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1. Assuming the gases are ideal, calculate the amount of work done, in joules, f

ID: 919292 • Letter: 1

Question

1. Assuming the gases are ideal, calculate the amount of work done, in joules, for the conversion of 1.00 mole of Ni to Ni(CO)4 at 75°C in the reaction below. The value of R is 8.314 J/mol•K.

a) 1.80x10^3J b) 8.68x10^3J c) -1.80x10^3J d) -8.68x10^3J e) -494J

2. Assuming the gases are ideal, calculate the amount of work done, in joules, for the conversion of 2.00 mole of NO2 to N2O4 at 125°C in the reaction below. The value of R is 8.314 J/mol•K.

a) 1,040J b) 3,300J c) -3,300J d) 6,600J e) -1,040J

Explanation / Answer

1) Balanced chemical equation for conversion of 1.00 mole of Ni to Ni(CO)4 is

Ni(s) + 4 CO (g) -------------> Ni(CO)4 (g)

4 mol of gas 1 mol of gas

  n =   1 mol - 4 mol = -3 mol

R = 8.314 J/mol•K

T = 75°C = 75 + 273 K = 348 K

Hence,

Work done W = - nRT

= -(-3 mol) (8.314 J/mol•K) (348 K)

= + 868 J

= + 8.68 x 103 kJ

W = + 8.68 x 103 kJ

Therefore, work done = + 8.68 x 103 kJ

2)   Balanced chemical equation for conversion of 2.00 mole of NO2 to N2O4 is

2 NO2 (g) -------> N2O4 (g)

2 mol of gas 1 mol of gas

n =   1 mol - 2 mol = -1 mol

R = 8.314 J/mol•K

T = 125°C = 125 + 273 K = 398 K

Hence,

Work done W = - nRT

= -(-1 mol) (8.314 J/mol•K) (398 K)

= + 3308 J

W = + 3308 J

Therefore, work done = + 3308 J