Predict the sign of the entropy change for each of the following processes and g
ID: 911137 • Letter: P
Question
Predict the sign of the entropy change for each of the following processes and give your reasoning why:
1. Solid sugar is added to water to form a solution.
2. Iodine vapor condenses on a cold surface to form crystals.
3. N2(g) + 3H2 (g) 2 NH3(g)
4. H2O(l) H2O(g)
5. CaCO3(s) CaO(s) + CO2(g)
6. NH4NO3(s) + H2O(l) NH4+ (aq) + NO3- (aq)
7. freezing of water
8. boiling of water
9. crystallization of salt from a supersaturated solution
10. the reaction 2 NO(g) N2O2(g)
11. the reaction 2 H2(g) + O2(g) 2 H2O(g)
12. Fe(s) Fe(l)
13. 2 Fe(s) + 3/2 O2(g) Fe2O3(s)
14. HF(l) HF(g)
15. 2 H2O2(l) 2 H2O(l) + O2(g)
16. H2O(l) -> 2 H2(g) + O2(g)
17. CO(g) + 3 H2(g)-> CH4(g) + H2O(g)
18. 2 NaHCO3(s) ---> Na2CO3(s) + H2O(g) + CO2(g)
19. CO(g) + H2O(g) ----> CO2(g) + H2(g)
20. CaCO3(s) ----> CaO(s) + CO2(g)
21. 2NH3(g) + CO2(g) ----> NH2CONH2(aq) + H2O(l)
22. 2Na2O2(s) + 2H2O(l) ---> 4NaOH(aq) + O2(g)
23. C2H5OH(l) + 3O2(g) ---> 2CO2(g) + 3H2O(g)
Plz let me know how you did it.
Simple description is the best
Thanks
Explanation / Answer
1. Solid sugar is added to water to form a solution.--------------> positive
dissolution increases randomness
2. Iodine vapor condenses on a cold surface to form crystals.----------------> negative
vapour to liquid randomness decreases, so entropy decreases
3. N2(g) + 3H2 (g) -------------> 2 NH3(g) ----------------> negative
4 moles reactants , 2 moles products moles decreases, so entropy decreases
4. H2O(l) ----------------> H2O(g) -----------------> positive
liqiud to gas more random
5. CaCO3(s) --------------> CaO(s) + CO2(g) -----------------> positive
solid to gas more random more entropy
6. NH4NO3(s) + H2O(l) ---------------> NH4+ (aq) + NO3- (aq) -----------------> positive
7. freezing of water ----------------> negative
8. boiling of water -------------------> positive
9. crystallization of salt from a supersaturated solution --------------------> negative
10. the reaction 2 NO(g) N2O2(g) --------------------> negative
11. the reaction 2 H2(g) + O2(g) 2 H2O(g) --------------------> negative
12. Fe(s) Fe(l) --------------------> postive
13. 2 Fe(s) + 3/2 O2(g) Fe2O3(s) --------------------> negative
14. HF(l) HF(g) --------------------> positive
15. 2 H2O2(l) 2 H2O(l) + O2(g) --------------------> negative
16. H2O(l) -> 2 H2(g) + O2(g) --------------------> positive
17. CO(g) + 3 H2(g)-> CH4(g) + H2O(g) --------------------> negative
18. 2 NaHCO3(s) ---> Na2CO3(s) + H2O(g) + CO2(g) --------------------> positive
19. CO(g) + H2O(g) ----> CO2(g) + H2(g) --------------------> no change
20. CaCO3(s) ----> CaO(s) + CO2(g) --------------------> positive
21. 2NH3(g) + CO2(g) ----> NH2CONH2(aq) + H2O(l) --------------------> negative
22. 2Na2O2(s) + 2H2O(l) ---> 4NaOH(aq) + O2(g) --------------------> positve
23. C2H5OH(l) + 3O2(g) ---> 2CO2(g) + 3H2O(g)------------------> positive
note : common point in all
enrtopy increases in the following case
1) conversion of solid to liquid , liquid to gas
2) moles of product increases
3) phase change