Calculate the Gibbs free energy for formation of C2H4. Comment on the spontaneityor otherwise of the reaction at 298K.Given 2C(s)+ 2H2(g)→C2H4(g); ∆H298K = 8Kcal.Substance So(in cal.deg-1mole-1)C(s) 1.4H2(g) 31.2C2H4(g) 52.2
Question
Calculate the Gibbs free energy for formation of C2H4. Comment on the spontaneityor otherwise of the reaction at 298K.Given 2C(s)+ 2H2(g)→C2H4(g); ∆H298K = 8Kcal.Substance So(in cal.deg-1mole-1)C(s) 1.4H2(g) 31.2C2H4(g) 52.2
Solution
To calculate the Gibbs free energy (∆G), we can use the formula:
∆G = ∆H - T∆S
where: ∆H is the change in enthalpy (heat content), T is the absolute temperature in Kelvin, and ∆S is the change in entropy (disorder).
Given: ∆H298K = 8 Kcal T = 298 K So for C(s) = 1.4 cal.deg-1mole-1 So for H2(g) = 31.2 cal.deg-1mole-1 So for C2H4(g) = 52.2 cal.deg-1mole-1
First, we need to calculate the change in entropy (∆S) for the reaction.
∆S = So (products) - So (reactants)
So, ∆S = So (C2H4) - [2So (C) + 2So (H2)]
Substitute the given values:
∆S = 52.2 - [21.4 + 231.2] = 52.2 - [2.8 + 62.4] = 52.2 - 65.2 = -13 cal.deg-1mole-1
Now, we can calculate ∆G using the formula:
∆G = ∆H - T∆S
But before that, we need to convert ∆S from cal.deg-1mole-1 to Kcal.deg-1mole-1 by dividing it by 1000 (since 1 Kcal = 1000 cal). So, ∆S = -13/1000 = -0.013 Kcal.deg-1mole-1
Now, substitute the values into the formula:
∆G = 8 - 298*(-0.013) = 8 - (-3.874) = 8 + 3.874 = 11.874 Kcal
Since ∆G is positive, the reaction is not spontaneous at 298K. The reaction would be spontaneous if ∆G were negative.
Similar Questions
At 298 K, H0 = -314 kJ/mol and S0 = -0.372 kJ/(K•mol). What is the Gibbs free energy of the reaction?A.-425 kJB.0.393 kJC.34,900 kJD.-203 kJ
Which reaction shows that the enthalpy of formation of C2H4 is Hf = 52.5 kJ/mol?A.2C(s) + 2H2(g) + 52.5 kJ C2H4B.2C(s) + 4H(g) C2H4 + 52.5 kJC.2C(s) + 2H2(g) C2H4 + 52.5 kJD.2C(s) + H(g) + 52.5 kJ C2H4SUBMITarrow_backPREVIOUS
Using the following data at 298 K:Substance Df H° [kJ mol-1 ] S° [J mol-1 K -1 ]H 2 (g) 0 130.7CO (g) -110.5 197.7H 2 CO (g) -108.6 218.8(i) [2 marks]Calculate the standard Gibbs free energy change for the reaction at 298 K:H 2 (g) + CO (g) ® H 2 CO (g)
The cell in which the following reaction occurs has at 298 K. The standard Gibbs energy will be
Using Hess’s Law, determine the enthalpy of reaction for,C2H4(g) + H2(g) –> C2H6(g) ΔH = ?Using the following reactions:C2H4(g) + 3O2(g) –> 2CO2(g) + 2H2O(l) ΔH = -1401 kJC2H6(g) + 7/2O2(g) –> 2CO2(g) + 3H2O(l) ΔH = -1550 kJH2(g) + 1/2O2(g) –> H2O(l) ΔH = -286 kJGroup of answer choices243 kJ-311 kJ95 kJ-137 kJ
Upgrade your grade with Knowee
Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.