EASY
AS and A Level
IMPORTANT
Earn 100

The decomposition of calcium carbonate

CaCO3sCaOs+CO2g does not take place at room temperature.

Explain in terms of entropy changes why heating the calcium carbonate to a high temperature increases the likelihood of this reaction taking place.

Important Questions on Entropy and Gibbs Free Energy

EASY
AS and A Level
IMPORTANT

In a closed system at high temperatures, the reactants and products are in equilibrium.

CaCO3sCaOs+CO2g.

Explain the meaning of the term closed system.

 

EASY
AS and A Level
IMPORTANT

In a closed system at high temperature, the reactants and products are in equilibrium.

CaCO3sCaOs+CO2g.

Explain, in terms of entropy changes, what happens when the pressure on this system is increased.

 

EASY
AS and A Level
IMPORTANT

In a closed system at high temperatures, the reactants and products are in equilibrium.

CaCO3sCaOs+CO2g.

What is the value of the standard total entropy change at equilibrium?

 

EASY
AS and A Level
IMPORTANT

Calculate the standard Gibbs free energy of a given reaction, using the standard molar entropy values given. Express your answer to 3 significant figures in kJ mol-1, and in each case state whether or not the reaction is spontaneous under standard conditions.

Given:

H2g+Cl2g2HClg; Hreaction=-184.6 kJ mol-1Values for Sin J K-1 mol-1;HClg=186.8H2g=130.6Cl2g=165.

 

EASY
AS and A Level
IMPORTANT
Calculate the standard Gibbs free energy of a given reaction, using the standard molar entropy values given. Express your answer to 3 significant figures in kJ mol-1, and in each case state whether or not the reaction is spontaneous under standard conditions.

Given:

CH4g+2O2gCO2g+2H2O; Hreaction=-890.3 kJ mol-1Values for Sin J K-1 mol-1;H2Ol=69.9CO2g=213.6O2g=205.0CH4g=186.2.

EASY
AS and A Level
IMPORTANT

Calculate the standard Gibbs free energy of a given reaction, using the standard molar entropy values given. Express your answer to 3 significant figures in kJ mol-1, and in each case state whether or not the reaction is spontaneous under standard conditions.

Given:

2Nas+O2gNa2O2s; Hreaction=-510.9 kJ mol-1Values for Sin J K-1 mol-1;Na2O2s=95.0Nas=51.2O2g=205.0.

 

EASY
AS and A Level
IMPORTANT

Calculate the standard Gibbs free energy of a given reaction, using the standard molar entropy values given. Express your answer to 3 significant figures in kJ mol-1, and in each case state whether or not the reaction is spontaneous under standard conditions.

Mgs+Cl2gMgCl2s; Hreaction=-641.3 kJ mol-1Values for Sin J K-1 mol-1;MgCl2s=89.6Mgs=37.2Cl2g=165.

 

EASY
AS and A Level
IMPORTANT

Calculate the standard Gibbs free energy of a given reaction, using the standard molar entropy values given. Express your answer to three significant figures kJ mol-1, and in each case state whether or not the reaction is spontaneous under standard conditions.

Ag2CO3sAg2Os+CO2; Hreaction=+167.5 kJ mol-1Values for Sin J K-1 mol-1;Ag2Os=121.3CO2=213.6Ag2CO3s=167.4.