Chemistry
- Created by: florence
- Created on: 05-03-13 19:00
safety
corrosive
safety
flammable
safety
toxic
safety
harmful/irritant
safety
if your clothes catch fire:
.don't run around
.lie down
.smother the flames
.roll around
safety
if you get alkali in your eye:
.run water over the eye
.get a friend to tell the teacher
.keep irrigating your eye
.go to hospital
safety
rules for specific situations
.clear floor
.don't eat in the lab
.wear goggles if needed
.wear a lab coat if needed
.keep tops on bottles unless pouring
.never hold or carry a bottle by it's neck
.tie hair back
.no loose clothing
.when a bunsen burner is not in use, close air-hole so a yellow flame can be seen
.don't point testubes at yourself or anyone else
.never look directly into a testube
.wash your hands after handling chemicals or biological materials
.put any waste solids in the special 'bits' bins
safety
if an accident happens:
.wipe up small accidents
.report big accidents to teacher
.if you get something in your mouth, spit it out and wash your mouth out with plenty of water
.if you are burnt or get a chemical on your skin, wash the effected skin with cold water
.report breakages to teacher
.broken glass should go in the special 'glass' bin
atmosphere
general info:
.the atmosphere is a mixture of gases that surrounds the earth
.the composition of todays atmosphere is very different from the composition of the earths early atmosphere which contained higher levels if H2O vapour and CO2, and very little O2
.the atmosphere we are currently living in is composed of 78% nitrogen, 21% oxygen and the remaining 1% contains many gases, including water vapour, CO2 and argon.
.all the gases in the air have NO smell or colour
atmosphere
nitrogen:
.main gas in atmosphere
.INSOBLUBE in water
.DOESN'T REACT EASILY with other substances (good incase of natural disasters; if it reacted badly with other substances it could make them worse)
.used to package food because it is mostly unreactive and insolube
.however can react, used to make ammonia and nitric acid
atmosphere
oxygen:
.REACTS WITH ALOT of substances
.SOLUBLE in water
.vital for life
.used for respiration (the process to release energy from sugars)
.is used in cylinder of gas in hospitals to help people with breathing problems
.used to help substances burn better
atmosphere
argon:
.VERY UNREACTIVE with other substances
.INSOLUBLE in water
.used to fill light bulbs so that the filiment doesn't burn out (because in is insoluble in water and very unreactive)
atmosphere
carbon dioxide:
.FAIRLY UNREACTIVE with other substances
.INSOLUBLE in water
.used to assist green plants with photosynthesis because it is soluble in water and fairly unreactive
.sometimes used in fire sxtinguishers
.in fizzy drinks
experiment (atmosphere)
founding out the amount of oxygen in the air:
.in this experiment copper is burning
as it does it uses the oxygen to form copper oxide
.let the apparatus cool down before taking the reading on the syringe because this will make your results more accurate, as gases expand when they're heated
.the sources of error in this experiment are:
taking measurements when the gases are still hot
if not all the copper has reacted, there might be some oxygen left
you might have the wrong amounts of materials needed
repitition would make it more reliable
experiment (gases and testing preparation)
solubility of oxygen:
.as the temperature of the water increases the solubility of oxygen increases
.solubilty of oxygen in water is measures in g/100g of water
.you would measure the solubility of oxygen
experiment (gases and testing preparation)
preparing oxygen gas:
.collect 2 spatulas of magnesium (IV) oxide in a flask
insert a thistle funnel and delivery tube
fill a boiling tube with water in a trough
stand it upright (keep the mouth of the tube under the surface of the water)
.the manganese oxidcd the rate of reaction as it acted as a catalyst - speeding up the reaction without being altered itself
the reaction:
hydrogen pyroxide → water + oxygen
(H2O2) (H2O) (O2)
.heat was also produced as this reaction is EXOTHERMIC (produces heat)
We proved that oxygen was made by testing it with a glowing split that was re-lit when we put it into the boiling tube because oxygen was present
metals and non-metals
metals:
.some metals: zinc, tin, nickel, aluminium, copper, lead, iron
.metals are good conducters of heat
.metals are good conducters of electricity
.metals go dull when they are in air
this is called corrosion
rusting is a form of corrosion
.metals are shiny, malleable, sonorous, strong and sometimes magnetic
.most elements are metals
.there are about 70 metallic elements
.metals are some of the most important materials
metals and non-metals
non-metals:
.DON'T conduct electricity well
.DON'T conduct heat well
.not shiny, dull, no free flowing electrons
.there are only about 20 non-metallic elements
.very few non-metals are useful materials
metals and non-metals
testing for metals/non-metals:
.conducting electricity test
metals conduct electricity well, non-metals don't
.conducting heat test
metals conduct heat well, non-metals don't
.brittle test
metals are NOT brittle, non-metals are
elements
copper:
.conducts electricity well
.used for wires
elements
carbon:
.barbeque charcoal
.burns well to give lot's of heat
elements
chlorine:
.kills germs in swimming pools and water supplies
elements
gold:
.stays shiny
.used for jewellery
elements
aluminium:
.very light
.used for window frames
elements
helium:
.very light
.used in balloons
elements
titanium
.very hard
.used for aeroplane parts
elements
oxygen:
.gas we use in our bodies which is taken in by the lungs
elements
mercury:
.liquid metal
experiment (burning magnesium)
does magnesium change when it burns?:
method:
.weigh a crucible and it's lid on a balance
record it's mass
add a piece of metal to the crucible and re-weigh
record the mass
heat the crucible using a heat flame
after every minute remove the lid for 10 seconds and then put the lid back on (use tongs and avoid touching the crucible once heated as it will be extremely hot) heat for 5 minutes then leave to cool
re-weigh the crucible, it's contents and the lid record the mass
.when the metal was heated it lost (?) 0.2g in mass
reactants product
magnesium +oxide → magnesium oxide
.when the magnesium burns it reacts with the oxygen in the air to form magnesium oxidethe magnesium oxide has a greater mass than the magnesium because the mass of the oxygen has been added to the mass of the magnesium
experiment (metals and non-metals)
heating metals and non-metals:
magnesium sulphur
observations shiny, malleable, yellow
before solid
heating
observations burns -white, bright melts - becomes a liquid
while light produces a burns with a blue flame
heating white powder
observations the indicator turns the indicator turns yellow/
with blue/purple red - acid
indicator - alkali
metals and non-metals
metal and non-metal oxides:
.usually metal oxides have a high pH
.usually non- metal oxides have a low pH
.metal oxides are alkali
.non-metal oxides are acid
experiment (acids and carbonates)
preparing carbon dioxide:
acid + carbonate → salt + water + carbon dioxide
2HCI + CaC03 → CaCI2 + H 20 + C02
.carbon dioxide can be prepared by reacting an acid (in this case hydrochloric acid) with a carbonate (in this case carbonate CaC03)
.carbon and oxygen
.carbon burns producing carbon dioxide
.carbon dioxide is a non-metal oxide
.carbon monoxide is a non-metal oxode produced when carbon burns in a limited supply of oxygen
this causes the reactants to fizz violently as the carbon dioxide is produced
carbon dioxide is heavier than air so it will DISPLACE the air inside the gas jar and push it UPWARDS
to test if the gas produced is C02 we can use LIMEWATER
when C02 is bubbled through limewater a white PRECIPITATE is formed which makes the limewater CLOUDY
acids and carbonates
what will happen when acids mix with carbonates:
.give off bubbles of gas
.majority turned limewater (used in this experiment) cloudy
.when a metal carbonate reacts with an acid, it fizzes giving off carbon dioxide
.when a metal carbonate reacts with an acid the products are a salt, carbon dioxide and water
metal carbonate + acid → salt + carbon dioxide + water
acids and carbonates
precipitate - a solid formed by the reaction of two solutions
2C02(g) + Ca(OH)2 (aq) => CaC03 + H2O (l)
.the salt produced depends on the metal carbonate and type of reaction:
.when a metal carbonate reacts with hydrochloric acid the salt produced is metal chloride
.when a metal carbonate reacts with suphuric acid the salt produced is metal sulphate
.when a metal carbonate reacts with nitric acid it produces metal nitrate
thermal decomposition
thermal decomposition: a chemical reaction in which heat breaks a compound down in to two or more products
.the more reactive a metal is, the harder it is to decompose it's carbonate by heating
experiment (thermal decomposition)
.as the copper carbomate is heated, a gas is formed which travels to the limewater and turns it cloudy
.the copper carbonate changes colour from green to black as it is heated
.the thermal decomposition of copper carbonate:
copper carbonate → carbon dioxide + copper oxide
CuCO3 → CO2 + CuO
experiment (thermal decomposition)
aim: to find out which carbonates break down most easily
apparatus: spatula, stop clock, stand, clamp, boss, carbonates, limewater, measuring cylinder, digital balance
method:
1. measure 10cm³ of limewater with a measuring cylinder
2. set up apparatus as seen beneath
3. measure 2g of carbonate and put it in boiling tube 1 (check diagram in chem book)
4. heat the carbonate
5. repeat for all carbonates
thermal decomposition
(decrease, going down, in reactivity)
potassium
sodium
calcium
magnesium
aluminium
manganese
zinc
iron
copper
silver
gold
experiment (acid rain)
are all rocks and buildings effected by acid rain?:
method:
1. put on a lab coat and goggles
2. place the specimin of your building material on a watch glass
3. use a pipette and place 1cm³ of acid on to your specimin
4. if your specimin is a carbonate, watch for bubbling
5. for all specimins, watch for a reaction
conclusion:
some of the materials we tested were effected by acid but most weren't
of the materials we tested marble and limestone reacted but brick, granite, slate, sandstone and iron didn't
the marble bubbled and fizzed
the limestone vigorously fizzed and had a strong smell
acid rain
.sulphur is a non-metal
.when it reacts with oxygen it forms sulphur oxide (SO2)
sulphur + oxygen → sulphur dioxide
.the acidity is mainly due to dissolved sulphur dioxide and nitrogen dioxide from air pollution
.acids react with all calcium carbonates and therefore damage all limestone/marble buildings
.problems of acid rain:
erodes stonework
damages paint on cars
pollutes lakes and rivers
damages plants
.the problem of acid rain in britain has been decreased by:
burning less fossil fuels
removing sulphur from fossil fuels before they are burned
removing sulphur dioxide from flue gases
acid rain
type of material observations when acid added does acid effect the material
brick nothing happened no
marble bubbling and fizzing yes
granite nothing happened no
slate nothing happened no
limestone vigurously fizzed, strong smell yes
sandstone nothing happened no
iron nothing happened no
gases
gases are:
invisible
not solids or liquids
no shape or size
no limit on mass
gases
helium (He)
.element + molecule
.light, colourless, odourless
.won't burn
.can be turned in to a liquid and used for fridges
.sound has a higher frequency in helium
.makes balloons float
gases
nitrogen (N2)
.molecule
.no colour, no smell, no taste
.makes up about 4/5's of the air
.put in crisp packets to stop squashing
.put in racing car tyres
gases
argon (Ar)
.element + molecule
.colourless, odourless
.forms a very small part of the air
.used in light bulbs and radio tubes
gases
carbon dioxide (CO2)
.dense, colourless, odourless
.formed when any fuel containing carbon is burned
.found in air breathed out of animals' lungs
.plants use it in photosynthesis
.used in fizzy drinks/fire extinguishers
gases
oxygen (O2)
.molecule
.colourless, odourless, tasteless
.animals and plants need it for respiration
.fire needs it to burn
gases
hydrogen (H2)
.molecule
.colourless, odourless
.almost insoluble in water
.far lighter than air (lightest gas)
.burns readily in air
molecules etc re-cap
molecule: made up of two or more atoms
compound: made of more than one type of atom/element, joined together by chemical bonds
mixture: a substance composed of 2 (two) or more elements (compounds) that are physically mixed together, but not chemically combined
atom: a single atom
element: pure substance, made of one type of atom
experiment (hydrogen preparation)
(check diagram in book)
.dilute suphuric acid is added to granulated zinc in a flask via a thiste funnel
.the hydrogen gas is collected by downward displacement of water
zinc + sulphuric acid => zinc sulphate + hydrogen
Zn(s) + H2SO(aq) =>ZnSO4(aq) + H2(g)
.test for hydrogen:
explodes with a vicious pop in the presence of air (oxygen) when a flame is introduced
hydrogen
.when hydrogen burns, water is the only product
H2 + O2 => H2O
.tests for water - H2O
1. water has no colour or smell
2. water puts out a lit splint
3. water or it's vapour will turn cobalt chloride paper from blue to pink
4. water or it's vapour turns anhydrous copper (II) sulphate crystals from white to blue
5. water melts at 0°C and boils at 100°C
hydrogen
making hydrogen from water:
.water can be split by passing electric current through it in a process called electrolysis
.this is the decomposition of water into oxygen and hydrogen due to an electric current being passedthrough the water
.prouduction of hydrogen from water requires large amounts of energy and is uncompetitive with production from coal or natural gas
the greenhouse effect and global warming
.gases in the atmosphere such as carbon dioxide, methane, nitrous oxides and CFC's (greenhouse gases) trap the infra red radiation (heat) from the sun that is reflected back from earth
.the greenhouse effect is to do with heat transferred and stored in our atmosphere.
it is caused by a layar of gases (predominantly carbon dioxide and methane) which prevent heat hitting the earths surface and reflecting back into space, heating our atmosphere
.the ozone layer is a layer of gas in our atmosphere
when holes are produced in the ozone layer by man-made gases (e.g. CFC's) it becomes possible for UV light to reach the surface of the planet
UV light increases the risk of skin cancer
.over the past century there has been a steep increase in temperature - proof for global warming
formulae
things to check tohelp you write formula:
1. is the chemical an element or a compound
- iron is an element, so it's symbol is it's formula
- there are 7 exceptions I2, Br2, Cl2, F2, O2, N2, H2 - these are all DIATOMIC molecules (2 atoms)
2. If the chemical is a compound does the name tell you the formula?
- the name contains mon, di, tri
e.g. carbon MONoxide - CO
carbon DIoxide- CO2
(check book for diagrams)
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