1. C2 Chemistry

2. Chapters in this unit
1. Structures and bonding 2. Structures and properties 3. How much? 4. Rates of reaction 5. Energy and reactions 6. Electrolysis 7. Acids, alkalis and salts

3. 1.1 Atomic structure Type of sub-atomic particle Relative charge Mass
Proton +1 1
Neutron
Electron -1
Negligible

4. 1.1 Atomic structure Atomic number: Mass number:
The number of protons in an atom equal to the number of electrons
Mass number:
The number of protons and neutrons in the nucleus of an atom

5. 1.2 Electron Arrangement
Electrons are arranged in _____________ (also known as _______ or ________ _________ .)
The first shell can hold up to _______ electrons.
The second shell can hold up to _________ electrons.
The third shell can hold up to _________ electrons.
The Group number on the Periodic Table is the same as the _______ of _________ in the outer shell of the element.

6. 1.2 Electron Arrangement
Electrons are arranged in shells (also known as orbitals or energy levels.)
The first shell can hold up to two electrons.
The second shell can hold up to eight electrons.
The third shell can hold up to eight electrons.
The Group number on the Periodic Table is the same as the number of electrons in the outer shell of the element.

7. 1.2 Electronic Arrangement
Group 1 metals (aka alkali metals)
- Have _ _______ in outer most shell
- ____ metals, easily cut
- Reacts with _____ and oxygen
- Reactivity ______ down the group
- Low melting and boiling points

8. 1.2 Electronic Arrangement
Group 1 metals (aka alkali metals)
- Have 1 electron in outer most shell
- Soft metals, easily cut
- Reacts with water and oxygen
- Reactivity increases down the group
- Low melting and boiling points

9. 1.2 Electronic Arrangement
Group 7 halogens
- Have ___ electrons in outer most shell
Fluorine, chlorine – _____
Bromine – _____
Iodine - _____
Reactivity increases up the group
A ______ reactive halogen can displace the one ______ .
- _____ melting and boiling points

10. 1.2 Electronic Arrangement
Group 7 halogens
- Have 7 electrons in outer most shell
Fluorine, chlorine – gases
Bromine – liquid
Iodine - solid
Reactivity increases up the group
A more reactive halogen can displace the one below.
- Low melting and boiling points

11. 1.2 Electronic Arrangement
Group 0/8 (aka noble gases)
- Have _____ electrons in outer most shell (full)
- Very _____ gases, no reaction

12. 1.2 Electronic Arrangement
Group 0/8 (aka noble gases)
- Have 2/8 electrons in outer most shell (full)
- Very stable gases, no reaction

13. 1.3 Chemical Bonding Element – one _____ of atom Mixture
Easy to ________ by physical process, e.g. _______ or distillation
Compound
Chemical ______ takes place
_______ form between atoms

14. 1.3 Chemical Bonding Element – one type of atom Mixture
Easy to separate by physical process, e.g. filtering or distillation
Compound
Chemical reaction takes place
Bonds form between atoms

15. 1.4 Ionic Bonding Metal + non-metal bonding together
Group 1 element
Group 7 element
Metals lose electrons and become positive ions.
Non-metals gain electrons and become negative ions.
An ionic bond is the very strong attraction between positively and negatively charged ions

16. 1.4 Ionic Bonding (metal + non-metal)
Ionic bonds:
form a giant lattice structure
have high melting and boiling points
do not conduct electricity
UNLESS molten or in solution (when charged particles (ions) are free to move.
Link to energy required to break bonds

17. 1.5 Covalent Bonding Non-metal + non-metal bonding together
Definition: A _____ ______ of electrons
Simple molecules
Examples: water, ammonia, oxygen, nitrogen, carbon dioxide Properties: ____ melting and boiling points Weak ________________ forces. Liquid or ____ No charged particles so ___ _____ ________ electricity

18. 1.5 Covalent Bonding Non-metal + non-metal bonding together
Definition: A shared pair of electrons
Simple molecules
Examples: water, ammonia, oxygen, nitrogen, carbon dioxide Properties: Low melting and boiling points Weak intermolecular forces. Liquid or gas No charged particles so DO NOT conduct electricity
Link to energy required to overcome forces

19. 1.5 Covalent Bonding _____ structures
Non-metal + non-metal bonding together
_____ structures
Examples: ___________ , graphite, silicon dioxide (______), fullerenes
______ ______melting and boiling points Do not _______ electricity (EXCEPT _______!)

20. 1.5 Covalent bonding Giant structures
Non-metal + non-metal bonding together
Giant structures
Examples: Diamond, graphite, silicon dioxide (sand), fullerenes
Very high melting and boiling points Do not conduct electricity (EXCEPT graphite!)

21. 1.6 Bonding in Metals
Definition: ________ ions in a ‘___’ of ____________ electrons
Atoms are closely packed in a _______ arrangement
Atoms are in ______which ______ over each other easily, so can be _______ .
Properties: solid, _____ melting and boiling points, ______ _________ of heat and electricity

22. 1.6 Bonding in Metals
Definition: Positive ions in a ‘sea’ of delocalised electrons
Atoms are closely packed in a regular arrangement
Atoms are in layers which slide over each other easily, so can be shaped
Properties: solid, high melting and boiling points, good conductors of heat and electricity

23. 2.3 Graphite
A giant ________ structure which has different properties to those you would expect – so they always ask you about it somehow!
Structure:
Carbon atoms held together in layers by _____ bonds. The fourth bonding electron is _______.
________forces between layers, so layers can ______ over each other.
Properties:
The free electron from each C atom can move in between the layers, making graphite a ____ _______of electricity.
Used as a lubricant because it is ___ and layers ____.

24. 2.3 Graphite
A giant covalent structure which has different properties to those you would expect – so they always ask you about it somehow!
Structure:
Carbon atoms held together in layers by three bonds. The fourth bonding electron is delocalised.
Weak forces between layers, so layers can slide over each other.
Properties:
The free electron from each C atom can move in between the layers, making graphite a good conductor of electricity.
Used as a lubricant because it is soft and layers slide.

25. 2.5 Nanoscience Definition of a nanoparticle: 1-100 nm in size
Have different properties to same materials in bulk
Have very large surface area to volume ratio
Used in modern sun creams
Some issues about their safety and unknown effect on the body

26. 2.5 Nanoscience Titanium oxide on windows
Titanium oxide reacts with sunshine, which breaks down dirt.
Silver and socks
Silver nanoparticles in socks can prevent the fabric from smelling

27. 3.1 Mass numbers
Mass number – atomic number = number of neutrons E.g. Sodium 23 – 11 = 12
Isotopes
Same number of protons
Different number of neutrons

28. 3.2 Masses of atoms and moles
Relative atomic masses (Ar) Mass of atom compared to 12C e.g. Na = 23, Cl = 35.5 Relative formula masses (Mr) Mass of a compound found by adding Ar of each element e.g. NaCl = = 58.5
Moles
A mole of any substance always contains same number of particles
- Relative atomic mass in grams
- Relative formula mass in grams

29. 3.3 Percentages and formulae
Percentage mass % = mass of element total mass of compound Empirical formula Al Cl
Mass 9
35.5 Ar 27
Moles
(9/27) = 0.33
(35.5/35.5) = 1
Simplest ratio (divide by smallest number of moles)
(0.33 / 0.33) = 1
(1 / 0.33) = 3
Formula
AlCl3

30. 3.4 Balancing Equations H2 + O2  H2O Elements (Right-hand side)
Elements (Left-hand side)
H =
O =

31. 2NaOH + Cl2  NaOCl + NaCl + H2O
3.4 Reacting Masses
2NaOH + Cl2  NaOCl + NaCl + H2O
If we have a solution containing 100 g of sodium hydroxide, how much chlorine gas should we pass through the solution to make bleach?
(Too much, and some chlorine will be wasted, too little and not all of the sodium hydroxide will react.)

32. 2NaOH + Cl2  NaOCl + NaCl + H2O
3.4 Reacting Masses
2NaOH + Cl2  NaOCl + NaCl + H2O
100 g ?

33. 3.5 Percentage Yield
Very few chemical reactions have a yield of 100% because:
Reaction is _________
Some reactants produce _________ ______
Some products are _____ ______in apparatus
Reactants may not be completely ___
More than one product is produced and it may be ____ __ ________the product we want

34. 3.5 Percentage Yield
Very few chemical reactions have a yield of 100% because:
Reaction is reversible
Some reactants produce unexpected products
Some products are left behind in apparatus
Reactants may not be completely pure
More than one product is produced and it may be difficult to separate the product we want

35. 3.5 Percentage Yield
Percentage yield % yield = amount of product produced (g) x 100% max. amount of product possible (g)

36. A + B C + D = reversible reaction
3.6 Reversible Reactions
A + B C + D = reversible reaction

37. 4.7 Energy and reversible reactions
Hydrated Anhydrous copper sulphate copper sulphate + water
_________ reaction
Endothermic reaction

38. 4.7 Energy and reversible reactions
Hydrated Anhydrous copper sulphate copper sulphate + water
Exothermic reaction
Endothermic reaction

39. 4.7 Energy Changes Exothermic reaction, e.g. respiration
Energy ‘exits’ reaction – gives _____
out to _________
Thermometer readings ______
Endothermic reaction, e.g. photosynthesis
Energy ‘enters’ reaction – ______heat ___ ____surroundings
Thermometer readings ____

40. 4.7 Energy Changes Exothermic reaction, e.g. respiration
Energy ‘exits’ reaction – gives heat
out to surroundings
Thermometer readings rises
Endothermic reaction, e.g. photosynthesis
Energy ‘enters’ reaction – takes heat in from surroundings
Thermometer readings fall

41. 3.7 Analysis
Chemists use analysis to find out ______ (qualitative) and ____ _____(quantitative) of a substance is in something, e.g., analysing blood or urine samples for ______ , _______ analysis, etc. Chromatography is used to _______ compounds in a mixture, e.g, felt tip pens or food colourings. The _____ of spots indicates how many colours there are and which are the _____.

42. 3.7 Analysis
Chemists use analysis to find out what (qualitative) and how much (quantitative) of a substance is in something, e.g., analysing blood or urine samples for doping, forensic analysis, etc. Chromatography is used to separate compounds in a mixture, e.g, felt tip pens or food colourings. The number of spots indicates how many colours there are and which are the same.

43. 3.7 Instrumental Analysis
It is _____, more ______ and smaller samples can be analysed using an instrumental method such as _____ . Disadvantages are that it is ________ and requires special ______. The compounds are _________ using the Gas Chromatograph and then ____________ using the Mass Spectrometer, which tells us the _______ ____and therefore what the unknown substance is.

44. 3.7 Instrumental Analysis
It is faster, more accurate and smaller samples can be analysed using an instrumental method such as GC-MS. Disadvantages are that it is expensive and requires special training. The compounds are SEPARATED using the Gas Chromatograph and then IDENTIFIED using the Mass Spectrometer, which tells us the molecular mass and therefore what the unknown substance is.

45. 4.2 Collision Theory Collision theory
Chemical reactions only occur when _______ ______-collide with each other with _____ ______. The minimum amount of energy is called the _________ _______ .
Rate of reaction increases if:
temperature ________
concentration or pressure __________
surface area ________
_________ used

46. 4.2 Collision Theory Collision theory
Chemical reactions only occur when reacting particles collide with each other with sufficient energy. The minimum amount of energy is called the activation energy
Rate of reaction increases if:
temperature increases
concentration or pressure increases
surface area increases
catalyst used

47. 4.2 Surface Area
Why? The inside of a large piece of solid is not in contact with the solution it is reacting with, so it cannot react. How? Chop up solid reactant into smaller pieces or crush into a powder This increases surface area, so there is more chance of collision.

48. 4.3 Temperature
Why? At lower temperatures, particles will collide: a) less often b) with less energy How? Particles gain energy and move faster. There are more successful collisions (i.e. collisions where particles have energy greater than activation energy) Increasing the temperature by 10oC will double the rate of reaction.

49. 4.4 Concentration
Why? Concentration is a measure of how many particles are in a solution. Units = mol/dm3 The lower the concentration, the fewer reacting particles, so the fewer successful collisions there will be. How? Add more reactant to the same volume of solution. This means there will be more particles, so more collision.

50. 4.4 Pressure
Why? Pressure is used to describe particles in gases The lower the pressure, the fewer successful collisions How? Decrease the volume or increase the temperature This forces the particles to be closer together and so there will be more collisions.

51. 4.5 Catalysts
Why? It is expensive to increase temperature or pressure so we may choose to use a catalyst. Catalysts do not get used up in reaction and can be reused. How? Catalysts are made from transition metals, e.g. iron, nickel, platinum They provide surface area for reacting particles to come together and lower activation energy.

52. 6.1 Electrolysis
Electrolysis: _______ __ using __________ . Ionic substance - _______(l), or - _________ (aq)
Non-metal ion
Metal ion

53. 6.1 Electrolysis
Electrolysis: splitting up using electricity Ionic substance - molten (l), or - dissolved (aq)
Non-metal ion
Metal ion

54. 6.2 Changes at the Electrodes
Solutions Water contains the ions: H+ and O2- The less reactive element will be given off at electrode.
Oxidation is loss
Reduction is gain
OIL
RIG
Molten (PbBr)
2Br-  Br2 + 2e-
Pb2+ + 2e-  Pb
Solution (KBr)
2H+ + 2e-  H2

55. 6.3 Electrolysis of Brine At anode 2Cl- (aq)  Cl2 (g) + 2e-
At cathode
2H+ (aq) + 2e-  H2 (g)
In solution
Na+ and OH-

56. 6.4 Purifying Copper At anode 2H2O (l)  4H+ (aq) + O2 (g) + 2e-
At cathode
Cu2+ (aq) + 2e-  Cu (s)

57. 7.1 Acids and Alkalis
Acids = H+ ions Alkalis = OH- ions Alkalis = soluble bases

58. 7.2 + 7.3 Salts Acid Formula Salt Example __________ HCl Chloride
Sodium _______
Sulphuric
H2SO4
_____
Copper _______
_______
HNO3
______
Potassium _____

59. 7.2 + 7.3 Salts Acid Formula Salt Example Hydrochloric HCl Chloride
Sodium Chloride
Sulphuric
H2SO4
Sulphate
Copper Sulphate
Nitric
HNO3
Nitrate
Potassium Nitrate

60. 7.2 + 7.3 Salts: metals, bases and alkalis
Metals: Metal(s) + _____(aq)  salt(aq) + _______(g) Bases: ____(aq) + base(aq)  ___(aq) + ____(l) Alkalis: Acid(aq) + alkali(aq)  salt(aq) + water(l) Ionic equation (________): H+ + OH-  _____

61. 7.2 + 7.3 Salts: metals, bases and alkalis
Metals: Metal(s) + acid(aq)  salt(aq) + hydrogen(g) Bases: Acid(aq) + base(aq)  salt(aq) + water(l) Alkalis: Acid(aq) + alkali(aq)  salt(aq) + water(l) Ionic equation (neutralisation): H+ + OH-  H2O

62. 7.3 Salts: solutions
Making salts from Solutions: solution(_ )+ solution(_)  precipitate(_) + solution(_) Solid precipitate is ______ off and _____. Examples: Lead nitrate + potassium iodide  lead iodide(s) + potassium nitrate(aq)

63. 7.3 Salts: solutions
Making insoluble salts from Solutions: solution(aq) + solution(aq)  precipitate(s) + solution(aq) Solid precipitate is filtered off and dried. Examples: Lead nitrate + potassium iodide  lead iodide(s) + potassium nitrate(aq)