Answer to Question #175525 in General Chemistry for Ava Brooke

Question

Reading (30s) Temp (oC)

1 99.2

2 72.8

3 70.5

4 66.9

5 63.9

6 61.4

7 58.2

8 56.1

9 53.8

10 51.9

11 50.1

12 48.4

13 47.5

14 46.6

15 45.9

16 45.3

17 44.9

18 44.5

19 44.1

20 43.9

21 43.8

22 43.6

23 43.5

24 43.4

25 43.4

26 43.3

27 43.3

28 43.3

29 43.3

30 43.3

31 43.3

32 43.3

33 43.3

34 43.3

35 43.3

36 43.3

37 43.3

38 43.1

39 43

40 42.9

What was the freezing point of the lauric acid from the data?

Answer 1

From the data, the freezing point of Lauric acid is 43.3^oC

Freezing point is the temperature at which a liquid changes its phase to become a solid. Freezing point of a pure substance is a constant temperature. This is because the process involves cooling liquid particles to rejoin the very strong bonds holding the particles very close to each other as solid, and thus the particles lose their degree of freedom (Kinetic Theory of matter).

This process is exothermic (-$\Delta$H) and requires the particles to lose energy to the surrounding. That is why during freezing the temperature of the system remains constant as heat loss from the system is being replenished by the heat supplied by the forming bonds.

Theoretically, Lauric acid freezes at 43.2^oC, hence the data is consistent with the theoretical value