergents and soaps contain substances called surfactants, these molecules have a
hydrophobic part (doesnt like water, loves dirt and grease)
and a
hydrophilic part (loves water, hates dirt and grease)
When an ester reacts with an alkali, you get soap!
ACID + ALKALI = SALT + WATER
Soaps form scum in hard water areas. - insoluble salts.
Biological detergents contain enzymes, Non-Biological detergants don't.
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