1 at what temperature will the following reaction become...

At what temperature will the following reaction become spontaneous under standard conditions? CaCO3 (s) → CaO (s) + CO2 (g) ΔH° = 174.2 kJ, ΔS° = 160.2 J/K A) −271.9°C B) 629.7°C C) 814.4°C D) 1087.4°C E) none of these 2. Calculate the entropy change (ΔS) for the following phase change at its normal boiling point. H2O (l) → H2O (g) ΔH = 40.7 kJ A) −9.2 J/K B) +9.2 J/K C) −109 J/K D) +109 J/K E) none of these 3. Which of the following statements is true? A) The standard enthalpy of formation, ΔHf°, of N2(l) is zero. B) In an endothermic reaction, heat is transferred from the system to the surroundings. C) The 2nd Law of Thermodynamics indicates that the entropy of the universe is always increasing. D) CO(g) has a larger standard entropy (S°) than CO2(g). E) All of the above are true

Transcript

00:01 Students let me explain you the question here at what temperature will the following reaction become spontaneous under standard conditions so we have to find out the temperature so so that the reaction becomes spontaneous the reaction becomes spontaneous under standard conditions under standard conditions so the reaction given here it is c c o 3 solid that gives rise to c a solid solid plus co2 gas okay so delta h of the reaction that is enthalpy change of reaction is 174 .2 kilojoules and the entropy change of the reaction that is 160 .2 jolts per kelvin so these are the values given here we have to find out at what temperature the reaction become spontaneous the temperature we have to find out coming to the solution here so what we know that the relation between delta g, delta h, delta h and t, that is delta g is equal to, that is, gyps free energy, it is equal to delta h minus d delta s.

01:15 So it is the enthalpy change, enthalpy change and entropy change.

01:23 So entropy change.

01:29 So here this is the gyps free energy.

01:33 Gyps free energy change okay free energy change so here as per the question now we see delta h is equal to 174 .2 kilojoules that is positive the value here it is positive delta s is equal to 160 .2 jolts per kelvin that is the entropy change also positive so the delta g value should be negative so delta g in this case delta g it is negative and t that is temperature it is positive so higher the positive charge that means here so higher the positive value of t higher will be the higher will be the negative value for delta g so the reaction will be spontaneous then the reaction will be spontaneous so among the four options here 187 .4 degrees it is the highest value in temperature among the values highest value in temperature is 187 .4 degrees centigrade so at this particular temperature the reaction becomes spontaneous at this particular temperature reaction becomes spontaneous so that answer is 187 .4 degree centigrade then coming to the next question here so in the next question we have to calculate the entropy change entropy change so entropy change delta s so for the following phase change is normal boiling point at its normal boiling point okay is equal to water liquid it gives rise to water gas that is liquid water it is converted into vapor the enthalpy change here it is 40 .7 kilojoules we have to find out the entropy change so entropy change that is chemical equation here it is h2o liquid is equal to water vapor so here the process it is nothing but the vaporization so vaporization so the particular vaporization process it takes place at boiling point.

04:12 So vaporization, when the liquid it is converted into gas, so at its boiling point, the boiling point of water, it is 100 degrees centigrade, that is equal to 373 kelvin's.

04:25 So the temperature here it is 373, temperature 373 kelvin's.

04:31 So delta h of the vapor, that is equal to 40 .7 kilojoules, that is equal to 40 .7 .7...

Question

Please give Ace some feedback