Question

2 PARTS

Which of the following transformations represent an increase in the entropy of the system.

Choose all that apply
35 g Pb (liquid, 601.0K)35 g Pb (solid, 601.0K)
19 g C2H5OH (liquid, 352K)19 g C2H5OH (gas, 352K)
4 mol He (7.89 L, 199K)4 mol He (15.8 L, 199K)
19 g C2H5OH (liquid, 164K)19 g C2H5OH (liquid, 347K)
4 mol N2 (1.75 atm, 495K)4 mol N2 (1.75 atm, 248K)

Predict whether S for each reaction would be greater than zero, less than zero, or too close to zero to decide.

Clear All
H2(g) + F2(g)2HF(g)
COCl2(g)CO(g) + Cl2(g)
2HBr(g) + Cl2(g)2HCl(g) + Br2(g)
4HCl(g) + O2(g)2H2O(g) + 2Cl2(g)
CaCO3(s)CaO(s) + CO2(g)

S > 0
S < 0
too close to decide

Answer 1

Ans :

Entropy refers to disorderness or randomness of the system. So when the entropy increases change in entropy is positive otherwise negative.

So here , the increase in entropy of the system is :

1)

19 g C2H5OH (liquid, 352K)19 g C2H5OH (gas, 352K)

4 mol He (7.89 L, 199K)4 mol He (15.8 L, 199K)

19 g C2H5OH (liquid, 164K)19 g C2H5OH (liquid, 347K)

2)

H2(g) + F2(g)2HF(g) : too close to decide

COCl2(g)CO(g) + Cl2(g) : S > 0

2HBr(g) + Cl2(g)2HCl(g) + Br2(g) : too close to decide

4HCl(g) + O2(g)2H2O(g) + 2Cl2(g) : S < 0

CaCO3(s)CaO(s) + CO2(g) : S > 0