Types of inorganic compounds

Objectives

1. To consider the range of different types of inorganic compounds

2. To learn how to name them!Outcomes

1. To be able to list the different types of inorganic compounds and list some of their key features

Main types of inorganic compound

1. Acids2. Oxo acids;3. Hydroxides4. Metal oxides5. Non metal oxides6. Binary salts and those containing

polyatomic ions7. Peroxides

Acids

These are compounds that dissolve in water to release Hydrogen ions H+ also called protons because a hydrogen ion has lost its one electron and there are no neutrons in the Hydrogen nucleus.

Strong acids release high concentrations of hydrogen ions – weak acids release low concentrations of hydrogen ions.

Simple acids comprise Hydrogen plus another non/metal such as chlorine (HCl)

Such acids are named following these rules Name always starts with hydro The anion name is changed from ide to ic So HCl is hydrochloric acid What would we call HF What would we call HI

Oxoacids

These are all acids that contain both a hydrogen ion and an anion containing oxygen.

Examples are sulphuric and nitric acid:H2SO4 HNO3

These are formed when the oxides of sulphur and nitrogen dissolve in water.

The oxides of sulphur and nitrogen are gases and covalent molecules.

They become ions when dissolved.Oxo acids are named differentlyThe main form is named after the other element in the

anion (not the oxygen) and the name ends in ic

Oxoacids continued

If it has one more oxygen than the normal ic form then it has the prefix per added

E.g.Chloric acid is HCLO3

Add another oxygen and you get perchloric acid: HCLO4

Oxo acids continued

If there are less oxygens than the ic form then you add the suffix ous

E.g. Sulphuric acid is H2SO4

Sulphurous acid is H2SO3

Nitric acid is HNO3

Nitrous acid is ……2 fewer and you also add the prefix hypoE.g. hypochlorous acid: HClO

Main lab acids

HCl HydrochloricH2SO4 Sulphuric acidHNO3 Nitric acid

You must learn these three off by heart – no excuses!

3. Hydroxides

These are bases that dissociate into metal and hydroxyl (OH)- ions when dissolved in water;

Hydroxyl ions have as you can see a valency of -1.pH of solution is always alkaline (more than 7)Most formed by group 1 and 2 metals, but others

can be formed such as Aluminium and Iron (III) hydroxide.

Most are highly soluble, whilst some like iron (iii) are not.

Hydroxides continued

Strong alkalis are very corrosive of organic tissue;

Feel and taste soapyStrong bases e.g. NaOH dissociate almost

completely in water: NaOH (s) dissolved in water Na+

(aq)+ OH-(aq)

Almost no NaOH remains.

Hydroxides continued

Weak bases such as ammonia (NH3) do form weak alkalis, but much of the ammonia remains as undissociated molecules rather than accepting a hydrogen ion to become ammonium (NH4)+ (Double arrow shows that reaction is constantly going in both directions.

NH3 (g) + H2O (NH4)+(aq) + OH-

(aq)

Hydroxides continued

Neutralise acids – OH- react with H+ ions in a ratio of 1:1 to produce water.

Acid + alkali salt + water (remember this!!)

Hydroxides used in soap manufacture, detergents, cleaners, solutions for unblocking drains and antacids

Metal oxides

Often known as basesFormed by burning metals in air, or by natural

oxidation which results in the corrosion of metals;

Most metals react with oxygen to form oxides, though some such as gold do not.

Oxygen has a valency of 2 so it is easy to work out the formulae if you know the valency of the metal

Oxidation of many metals is also known as corrosion or in the case of iron, rusting!

Work out the formulae of these

Lithium oxide

Copper (i) oxide

Silver (ii) oxide

Tin (iv) oxide

Beryllium oxide

Non-metal oxides

These tend to be gases, e.g. sulphur dioxide, carbon dioxide, and the various nitrous oxides. They are found in exhaust gases and are an important part of air pollution.

When dissolved in water they form acids (oxo acids)This leads to acid rain.The strength of the oxo acid depends on how readily

they dissociate into their ions. Sulphur dioxide readily dissociates to form sulphuric and sulphurous acids which are very strong acids.

Carbon dioxide only slightly dissociates to form carbonic acid which is very weak.

Salts

Do not get confused. Table salt is only one of manySalts are made of a metal and a non metalThey are of course ionic compoundsThose containing simply a metal and one type of non

metal as a cation and anion are called binary salts.Those such as sulphates with polyatomic anions

containing oxygen are referred to as oxisales in spanish. No direct translation of this has been found by me as yet. (oxisalts?). Do we really need to distinguish??

They have variable solubilities: copper sulphate is very soluble, calcium carbonate (chalk and limestone is only very slightly soluble)

Salts continued

If dissolved in water readily conduct an electric current

Have high melting pointsThe more reactive the constituent elements,

the more stable the salt;In solution a less reactive cation can be

replaced by a more reactive oneE.g. Copper sulphate + calcium = Calcium

sulphate + copper

Salts continued

Produced by the reactions of metals and alkalis with acids

Metal + acid = Salt + HydrogenAcid + alkali = Salt + waterAcid + carbonate = salt + carbon dioxide +

water

Acids and salts

Sulphuric acid makes sulphatesNitric acid makes nitratesCarbonic acid makes carbonatesHydrochloric acid makes chloridesSulphurous acid makes sulphitesNitrous acid makes……………………..Hydrofluoric acid makes ………………Chloric acid makes …………………….

Peroxides

Have an additional oxygenH2O2

Called hydrogen peroxideFormed in cells during metabolismStrong oxidising agentBreaks down to water and oxygenWrite the balanced equation

Your research

Find an example of each of these types of compounds which has a use or plays a role, good or bad in our lives.

1. Acids2. Oxo acids;3. Hydroxides4. Metal oxides5. Non metal oxides6. Binary salts and those containing polyatomic ions7. Peroxides

Work together in pairs.This will be your P3 exam. Submit to howard@itesm.mx

Friday afternoon.

Rubric for team report on types of compounds

1. name an example2. Give its formula3. explain it’s use or the harm it causes4. say how it is formed5. add any relevant information you can e.g

environmental impacts of its production6. reference information where it is in the text – not just

at the end. 7. Use visual information with captions8. describe chemical reactions with formulae9. Try to write in perfect English (check each other’s

spelling) 10 marks per section. 70 marks in total