Chemical Changes

1) What are Chemicals ?
This is the name given to substances that are used in a chemical reaction
Chemicals is another word for substances
The chemicals you start with are called the reactants
The chemicals you finish with are called the products
Chemical formulas are used to indicate what is happening in a chemical reaction
These chemical formulas are called symbol equations.

2) What is a Chemical Reaction ?
This is a process in which one or more substances are converted into one or more different substances.

3) Can you describe what happens in a chemical reaction ?
atoms are not changed or destroyed
atoms move around
the mass does not change (the products weigh the same as the reactants)
there is always a transfer of energy to or from the surroundings

4) What is a Chemical Equation ?
This is a way to show a chemical reaction using letters and numbers.

5) What is an Ionic Equation ?
This is a chemical equation that shows the specific particles - such as dissolved ions or molecules - that actually take part in a reaction

6) What is an Ore ?
A natural rock containing valuable minerals with metals and metal compounds.

7) Can you name the four factors that affect the rate of reaction ?
Temperature
Surface Area
Concentration / Pressure
Any Catalysts

8) How many different types of reactions are there ?
Oxidation
Reduction
Neutralisation
Displacement - A more reactive metal forms stronger bonds with non-metals.
Combination / Synthesis
Thermal Decomposition - this is when a substance is heated and breaks down

9) How can metals be extracted ?
Electrolysis
Photomining
Bioleaching
Reduction
Displacement

10) What is a Oxidation Reaction ?
This is when a metal reactions with oxygen to produce a metal oxide.
Gaining oxygen, losing electrons.
Combustion is an oxidation reaction

11) Can you give some examples of oxidation reactions ?
Rust - Iron + Oxygen = Iron Oxide

12) What is a Reduction Reaction ?
Losing oxygen, gaining electrons

13) Can you give some examples of reduction reactions ?
2CuO + C = 2Cu + CO2
where Cu = (Cu2 + 2e- = Cu)

14) What is a Redox Reaction ?
REDuction and OXidation happen at the same time (REDOX)
If electrons are transferred, its a redox reaction.

15) What is a Displacement Reaction ?
When a metal or the element Carbon (C) comes into contact with a metal in a compound that is lower in the reactivity series there will be a reaction.
A more reactive metal displaces a less reactive metal.

16) Can you give some examples of displacement reactions ?

Iron + Copper Sulfate = Iron Sulfate + Copper

Fe(s) + CuSO4(aq) = FeSo4(aq) + Cu(s)

Carbon + Iron(III) Oxide = Carbon Dioxide + Iron

3C(s) + 2Fe2O3(s) = 3CO2(g) + 4Fe(l)

Carbon + Zinc Oxide =

C + 2ZnO = CO2 + 2Zn

Zinc + Copper Sulfate = Zinc Sulfate + Copper

17) What is a Neutralisation Reaction ?
When an acid and a base are mixed together, they react
If an acid is reacted with a base then salt and water is created and its PH will be 7.
This process is called neutralisation.

18) Can you give some examples of neutralisation reactions ?
acid + metal oxide = salt + water
acid + metal hydroxide = salt + water
acid + metal carbonate = salt + water + carbon dioxide

19) What is a Combination / Synthesis reaction ?

20) Can you give some examples of combination / synthesis reactions ?

Sodium + Hydrogen = Sodium Hydride

Hydrogen + Oxygen = Water

Hydrogen + Carbon = Methane Gas

Sodium + Titanium Chloride = Sodium Chloride + Titanium

Na + TiCl4 = NaCl2 + Ti (?)

Sodium + Chlorine = Sodium Chlorine

Sodium + Chloride = Sodium Chloride

Na+ + Cl = NaCl

Aluminium + Copper Chloride = Aluminium Chloride + Copper

2Al + 3CuCl2 = 2AlCl3 + 3Cu

21) What are SALTS ?
Do not confuse this with Table Salt (NaCl = sodium chloride)
"salts" is a broad family name for any ionic compound made from positive and negative ions.
Sodium chloride is just one type of salt. Not all salts contain sodium chloride.

22) What is Table Salt ?
Table salt is 97% to 99.9% pure sodium chloride (NaCl)

23) What is the difference between Table Salt and Sea Salt ?
Sea salt has tiny amounts of extra minerals like magnesium and potassium.
Table salt is heavily processed, mixed with anti-caking agents, and fortified with iodine.

24) What is the difference between Table Salt and Epson Salt ?
These are completely different chemical compounds with different molecular structures, tastes, and uses.
Table salt is sodium chloride (NaCl)
Epsom salt is magnesium sulfate (MgSO4 7H2O)

25) Can you give a list of the different types of SALTS ?
Sulfate Salts - Copper sulfate, Calcium sulfate
Chloride Salts - Potassium chloride
Nitrate Salts - Potassium nitrate, Silver nitrate
Carbonate Salts - Calcium carbonate, Sodium bicarbonate

26) Can you describe these different types of substances ?
Base - a substance that reacts with an acid
Neutral - a substance that makes a solution with a PH=7
SALT - a substance made in a neutralisation reaction
Alkali - a substance that reacts with an acid that can dissolve in water to make a solution with a PH>7
Acid - a substance that contains hydrogen and can dissolve in water to make a solution with PH<7

27) Can you give some examples of metals with oxygen ?
These reactions produce metal axides and are called oxidation

Oxygen + Iron = Iron Oxide (rust)

Oxygen + Potassium =

Oxygen + Sodium =

Oxygen + Magnesium = Magnesium Oxide

O2 + 2Mg = 2MgO

Oxygen + Copper = Copper Oxide

O2 + Cu = CuO

28) Can you give some examples of metals with water ?
form metal hydroxide and hydrogen gas

Water + Potassium =  Potassium Hydroxide + Hydrogen

2K + 2H2O = 2KOH + H2

Water + Calcium = Calcium Hydroxide + Hydrogen

29) What is an Acid ?
An acid is a substance that forms an aqueous solution with a pH of less than 7.
Acids must dissolve in water to release hydrogen ions.
For example: Without water, hydrogen chloride is just a neutral gas.
It only becomes hydrochloric acid when water allows the ions to break free.

30) What is an Alkali ?
An alkali is a substance that forms an aqueous solution with a pH of more than 7.
Alkalis must dissolve in water to release hydroxide ions.
For example: Without water sodium hydroxide in its solid state is a BASE, but if dissolves in water it becomes a strong alkali.
The release of the hydroxide ions is what makes the solution alkaline.

31) What is a Strong Acid ?
These ionise completely in water.
All the acid particles dissolve to release H+ ions
examples are: Sulfuric, Hydrochloric, Nitric

H C l = H^{+} + C l^{-}

32) What is a Weak Acid ?
These do not ionise fully in the solution
Only a small proportion of acid particles dissociate to release H= ions
examples are: Carbonic, Citric, Ethanoic

C H_{3} C O O H = H^{+} + C H_{3} C O O^{-}

33) How can you make Hydrochloric Acid ?
Hydrogen Chloride + Water = Hydrochloric Acid

34) What are Metal Carbonates ?

35) What is a Carbonic Acid solution ?

36) Can you give some examples of metals with acid ?
These reactions produce salt and hydrogen gas

Sulfuric Acid + Zinc =

H2SO4 + Zn = ZnSO4 + H2

Sulfuric Acid + Iron =

Hydrochloric Acid + Zinc = Zinc Chloride + Hydrogen

Hydrochloric Acid + Sodium = Sodium Chloride + Hydrogen

Hydrochloric Acid + Magnesium = Chloride + Hydrogen

2HCl + Mg = 2MgCl2 + H2

37) Can you give some examples of carbonates with acid ?
These reactions ..

Copper Carbonate + Sulfuric Acid =

38) What is an Base ?
A base is any substance that will react with an acid to form a salt.

39) Can you give some examples of bases
Sodium Hydroxide (soluble)
All metal hydroxides are bases.

40) Can you give some examples of bases and acid ?
These reactions ..

Nitric Acid + Potassium Hydroxide = Salt + Water

Nitric Acid + Copper Hydroxide = ? + ?

Hydrochloric Acid + Copper Oxide = Copper Chloride + Water

41) How can you measure the PH of a solution ?

42) What is the Reactivity Series ?
A list of metals in order of reactivity.
Potassium (K)
Sodium (Na)
Lithium (Li)
Calcium (Ca)
Magnesium (Mg)
Aluminimum (Al)
Carbon (C) (GAS)
Zinc (Zn)
Iron (Fe)
Tin (Sn)
Lead (Pb)
Hydrogen (H) (GAS)
Copper (Cu)
Silver (Ag)
Gold (Au)
Platinum (Pt)

43) Is Chlorine on the periodic table ?

44) In the Reactivity Series which metals react with Acid
The more reactive a metal is, the more vigorous the reactions with acid and water are, and the more the temperature increases.
metals above hydrogen

45) Why do metals conduct electricity ?
Delocalised electrons can move freely and carry charge

46) What are Reacting Volumes ?

47) What is Titration ?

48) What is the Haber Process ?
It produces Ammonia from Nitrogen and Hydrogen

49) What is Electrolysis ?
At the negative electrode positively charged ions gain electrons.

50) What is an Exothermic Reaction ?
This is a chemical reaction that transfers energy to the surroundings
rusting, camp fires, water evaporation, water + acid reacting, nuclear fusion

51) What is an Endothermic Reaction ?
This is a chemical reaction that takes energy from the surroundings
water to ice, cooking an egg, photosynthesis, dissolving salt in water, baking bread

52) What is the name of the scale used to measure how Acid or Alkaline a substance is ?
The PH scale (from 0 to 14)
Substances with a PH less than 7 are called acids (hydrochloric acid)
Substances with a PH more than 7 are called alkaline (sodium hydroxide)
Substances with a PH equal to 7 are considered neutral (water)

53) What is an Enzyme ?
This is a biological catalyst

Questions

54) What is the difference between Chloride and Chlorine ?
Chloride is formed from chlorine.
Chloride is what is created when Chlorine gains an electron and combines with other elements

55) What is a Carbonate ?
A carbonate is a salt of carbonic acid,
Carbonates are compounds containing CO32 ions.
Carbonates react with dilute acids to form a salt, carbon dioxide, and water.
example - calcium carbonate + hydrochloric acid = calcium chloride + carbon dioxide + water
example - copper2 carbonate = copper2 oxide + carbon dioxide

56) Do all substances contain protons ?
Yes. Every element in the periodic table contains at least one proton.
The atomic number tells you how many protons.

57) Are all substances either Acid, Alkali or Neutral ?
Yes, when dissolved in water, all aqueous solutions are classified as acidic, alkaline (basic), or neutral on the pH scale.
However, this only applies to solutions or substances that can interact with water.
Many solid materials and pure chemical compounds do not fit neatly into these categories until they are placed in a liquid solvent.

58) What happens when you mix an acid with an alkali ?
Hydrogen ions from the acid react with the hydroxide ions from the alkali to make water.

59) Do all Acids contain Hydrogen ions ?
A hydrogen ion is a proton

60) Do all Alkalis contain Hydroxide ions ?
No, but they all produce Hydroxide Ions when dissolved in water.
The most common alkalis are metal hydroxides
Amonia (NH3) is an alkali that does not have hydroxide in its formula.

61) What name is given to bases that dissolve in water ?
Alkalis

62) Will an insoluable base react with an acid ?
True

63) Can all the different types of metals be found in the ground ?
False.

64) How can solid salt be obtained from a salt solution ?
By Crystallation of the salt solution.

65) What is the chemical formula for the oxidation of iron ?
Fe + CUSO4 = FeSO4 + Cu