Question

22. For the following redox reaction Mgso4 (aq)+ Ba(s)-BaSOa(s)+ Mg (aq) Indicate the species being oxidized, the species being reduced, the oxidizing agent, and the reducing agent. 23. Which of the following involve an increase in the entropy of the system? (circle all that applies) a) melting of a solid b) sublimation c) freezing d) mixing e) boiling 24. Calculate ASurr for the following reactions at 25°C and 1 atm: CsHa(g) + 502(g) → 3CO2(g) + 4H20(I) 솨1°--222lki

Answer 1

Q22

Reduction = species that GAINS electrons

Oxidation = process in which a specie will LOSS electrons

Reducing agent = The species that favors reduction, i.e. it will oxidize in order to reduce another species

Oxidizing agent = The species that favors oxidation, i.e. it will reduce in order to oxidise another species

then

Mg goes from +2 in MgSO4 to 0 in Mg, it gains 2e- then reduces. Therefore,MgSO4(aq) is the ox. agent

Ba goes from 0 to +2, then it is oxidized; therefore, Ba(s) is red. agent

Q23

entropy --> order of a system

a)

metling a solid will increase chaos, since liquid moves faster, then increases

b)

sublimation is solid to gas, therefore, icnreases chaos drastically, i.e. entropy is positive

c)

freezing is reverse as in a, therefore, negative change

d)

mixing -> two ordered states, A, B will form 1 chaotic mix, A+B, increases

e)

boils is simlar to sublimation, liquid goes to chaotic gas, increases

q24

Ssurr = QSurr/T

Qsurr= - Qsystme = -Hsystem

then

Ssurr = -Hsystem/T = -(-2221*1000)/(298)= 7453.02 J/K