Question

Condsider the following reacton at 0C S(s) +4NO (g)--> <--- SO2 (g) + 2N2O (g) A student places 0.025 moles of solid sulfer and 0.100 moles of nirtrogen monoxide gas in a closed 1.00 L container at 0 C for several days. Calculate the number of molecules of NO in the 1.00 L container after equilibrium is reached, givern the following thermodynamic data

S(S) NO(g) SO2(g) N20 (g)

S JK-1 31.9 211 256 220

Delta H 0.00 90.4 -297 81.6

Answer 1

S(s) + 4NO(g) -----> SO₂(g) + 2N₂O(g)

K_eqb = {[SO₂]*[N₂O]²}/{[NO]⁴}

Molar concentration = moles/volume of solution in litres

Now, delta H_rkn = 2*delta H of N₂O + delta H of SO₂ - 4*delta H of NO - delta H of S = -495.4 kJ

delta S_rkn = 2*delta S of N₂O + delta S of SO₂ - 4*delta S of NO - delta S of S = -179.9 J

Now, delta G_rkn = delta H_rkn - T*delta S_rkn = -495400 - 273*-179.9 = -446287.3 J

Now, delta G = -R*T*lnK_eqb

Since, delta G < 0 therefore the reaction is spontaneous

Thus, moles of NO left unreacted = 0