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
Work ; This is the product of force and the displacement in the direction of the force. Work done = force x distance moved in the direction of force The unit of work done is Joule (J) How to Calculate Work Done Example Questions 1. If a car of mass 80kg moved a distance of 5m. calculate the work done by the car (g =10m/s 2 ) Solution Mass = 80kg Force = 80 x 10 = 800N Distance = 5m Work done = 800 x 5 = 4000J 2. A boy pulls a load of 300N to a distance of 6m. Calculate the work done Solution Force = 300N Distance = 6m Work done = 300 X 6 = 1800J Energy : This is the ability to do work. It is also measured in Joule (J). Energy has many forms which include: · Heat energy · Light energy · Chemical energy · Electrical energy · Atomic energy · Solar energy · Mechanical energy We are going to be studying mechanical energy. Mechanical energy is divided i