Need help with a problem please entropy change of UNIVERSE when 1.859 moles of C
ID: 974932 • Letter: N
Question
Need help with a problem please
entropy change of UNIVERSE when 1.859 moles of CH4(g) react under standard conditions at 298.15 is -886.00
Is this reaction reactant or product favored under standard conditions? reactant
Convert kJ to J 206.1 x 1000 = 206,1000
S surroundings = - (206,100 / 298.15) = - 691.26
214.7 + (-691.26) = - 476.56
1.859 x (-476.56) x ( 1/1 CH4) = -885.92
Since S universe is less than zero, the reaction is reactant favored
If the reaction is product favored, is it enthalpy favored, entropy favored, or favored by both enthalpy and entropy? If the reaction is reactant favored, choose 'reactant favored'.
(enthalpy, entropy, both or product favored)
Explanation / Answer
Given chemical transformation
CH4 (g) + H2O (g) ------> CO (g) + 3H2 (g)
H° = 206.1 kJ/mol = 206.1 x 1000 = 206100 J/mol
S° = 214.7 J/K and
T= 298.15 K.
Let us calculate Gibbs free energy change (G0)
Formula,
G0 = H0 -TS0
G0 = 206100 – 298.15 X 214.7
G0 = 206100 – 64012.8
G0 = +142087.2 J/mol
G0 = + 142.087 kJ/mol
Gibbs free energy change is +ve and hence reaction is favored in reverse direction i.e. Reactants favored under standard conditions.
Gibbs free energy change sign criteria can easily tell us about the direction in which given reaction is favored.
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