1. METALS AND METAL COMPOUNDS
In This Section We Will Be Studying The Following Topics:
Useful Metals.
Metals & Acids.
Metal Carbonates & Acids.
Metal Oxides & Acids.
Alkalis & Acids.
Balanced Equations.

2. USEFUL METALS? Fill in the blanks Metals are: Meaning. Strong
All elements have physical properties such as boiling point, melting point etc.
Elements that are metals have all or most of the following physical properties.
Metals are:
Meaning.
Strong
How difficult they are to break by stretching or crushing.
Shiny and Silvery
Clean metal is usually reflective and silvery coloured.
Hard
Flexible
Dense
Lots of metals have a high mass per unit volume. A few, like aluminium, are not very dense.
Tough
Solid
Good Heat Conductors
Heat easily travels through them.
Good Electrical Conductors
Fill in the blanks
Difficult to scratch or mark.
Bends without breaking.
Does not easily break when hit.
Not a gas or a liquid.
Electricity easily travels through them.

3. Yes and what about graphite?
USEFUL METALS?
What about mercury?
Mercury is a liquid so it is not tough, solid or strong. But, it is shiny, dense and a good conductor so it is a metal.
Yes and what about graphite?
Graphite is a very good conductor of electricity but it is brittle, a grey solid and a poor conductor of heat. In fact graphite is a non-metal.
As might be expected, non-metals tend to have the opposite properties to metals i.e. brittle, poor conductors, low density and weak. Many of them are gases e.g. chlorine and nitrogen.
One final way to confirm if a substance is a metal is to see how it reacts with other chemicals. If it reacts like a metal it probably will be a metal.

4. Metals have many uses. Modern society could not exist without metals.
USEFUL METALS?
Metals have many uses. Modern society could not exist without metals.
Copper, good conductor & flexible.
Zinc - coated iron roofing. The zinc corrodes before the iron.
Iron, strong and cheap for bridge building.
Aluminium is strong, light & a good conductor, used for overhead power cables.
Gold, used on high quality circuit boards because it does not corrode.

5. Magnesium reacts very quickly.
METALS AND ACIDS
We need to learn the meaning of two descriptions we give to acids. These are concentration and strength.
Concentration – acids can be concentrated like orange or blackcurrant squash, by adding water they can be diluted. The acids you use in your lessons are diluted.
Strength – not all acids are the same strength. We put ethanoic acid (vinegar) on our chips but we certainly would not want to put sulphuric acid on them. It is a stronger acid than ethanoic.
The speed at which metals react with dilute acids depends on the metal. For example, gold does not react at all. Here are some more examples:
Zinc reacts quickly.
Magnesium reacts very quickly.
Iron reacts slowly.

6. A salt is produced when a metal reacts with an acid.
METALS AND ACIDS
So what happens when a metal reacts with an acid? Let us look by adding zinc to sulphuric acid.
When the zinc reacts with sulphuric acid, bubbles form and a gas is produced.
When tested with a lighted splint the gas proves to be hydrogen. It has a squeaky POP when burnt.
Sulphuric acid contains hydrogen ions and sulphate ions
If hydrogen is produced the zinc has replaced it, joining to the sulphate producing zinc sulphate.
We do not see the zinc sulphate because it dissolves as it is produced.
Sulphuric Acid
Zinc
Hydrogen
Zinc Sulphate Solution
Zinc sulphate is known as a Salt.
A salt is produced when a metal reacts with an acid.

7. METAL CARBONATES AND ACIDS
What is a metal carbonate?
The clue is in the name. A metal carbonate is a compound in which a metal element is joined to a carbonate group. Calcium carbonate is one of these compounds.
What is a carbonate?
Any group of atoms with ‘ate’ in the name contain oxygen. So a carbonate group contains 1 atom of carbon and 3 atoms of oxygen.
Metal carbonates are opposite to acids, they are bases. Remember alkalis are bases that dissolve in water.
Acids
Bases
Alkalis
All Substances
Alkalis are part of the Bases group of substances.

8. METAL CARBONATES AND ACIDS
There are three products from the reaction of metal carbonates with acids. Do you have any idea what they may be?
Let’s have a look at the reaction.
Calcium carbonate
Hydrochloric acid
Carbon dioxide
Calcium chloride solution
We know a reaction is taking place because a gas is produced. Testing with limewater shows that the gas is carbon dioxide. Evaporating the water would leave a salt. Finally, any spare hydrogen and oxygen atoms would have joined to make some of the water.

9. METAL CARBONATES AND ACIDS
We can write a general equation for the reaction of metal carbonates with acid:
metal carbonate + acid → a salt + carbon dioxide + water
Knowing the name of the carbonate and acid we can work out the name of the salt.
The ‘metal’ part of the name comes from the metal in the metal carbonate.
zinc carbonate + acid → zinc ???? + carbon dioxide + water
The second half of the name comes from the acid:
Sulphuric acid the ‘uric’ becomes an ‘ate’ so we get zinc sulphate.
Nitric acid the ‘ic’ becomes an ‘ate’ so we get zinc nitrate.
As we have seen hydrochloric acid is slightly different, the ‘hydro’ disappears and the ‘c’ at the end becomes a ‘de’ so we get zinc chloride.
From sulphuric acid we get sulphate salts.
From nitric acid we get nitrate salts.
From hydrochloric acid we get chloride salts.

10. METAL OXIDES AND ACIDS
Firstly, a metal oxide is a compound containing metal and oxygen atoms. For example, copper oxide – CuO. They are bases and so they react with acids.
For example, black copper oxide reacts with sulphuric acid to produce a blue solution; water is produced and a salt. The salt is copper sulphate.
copper oxide + sulphuric acid → copper sulphate + water
Crystals of copper sulphate can be produced by evaporating water from a solution of copper sulphate. The concentrated solution is left to cool and crystals form. This is crystallisation.
Copper sulphate solution.
Heat.
Concentrated solution.
Cool.

11. ALKALIS AND ACIDS
As we saw earlier, alkalis are bases that are soluble in water. Examples of alkalis are potassium hydroxide and sodium hydroxide.
The hydroxide group contains a hydrogen atom and an oxygen joined closely together. This gives the formula OH for the hydroxide group.
Potassium Hydroxide = KOH & Sodium Hydroxide = NaOH
Actually alkalis are more dangerous than acids. Household bleach is possibly the most dangerous chemical used in the home. Alkalis react with skin and because they are ‘soapy’ they are difficult to wash off.
It is also possible to make a neutral solution i.e. one with pH7, by adding an acid to an alkali. The neutral solution is reached when an indicator, e.g. Universal Indicator, in the solution turns to the correct colour. This process is called neutralisation.
What colour is Universal Indicator at pH7?
Green

12. ALKALIS AND ACIDS A salt and water. Acid + Alkali → Salt + Water
I bet I can guess what products are made from reacting acids and alkalis.
Go on then Moley
A salt and water.
Yes, right again.
Acid + Alkali → Salt + Water
From earlier slides, we know that when sodium hydroxide reacts with hydrochloric acid the salt, sodium chloride, will be produced. The hydrogen atom left over from the acid joins the hydroxide group to make water.
Sodium Hydroxide + Hydrochloric Acid → Sodium Chloride + Water
Neutralisation reactions are used in treating insect stings, indigestion and soil treatment. Also, they are used to produce pure salts.

13. BALANCED EQUATIONS
Look at the reaction equation for iron (Fe) in hydrochloric acid:
Fe + HCl → FeCl2 + H2
If we count the atoms, we get:
1 atom Fe, 1 atom H, 1 atom Cl, (total 3 atoms)→ 1atom Fe, 2 atoms Cl, 2 atoms H, (total 5 atoms)
The equation does not balance. But if we say that 2 molecules of hydrochloric acid are needed to 1atom of iron the equation will balance:
Fe + 2HCl (total 5 atoms) → FeCl2 + H2 (total 5 atoms)
We can reverse the process. If we know that 2 atoms of potassium react with 1 molecule of sulphuric acid therefore we can work out the products and amounts which will balance the equation:
2K+ H2SO4 (total 9 atoms) → K2SO4 + H2 (total 9 atoms)
The ‘small’ numbers are fixed, as they are part of the formula of the compounds, but the ‘big’ numbers can be changed to make the equation balance.

14. BALANCED EQUATIONS 2Al + 6HCl → 2AlCl3 + 3H2
Let us try this out on a slightly more complicated equation - when aluminium reacts with hydrochloric acid:
Al + HCl → AlCl3 + H2
We need at least 3 molecules of HCl which gives us 3 atoms of hydrogen but 2 atoms of hydrogen are needed to make a molecule of the gas (H2).
This can be corrected by having 6 (3 x 2) molecules of HCl, this gives 2 lots of ‘Cl3’ and 3 molecules of H2.
Al + 6HCl → AlCl3 + 3H2
OK so far? Now, 1 atom of Al joins with 1 ’Cl3’ but we have 2 lots of ‘Cl3’. So we need 2 atoms of Al to make the equation balance.
2Al + 6HCl → 2AlCl3 + 3H2
14 atoms → 14 atoms

15. That was an interesting topic. I think I got a balanced view.
BALANCED EQUATIONS
Can you say if these equations balance and if not - can you balance them?
Mg + 2HCl → MgCl2 + H2
Balances.
H2+ O2 → H2O
2H2 + O2 → 2H2O
Na + H2SO4 → Na2SO4 + H2
2Na + H2SO4 → Na2SO4 + H2
Al+ H2SO4 → Al2(SO4)3 + H2
2Al+ 3H2SO4 → Al2(SO4)3 + 3H2
That was an interesting topic. I think I got a balanced view.

16. What have we learned?
All elements have physical properties such as boiling point, melting point etc.
Metals have many physical and chemical properties.
Because of these properties metals are very useful to use.
Acids have strength and concentration.
When a metal reacts with an acid a salt and hydrogen are produced.
Metal carbonates in acids produce a salt, carbon dioxide and water.
Metal oxides and acids produce a salt and water.
By concentrating a salt solution, crystals of the salt can be produced.
A neutral solution can be made be reacting an acid with an alkali using an indicator. Salt and water are produced.
The above reactions can all be written as chemical equations.
The numbers of atoms on each side of the equation must balance.