Hydrogen – the first element of the table of Mendeleyev, colourless gas. In the nature there is in the form of three isotopes, a most widespread of them – protium. It is widely applied in the different fields of the industry and also as a component of rocket fuel. It is very perspective also as automobile fuel as products of combustion of hydrogen do not do harm to the environment. Often there is a need to define what volume of hydrogen will be required for reaction with any given substance. How it can be done?
Instruction
1. You are faced by the following task: how many liters of hydrogen are required to carry out hydrogenation of 20 liters of ethylene? That is, to carry out reaction: C2H4 + H2 = C2H6. Draw a conclusion: both ethylene, and hydrogen – gases. Proceeding from the equation of reaction and Avogadro's law you will see that volumes of the reacted gases in this case are proportional to their quantities. Therefore, the required volume of hydrogen same, as well as ethylene volume, is also equal to twenty liters.
2. Or: determine what volume of hydrogen it will be emitted in interaction of 2.23 grams of sodium a lot of hydrochloric acid? You see that acid is taken much, so reaction took place up to the end, that is all amount of sodium, with formation of salt – sodium chloride – and hydrogen replacement was spent. Write down the reaction equation as follows: 2Na + 2HCl = 2NaCl + H2
3. Proceeding from coefficients and also from what 2.23 grams of sodium make 0.1 asking this substance, draw a conclusion: it was allocated 0.05 asking hydrogen. As, according to Avogadro's law, under normal conditions one mol of gas occupies 22.4 liters, receive the answer: 22.4 * 0.05 = 1.12 liters
4. Find the volume occupied by hydrogen, knowing its weight. Here you will be come to the rescue by the universal equation of Mendeleyev – Klapeyrona, the describing condition of ideal gas. Certainly, hydrogen is not ideal gas, but at temperatures and pressure which are not too differing from normal, use this equation in calculations. Write down it as follows: PVm = MRT
5. By elementary transformation, you receive the necessary formula: V = MRT/Pm, where M – the mass of hydrogen known to us, R – a universal gas constant, T – temperature in degrees Kelvin, P – pressure in pascals, m – the molar mass of hydrogen.
6. Substituting sizes known to you in a formula, receive required result.