Question

Above what temperature does the following reaction become nonspontaneous? FeO(s) + CO(g) → CO2(g) + Fe(s) ΔH = -11.0 kJ; ΔS = -17.4 J/K 191 K 298 K

Answer 1

Answer:

• 632 K

Explanation:

1) Reaction (given):

• FeO(s) + CO(g) → CO₂(g) + Fe(s)     ΔH = -11.0 kJ;

                                                                  ΔS = -17.4 J/K

2) Spontaneous reactions (ΔG < 0)

The sign of the change in free energy (ΔG) tells if a reaction is spontaneous or not at a given temperature and constant pressure.

If ΔG is negative ( ΔG < 0) the reaction is spontaneous; if ΔG is positive ( ΔG > 0) the reaction is nonspontaneous.

Then, determine the temperature at which ΔG becomes zero, which is the temperature at which the reaction becomes nonspontaneous.

3) ΔG⁰ = ΔH⁰ - TΔS⁰

ΔG⁰ = -11,000 J - T (-17.4 J/ K)  [ -11.0 kJ were converted to J]

0 = - 11,000 J + 17.4 T J/K

11,000 J = 17.4 T J/ k

T = 11,000 kJ / (17.4 J/K) =  632 K ← answer

Answer 2

The following reaction become nonspontaneous at 632.18 K

Further explanation

Gibbs free energy is the maximum possible work given by chemical reactions at constant pressure and temperature. Gibbs free energy can be used to determine the spontaneity of a reaction  

If the Gibbs free energy value is <0(negative) then the chemical reaction occurs spontaneously. If the change in free energy is zero, then the chemical reaction is at equilibrium ,if it is >0, the process is not spontaneous

Free energy of reaction (G) is the sum of its enthalpy (H) plus the product of the temperature and the entropy (S) of the system  

Can be formulated: (at any temperature)  

$\large{\boxed{\bold{\Delta G=\Delta H-T.\Delta S}}}$

or at (25 Celsius / 298 K, 1 atm= standart)  

ΔG°reaction = ΔG°f (products) - ΔG°f (reactants)  

Under standard conditions:  

∆G° = ∆H° - T∆S°

The value of ∆H° can be calculated from the change in enthalpy of standard formation:  

∆H° (reaction) = ∑H° (product) - ∑ H° (reagent)  

The value of ΔS° can be calculated from standard entropy data  

∆S° (reaction) = ∑S° (product) - ∑ S°(reagent)  

Reaction :

FeO(s) + CO(g) → CO2(g) + Fe(s)

ΔH = -11.0 kJ= -11000 J; ΔS = -17.4 J/K

ΔG =-11000 -(T.-17.4 J/K)

0 = -11000 + T17.4

T17.4 = 11000

T =632.18

Learn more  

Delta H solution  

brainly.com/question/10600048  

an exothermic reaction  

brainly.com/question/1831525  

as endothermic or exothermic  

brainly.com/question/11419458  

an exothermic dissolving process  

brainly.com/question/10541336  

Keywords: the standard gibbs free energy of formation,nonspontaneous