Gay Lussac’s of combining volumes states that gases react in simple ratio with one another and to volumes of the products provided that temperature and pressure remain constant. In this article, you will understand how to apply this law in calculation by studying the following examples below: 1. 2H 2 + O 2 → H 2 O In the reaction above, what volume of hydrogen would be left over when 300cm 3 of oxygen and hydrogen are exploded in a sealed tube? 1cm 3 of oxygen = 2cm 3 of hydrogen 300cm 3 of oxygen = 2 x 300 = 600cm 3 Volume of left over = 1000 – 600 = 400cm 3 2. Calculate the volume of carbon (II) oxide required to react with 40cm 3 of oxygen. 2CO + O 2 → 2CO 2 1cm 3 of oxygen = 2cm 3 of CO 40cm 3 of oxygen = 2 x 40 = 80cm 3 3. Calculate the volume of residual gases that would be produced when 100cm 3 of sulphur (IV) oxide reacts with 20cm 3 of oxygen 2SO 2 + O 2 → 2SO 3 1cm 3 of O 2 = 2cm 3 20cm 3 of O 2 = 2 x 20 = 40cm 3
The analysis requires a good knowledge of the specific reactions of the ions with certain reagents, for example an unknown solution which contains copper ions will give a deep blue solution with excess ammonia solution. Related post Qualitative analysis of copper(II)tetraoxosulphate VI So what we are going do here is to identify these ions using their specific reactions. A mixture of calcium chloride and iron (II) tetraoxosulphate (VI) will undergo a double decomposition reaction to yield calcium tetraoxosulphate (VI) and iron (II) chloride. CaCl 2 (aq) + FeSO 4 (aq) --------- FeCl 2(aq) + CaSO 4(s) Since calcium tetraoxosulphate (VI) is insoluble, iron(II)chloride can easily be filtered off with filter paper or by any other means possible. How to identify the Cations in the mixture Cations are positive charged ions. We have two of these types of ions in the mixture which · Iron (II) ions · Calcium ions How to identify Iron (II) ions A