Which of the following renu0:x bdt*e /sactions will have the greatest decrease in entropy?

  Which of the followingr dgd8hw(lh5x pk):3 c combinations of ΔH and ΔS results in the most spontaneous h (gx:w8d)lrc hp53kd reaction at 298 K?

  Which of the following statemat nl8zst 6e loj nfciv20+r+q745(e wents about entropy is incorrect?

  Which of the following compounds are arranged in order of dg(fjr9p9.h hwy v -3zwecreasing entropy?

$C$(s)
$H_2O$(l)
$O_2$
$CO_2$(g)
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  Which statement is true for an endothermic reaction that results in an u byi8mvo(*o4 increase in entropy?o8mv(y*u bo i4

  Which statement about the r(ly6ig** f vie*6u vrqelationship between Gibbs free energy change and the equilibrium constant is cor*(vviu *li6f6 yr*egqrect?

  Which of the following factors affectr ca1d5wzg fkhq- h y83t06x,r the entropy of a system containing gases? 0zyhf6 318rw-5xatkd ghr qc,
I. The temperature of the system
II. The states of the system
III. The pressure of the system

  The Gibbs free energy change can be used to determinr5b44l czsl5n yw hd)5e the spontaneity of a reactiwl sr5 )chldbz4554n yon.
1.1.Define Gibbs free energy change of formation.
1.2.Define spontaneous reaction.

2.1.State a correctly balanced equation that represents the complete combustion of butane.

2.2.Using section 12 (Section 13- 2025 Syllabus) of the data booklet, calculate the Gibbs free energy change of this reaction.
ΔG$_{reaction}$=-  kJ mol$^{-1}$
2.3.State, with a reason, whether this reaction is spontaneous or not.

Important note: The section numbers mentioned in the video solution are specific to the 2024 syllabus.
You can refer to the question stem to find the section numbers in the 2025 syllabus.

  Methanol is produced by reacting carbon monoxide and hydrogen accordim(m r r8 pyl92vf(vt:nng to the following reaction:fv8yr9v(n2rmm p :(t l
$CO(g)$+2$H_2(g)$ → $CH_3OH$(g)
$CO(g)$+2$H_2(g)$ ← $CH_3OH$(g)
1.Deduce the equilibrium constant expression for the formation of methanol.
At 500$^{\circ}C$ ,a 750cm$^3$ sealed flask is found to contain 0.923 mol of CH_3OH, 0.352mol of CO and 0.124 mol of $H_2$.
2.1.Calculate the value of K$_c$ at 500 $^{\circ}C$. K$_c$=  
2.2.Using sections 1 and 2 of the data booklet, calculate ΔG$^θ$ at 500 $^{\circ}C$.
T=  K;ΔG$^θ$=-  kJ mol$^{-1}$

  Ethanol can be produced th35mtk4cm xb2qkw/0nu rough the fermentation of glucose:
$C_6H_12O_6$(aq)→2$C_2H_5OH$(l)+2$CO_2$(g)
1.1.Predict whether the entropy change for this reaction is positive or negative. Explain your reasoning.
1.2.The absolute entropy for glucose is +209.2 J K$^{-1}$ mol$^{-1}$.Using section 12 (Section 13- 2025 Syllabus) of the data booklet, calculate the entropy change for this reaction.
ΔS$_{reaction}$=+  JK$^{-1}$ mol$^{-1}$

2.The enthalpy of formation of glucose is -1273.3kJ mol$^{-1}$.Using section 12 (Section 13- 2025 Syllabus) of the data booklet, calculate the enthalpy change for this reaction.
ΔH$_{reaction}$=-  kJ mol$^{-1}$

3.Using your answers to (a)(ii) and (b), calculate the Gibbs free energy change at 298K.
ΔG=-  kJ mol$^{-1}$
Important note: The section numbers mentioned in the video solution are specific to the 2024 syllabus.
You can refer to the question stem to find the section numbers in the 2025 syllabus.

  Dry ice, solid $CO_2$,is commonly used as a cooling or freezing agent in the medical and food industries.
1.Write an equation representing the sublimation of $CO_2$.
2.The enthalpy of sublimation for $CO_2$ is +26.1kJ mol$^{-1}$ and the absolute entropy of $CO_2$ in the solid state is 51.1 J K$^{-1}$ mol$^{-1}$.
2.1.Using section 12 (Section 13- 2025 Syllabus) of the data booklet, calculate the entropy change associated with the sublimation of $CO_2$.
ΔS$_{reaction}$=+  J K$^{-1}$ mol$^{-1}$
2.2.Using your answer to (bi), calculate the Gibbs free energy change for the sublimation of $CO_2$ at K.
ΔG=-  kJ mol$^{-1}$

3.Calculate the minimum temperature at which $CO_2$ sublimates.
T＞  K

Important note: The section numbers mentioned in the video solution are specific to the 2024 syllabus.
You can refer to the question stem to find the section numbers in the 2025 syllabus.

  How does Gibbs free energy relate to chemical equilibriu-o)zvb g f/9abm?

  Consider the followi.9 i 1nbgksaumew 8x24ng reaction:
$C_2H_4$(g)+$H_2$(g)→$C_2H_6$(g)
ΔH is -136kJ mol$^{-1}$
ΔS is -121jk$^{-1}$ mol$^{-1}$
ΔG at 298K is -99.9kJ mol$^{-1}$
1.1.Explain why the enthalpy of formation of $H_2$ is 0 kJ mol$^{-1}$.
1.2.Explain why the entropy change for this reaction is negative.

2.Explain how a reaction can be spontaneous with a negative entropy change.

3.Calculate the temperature at which this reaction is no longer spontaneous.
T=  K

  The following graph show ue-, f,rwfzi)s the Gibbs free energy against the extent of reaction for a reversible ,fi fu e),zwr-reaction.
At what point is the reaction at equilibrium?