Exam revision 1: Basic oxides and water treatment.

I sat down last night to complete an entry for you, but the words just weren’t coming out right so I gave up. 

Attempt 2:

I had a look at the subject outline and tried to guess which part you are most likely to overlook in your revision. This is the part that I picked out for you:

The trend from metallic to non-metallic behaviour across a period is related to the increase in electronegativity. These trends are reflected in changes in the acidic/basic character of the oxides.

The oxides of non-metals are acidic. Their acidic character can be displayed by reaction with hydroxide ions to produce an oxyanion and, in most cases, by reaction with water to produce an oxyacid.

The oxides of metals are basic. Their basic character can be displayed by reaction with an acid to produce a cation and, in some cases, by reaction with water to produce OH- in solution.

Metalloids form amphoteric oxides. Amphoteric oxides can display basic character by reaction with hydrogen ions and acidic character by reaction with hydroxide ions.

You were all fairly good at this when we learnt it earlier in the year.

To summarise:

Acidic oxides react with bases and with water. Some of the equations for reactions with water are shown below:

Basic oxides react with acids and with water.

Amphoteric oxides react with both an acid and a base.  Examples include zinc oxide and aluminium oxide.

You need to know how to write the corresponding equations.  You can find a nice summary table for these in your Essentials p13 and14.

Further information can be located here.

From the same website, a partial summary for water treatment can also be located.


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