In: Chemistry
You wish to monitor the progress of a reaction using pressures. Suppose 17.88g N2 (28.02g/mol) and 1.328g H2 (2.016g/mol) are initially present in a 25.0L reaction vessel at 124 degrees celsius. Nitrogen and hydrogen can react to form ammonia (17.04g/mol) according to the reaction shown. At a given point, the total pressure (the sume of N2, H2 and Nh3 present) is 1.62atm. What percentage of the initial N2 has reacted?
N2 (g) + 3 H2 (g) -------> 2 NH3 (g)
initially for N2 = 17.88/28.02 = 0.6381 moles
initial pressure of N2, PV = nRT
P * 25 = 0.6381 * 0.0821 * (124+273)
P = 0.8391 atm
initially for H2 = 1.328/2.016 = 0.6587 moles
initial pressure of H2, PV = nRT
P * 25 = 0.6587 * 0.0821 * (124+273)
P = 0.8588 atm
N2 (g) + 3 H2 (g) -------> 2 NH3 (g)
initially 0.8391 0.8588 0
at equi (0.8391 - x) (0.8588-3x) 2x
But it is given,
(0.8391 - x)+(0.8588-3x)+2x = 1.62
x = 0.03895
Percentage of N2 reacted = 0.03895/0.08391*100 = 46.42%