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Pressure and Chemical Equilibrium, No (g)+ 3H2 (g) @ 2NHy, , Forward reaction: 4 mole reactant molecules > 2 mole product molecules (volume decreases), Backward reaction: 2 mole product molecules -> 4mole reactant molecules (volume increases)., , * Ina gaseous system, decrease in the'aumber of molecules helps to decrease the pressure., , * According to Le Chatliers principle, when pressure of a system at equilibrium is increased the system, will try to attain equilibrium by reducing pressure., , + Inthe manufacture of Ammonia, the forward reaction results in the decrease in the number of|, molecules. Pressure of the system is increased, the rate of forward reaction increase., , Q: In the manufacture ofammonia, why is a high pressure of 150- 300atm used?, , Ans: To increase the produetion of ammonia by increasing the rate of forward reactions., , , , Ha (g)+ ba (g) # 2H (g), In this reaction, there is no change in the moles of the reactants and the products., , > Ina reversible reaction if there is no change in the number of gaseous molecules in the reactant, and product side pressure will not have any effect on the chemical equilibrium,, , ‘Temperature and Equilibrium, No (g)+ 3H (g) @ 2NHy + Heat, , * Backward reaction is endothermic., On increasing the temperature, the system tries to reduce it by increasing the rate of endothermic, reaction, As a result the product ammonia decomposes to form Nitrogen and Hydrogen.