Question

Part A Predict the sign of the entropy change, AS°,for each of the reaction displayed. Drag the appropriate items to their respective bins. Ag+(aq) + Cl-(aq) → AgCl(s) | | Ca(OH)2(s) → CaO(s) + H2O(g) 2N20(g)--2N2(g) + O2(g) | | 2Na(s) + Cl2(g) → 2NaCl(s) C,Hs(g) + 602(g) → 4CO2(g) + 4H20(g) | | CH3OH(l) → CH3OH(g) Positive Negative resethelp ? help

B. Calculate the standard entropy change for the reaction

2Na(s)+Cl2(g)?2NaCl(s)

using the data from the following table:

Substance	?H?f (kJ/mol)	?G?f (kJ/mol)	S? [J/(K?mol)]
Na(s)	0.00	0.00	51.30
Cl2(g)	0.00	0.00	223.1
NaCl(s)	-411.0	-384.0	72.10

Express your answer to four significant figures and include the appropriate units.

Answer 1

PART A Ag+ (aq) + Cl-(aq)→ AgCl (s) The number of moles of reaction decreases from reactants to products Two aqueous solutions forming one solid compound. So the disorderness decreases. Hence, AS° decreases Ca (OH)2 (s) CaO (s)+H20g) The number of moles of reaction increases from reactants to products One compound decomposes into two compounds. So the disordemess increases. Hence, ASincreases. The number of moles of reaction increases from reactants to products Two moles compound decomposes into three moles. So the disorderness increases. Hence, AS increases. 2Na (s) + Cl2 (g) → 2NaCl (s) Theere is an gas moleule present in the reactant side. So the disorderness increases in reactants. Hence, AS° decreases CH, (g) +60 2 (g) → 4C0 2 (g)+ 4H20(g) The number of moles of reaction increases from reactants to products So the disorderness increases. Hence, AS increases CH,OH (1) → CH, OH (g) The liquid is converting into gas.So the disordemess increases Hence, ΔSo Increases Therefore Positive Negative Ag+ (aq) + Cl-(aq) → AgCl (s) 2Na (s)-C12 (g) → 2NaCl(s) Ca(OH) (sCaO(s) +H,O (g 2N20(g) → 2N2 (g)+0 2 (g) CHOH ()- CH OH(g)

PARTB The given equation is, 2Na (s) + Cl2 (g) → 2NaCl (s) reaction productsreactants = [2s0 (NaCl(s))]-[2s* (NaCl (s))+So (Ci, (g))] -[2072.10)][2(51.30)+223.1] J/mol K 一一181.5 J/mol . K 2.S Hence, the ASpact of the reaction is -181.5 J/mol K