For help on analysis, try this link to another section of the Revision World site.

http://www.revisionworld.co.uk/gcse-revision/chemistry/classifying-materials/chemical-analysis

If you have 11 electrons to deal with (like sodium): 2,8,1
If you have 19 electrons (like potassium) to deal with: 2,8,8,1
The “1” in the outside shell is common to all of Group I.

The alkali metals (NOT alkaline) are all part of Group I.
They are fairly soft metals (can be cut with a knife)
They get softer as you go down the group.
The melting point decreases as you go down the group.
The reactivity increases as you go down the group.
They all react with water to give hydrogen and the metal hydroxide.

The idea is to find out the concentration of one solution if we know the concentration of the other. We need to know the volume of each solution that just rreacts together exactly with none of either left over.

 You can do the calculation using moles (see next sheet).

If we know that the ratio of acid to alkali is 1:1 we can simply use:

Concentration of A x Volume of A = Concentration of B x Volume of B

The idea is to find out the concentration of one solution if we know the concentration of the other. We need to know the volume of each solution that just rreacts together exactly with none of either left over.

 You can do the calculation using moles (see next sheet).

If we know that the ratio of acid to alkali is 1:1 we can simply use:

Concentration of A x Volume of A = Concentration of B x Volume of B

A substance that changes colour depending on the pH is called an indicator.

There are two types of indicator:
Single indicators show only one colour change and are used to decide if the pH is higher or lower than a certain value. This makes them useful for titrations.
Litmus is a common one (red in acid and blue in alkali).
Methyl Orange (red in acid and orange in alkali) and Phenolphthalein (colourless in acid and purple in alkali) are two others that are often used.

A substance that changes colour depending on the pH is called an indicator.

There are two types of indicator:
Single indicators show only one colour change and are used to decide if the pH is higher or lower than a certain value. This makes them useful for titrations.
Litmus is a common one (red in acid and blue in alkali).
Methyl Orange (red in acid and orange in alkali) and Phenolphthalein (colourless in acid and purple in alkali) are two others that are often used.

Be careful to say what you mean.....Strong or Weak / Concentrated or Dilute

When you are given a drink of orange squash, most people will ask if you would like to have it strong or weak. In a chemistry sense, this is wrong. They ought to be asking whether you like it concentrated or dilute because they want to know if you want a large amount of orange squash and a little bit of water or a little squash and a lot of water.

Be careful to say what you mean.....Strong or Weak / Concentrated or Dilute

When you are given a drink of orange squash, most people will ask if you would like to have it strong or weak. In a chemistry sense, this is wrong. They ought to be asking whether you like it concentrated or dilute because they want to know if you want a large amount of orange squash and a little bit of water or a little squash and a lot of water.

The Lowry-Bronsted theory of acids and bases depends on the giving and receiving of hydrated hydrogen ions.

An H⁺ ion is a hydrogen atom that has lost an electron.
Since a hydrogen atom is only made of one proton and one electron, if it loses one electron it is just a proton!
This very small particle with a full positive charge is strongly attracted to water molecules and so we ought to talk of the “hydrated hydrogen ion” or the “hydrated proton”...H⁺_(aq) or H₃O⁺_(aq). 

The Lowry-Bronsted theory of acids and bases depends on the giving and receiving of hydrated hydrogen ions.

An H⁺ ion is a hydrogen atom that has lost an electron.
Since a hydrogen atom is only made of one proton and one electron, if it loses one electron it is just a proton!
This very small particle with a full positive charge is strongly attracted to water molecules and so we ought to talk of the “hydrated hydrogen ion” or the “hydrated proton”...H⁺_(aq) or H₃O⁺_(aq).