Question

Learning Task 3

Determine if liquid water will spontaneously freeze at -10.00 oC? Is it spontaneous at +10.00 oC? What can you say about

the values of ΔSuniv?

Answer 1

ΔS_univ = ΔS_sys + ΔS_surr

ΔS_sys is positive (22.1 J/K)

T1 = -10.00 C = 263.15 K

T2 = +10.00 C = 283.15 K

ΔS_surr = Q/T < 0!

If Q = 6.00 kJ, then at T1 ΔS_univ < 0 (melting is nonspontaneous, freezing is)

At T2 ΔS_univ > 0 (melting is spontaneous, freezing is not)