Chemistry Revision

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Chemistry Revision
Introducing Chemistry
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Particles

• All matter is made up of very small particles
  which may be _____, molecules or ions.
• The particles are continually moving - the amount
  of movement depends on the state of the matter.

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Solids

• Particles
• are very close together
• only vibrate
• have strong forces of attraction

Properties
Solids have a definite volume a
definite shape a high density
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Liquids
Particles are close together move around have
weak forces of attraction
Properties
Liquids have a definite volume
have no definite shape can be poured
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Gases
Particles are very far apart move around
quickly have no force of attraction
Properties
Gases have no definite volume have
no definite shape can be compressed
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Change of State

• SOLID LIQUID GAS
• SUBLIMATION

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Elements, Mixtures and Compounds

• Element a substance which contains only one
  type of atom
• Compound a substance which contains two or more
  different elements chemically joined together in
  fixed proportions
• Mixture different elements and/or compounds
  mixed together in any proportion

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Identify these diagrams as elements, compounds or
mixtures.
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Identify these diagrams as elements, compounds or
mixtures.
1 Compound 2 Mixture of two different
compounds 3 Element 4 Mixture of a compound
and two different elements 5 Two different
elements
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Identify these substances as elements, compounds
or mixtures.

• air iron
• distilled water sea water
• oxygen carbon dioxide
• sodium chloride milk
• crude oil copper
• calcium carbonate sulphur
• iron sulphide petrol

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Separating Mixtures

• You should know when to use the following methods
  
• filtration simple distillation
• chromatography fractional distillation
• crystallisation evaporation

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Which method?

• 1. Remove fine traces of sand from seawater
• 2. To obtain pure water from seawater
• 3. To remove alcohol from beer
• 4. To separate food colouring in sweets
• 5. To obtain copper sulphate crystals from copper
  sulphate solution
• chromatography filter fractional distillation
• crystallisation simple distillation

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Which method?

• 1. Filter
• 2. Simple distillation
• 3. Fractional distillation
• 4. Chromatography
• 5. Crystallisation

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Acids, Bases and Salts

• Solutions can be either acidic, basic or _____.
• We can use indicators to judge this.
• Litmus turns red in ________and _____in alkali.
• Universal indicator is a better indicator because
  it tells us the ________ of the acid or alkali.

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The pH scale
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Acids

• Acids contain hydrogen ions (H) and water.
• Hydrochloric acid HCl
• Nitric acid HNO3
• Sulphuric acid H2SO4
• Know their formulas!

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Bases and Alkalis

• A base is the oxide of a ________.
• An example is copper oxide.
• An alkali is a soluble base.

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Alkalis

• Some common alkalis are
• sodium hydroxide NaOH
• calcium hydroxide Ca(OH)2
• ammonium hydroxide NH4OH
• Know their formulas!

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Salts

• Salts are made when acids react.
• hydrochloric acid makes __________salts
• nitric acid makes __________salts
• sulphuric acid makes __________salts

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Reactions of Acids

• ACID METAL SALT _______
• ACID BASE SALT _______
• ACID ALKALI SALT _______
• ACID CARBONATE SALT WATER
• 
  _______ _______

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Reactions of Acids

• ACID METAL SALT HYDROGEN
• ACID BASE SALT WATER
• ACID ALKALI SALT WATER
• ACID CARBONATE SALT WATER
• CARBON
  DIOXIDE

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Test for Hydrogen

• Hydrogen is flammable and explosive in air.
• It gives a squeaky ___ with a _______ splint.

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Test for Carbon Dioxide

• It turns ________ (calcium hydroxide) cloudy

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Writing Formulas

• Group 1 2 3 4 5 6 7
  0
• Combining 1 2 3 4 3 2 1 0
• Power

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Formulas

• The formulas of some ions need to be learnt.
• ammonium NH4
• hydroxide OH-
• nitrate NO3-
• sulphate SO42-
• carbonate CO32-

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Formulas

• Some elements do not exist as single atoms so
  when writing equations remember that
• oxygen is O2
• nitrogen is N2
• hydrogen is H2
• chlorine is Cl2
• bromine is Br2
• iodine is I2

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Writing Equations

• Step 1 Write a word equation for the reaction.
• Step 2 Substitute formulas for words.
• Step 3 Balance the equation by adding numbers
  in front of the formulae.
• Step 4 Add the state symbols.

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Equations

• Example
• Step 1 calcium oxygen calcium oxide
• Step 2 Ca O2
  CaO
• Step 3 2Ca O2 2
  CaO
• Step 4 2Ca(s) O2(g) 2
  CaO(s)

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Equations

• Sodium water sodium hydrogen
• hydroxide

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Equations

• Sodium water sodium hydrogen
• hydroxide
• Na H2O NaOH H2

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Equations

• Sodium water sodium hydrogen
• hydroxide
• 2Na 2H2O 2NaOH
  H2

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Equations

• Sodium water sodium hydrogen
• hydroxide
• 2Na(s) 2H2O(l) 2NaOH(aq) H2(g)

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Energy Transfer in Reactions

• Energy must be supplied Energy is
  released when
• to break chemical bonds chemical
  bonds are formed
• Energy In Energy Out
• In a reaction, if
• The energy needed to is LESS The energy
  released
• break existing bonds than from
  forming new bonds
• then the reaction is EXOTHERMIC

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Energy Transfer in Reactions

• Energy must be supplied Energy is
  released when
• to break chemical bonds chemical
  bonds are formed
• Energy In Energy Out
• In a reaction, if
• The energy needed to is MORE The energy
  released
• break existing bonds than from
  forming new bonds
• then the reaction is ENDOTHERMIC

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Energy diagrams - Exothermic

• Energy
• Level
• Activation
• Reactants Energy
• Heat of
• Reaction
• (-ve)
• Products
• Progress of reaction

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Energy diagrams - Endothermic

• Energy
• Level
• Products
• Activation Heat of
• Energy Reaction
• Reactants (ve)
• Progress of reaction

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Reactions

• Exothermic
• These are reactions which release energy to the
  surroundings.
• The temperature of the surroundings rises.
• Example
• magnesium hydrochloric magnesium
  hydrogen
• acid chloride

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Reactions

• Mg(s) 2HCl(aq) MgCl2(aq)
  H2(g)

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Reactions

• Endothermic
• These are reactions which take in energy from the
  surroundings.
• The temperature of the surroundings drops.
• Example
• ammonium water ammonium
  nitrate
• nitrate solution

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Reactions

• Neutralisation
• sodium sulphuric sodium _____
• hydroxide acid sulphate

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Reactions

• Neutralisation
• sodium sulphuric sodium water
• hydroxide acid sulphate
• 2NaOH(aq) H2SO4(aq) Na2SO4(aq)2H2O(l)
• This is an EXOTHERMIC reaction

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Reactions

• Combustion
• methane oxygen carbon water
• dioxide

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Reactions

• Combustion
• methane oxygen carbon water
• dioxide
• CH4(g) 2O2(g) CO2(g) 2H2O(l)
• This is an _____________reaction
• Atmospheric pollution/global warming
• Incomplete combustion

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Chemistry Revision
Metals and the Reactivity Series
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Reactivity Series

• An order of reactivity of metals can be built up
  by looking at the reactions of metals.

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Metals with Oxygen

• Nearly all the metals react with oxygen to form
  OXIDES.
• copper oxygen copper oxide

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Metals with Water

• Some metals react with water to produce
  hydroxides (or oxides) and hydrogen.
• Sodium water sodium hydrogen
• hydroxide

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Metals with Acids

• Many metals react with acids to produce a salt
  and ___________.
• Zinc sulphuric zinc
  _______
• acid sulphate

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Reactivity Series

• Element Reaction with Reaction with
  Reaction with
• Oxygen Water Acid
• potassium
• sodium Burn brightly
• calcium when heated
• magnesium
• aluminium
• carbon
• zinc React slowly
• iron when heated
• tin
• lead
• hydrogen
• copper
• silver No reaction
• gold when heated

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Reactivity Series

• Element Reaction with Reaction with
  Reaction with
• Oxygen Water Acid
• potassium Violent reaction
• sodium Burn brightly in cold water
• calcium when heated Slow reaction
• magnesium in cold water
• aluminium
• carbon Reacts with
• zinc React slowly steam not water
• iron when heated to form oxide
• tin
• lead
• hydrogen No reaction
• copper with water or
• silver No reaction steam
• gold when heated

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Reactivity Series

• Element Reaction with Reaction with
  Reaction with
• Oxygen Water Acid
• potassium Violent reaction Violent
• sodium Burn brightly in cold water
  reaction/ very
• calcium when heated Slow reaction
  dangerous
• magnesium in cold water
• aluminium
• carbon Reacts with Moderate
• zinc React slowly steam not water
  reaction
• iron when heated to form oxide
• tin
• lead
• hydrogen No reaction
• copper with water or
• silver No reaction steam No
  reaction
• gold when heated

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Displacement Reactions

• These are reactions where metals high in the
  Reactivity Series displace metals lower in the
  series from their compounds.
• Example 1
• iron copper iron
  copper
• sulphate sulphate
• solution solution

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Displacement reactions

• iron copper iron
  copper
• sulphate sulphate
• solution solution
• Fe(s) CuSO4(aq) FeSO4(aq)
  Cu(s)
• Example 2
• zinc iron(II)
• nitrate
• solution

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Displacement Reactions

• zinc iron(II) zinc
  iron
• nitrate nitrate
• solution solution
• Zn(s) Fe(NO3)2(aq) Zn(NO3)2(aq)
  Fe(s)
• Example 3
• copper zinc
• nitrate
• solution

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Displacement Reactions

• copper zinc
• nitrate NO REACTION
• solution

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Extraction of Metals

• Ores are rocks which contain minerals (metal
  compounds) or sometimes metals, in enough
  quantities to . .
• Ores usually contain the metal in its o..
• form.
• Extraction involves removing the oxygen in a
  process called r...

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Extraction of Metals

• The method of reduction depends on the position
  of the metal in the r______ s____.
• Metals high in the series (above c_____ ) are
  extracted by e__________e.g. aluminium
• Metals in the middle of the series are extracted
  by h______with c____ e.g. iron
• Metals very low in the series _____________
• ________________e.g. gold

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Extraction of Iron
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Extraction of Iron

• Raw materials i___ o___, c_____ , l______
• Hot air blast
• Oxygen reacts with coke to form _____ ____.
• C(s) O2(g) CO2(g)
• This reacts with more coke to form ________
• _______.
• CO2(g) C(s) 2CO(g)

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Extraction of Iron

• Carbon monoxide reduces iron oxide.
• Carbon monoxide is the reducing agent.
• iron carbon iron carbon
• oxide monoxide dioxide
• Fe2O3(s) 3CO(g) 2Fe(l)
  3CO2(g)

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Extraction of Iron

• In the heat of the furnace the limestone
  decomposes to lime (calcium oxide).
• CaCO3(s) CaO(s) CO2(g)
• The lime removes the acid impurities (mainly
  sand) in the molten iron.
• The impurities are known as s______.
• CaO(s) SiO2(s) CaSiO3(l)

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Extraction of Aluminium
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Extraction of Aluminium

• Raw materials purified aluminium oxide and
• cryolite (Na3AlF6)
• Aluminium oxide is dissolved in molten cryolite.
• Electrodes are made of c_______.

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Extraction of Aluminium

• Aluminium is collected at the negative
  electrode (c_________)
• Oxygen forms at the positive electrodes (a_____).
• These electrodes often need to be replaced since
  the oxygen reacts with them forming c_______
  d_______.
• Fluorine is produced from the c______ ore.

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Purification of Copper

impure copper anode
pure copper cathode
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Purification of Copper

• Copper is easily extracted by r ________, but it
  then needs to be purified by e_________.
• The p_______ electrode is impure copper.
• At this electrode copper ions (Cu2) move into
  the solution.
• Copper ions are attracted to the n_______
  electrode to form copper atoms.
• Impurities fall to the bottom.

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Transition Metals

• These are metals listed after calcium in the
  middle of the Periodic Table e.g. copper,
• iron, nickel.
• Physical Properties
• _______ melting points
• usually dense
• conduct ___________ and ______

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Transition Metals

• Chemical Properties
• form coloured compounds e.g. copper
• 
  sulphate is blue
• have more than one ion e.g. Fe2 and Fe3

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Transition Metals

• Uses
• copper - pipes and hot water tanks because
• copper is ___________.
• electrical wiring because copper is
  
• ________________.

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Transition Metals

• Iron - saucepans because iron is __________.
• car engine blocks because iron is
• ______________________.
• mixed with carbon and small amounts
• of other metals to make steel because
• iron is able to form _________.

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Transition Metals

• Uses
• nickel - in coins because nickel forms alloys
• and is unreactive.

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The End