# note that the latent heat of phase change and the change and the specific heat capacity must be considered. MASS OF ICE CUBES TEMPERATURE OF ICE CUBES a) 20g -6.0 deg c b) 10g -12 deg c c) 40g -3.0 deg c now answer these questions. (i) what is the effectiveness of cooling by sample (a)? (ii) what is the effectiveness of cooling by sample (b)? (iii) what is the effectiveness of cooling by sample (c)?

1
by ramya10class

2014-12-09T00:58:20+05:30

### This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Let us have a mass 100 gm of water at 40 deg C, in contact with the ice cubes in each case.

specific heat capacity of ice = 2.11 J/deg C/gm
Latent heat of fusion of ice = 334 J/gm
specific heat of water = 4.18 J/gm/degC

Heat energy that these ice cubes will take to reach 0 deg C and then melt at 0 deg C and then heat to T deg C is :

a) 20 gms at -6 deg C
20 * 2.11  * 6 + 20 * 334 + 20 * 4.18 * T =   6, 933.2 + 83.6 T   Joules
= 100 * 4.18 (40-T)
=>  T = 19.5 deg C

b) 10gm at -12 deg C
10 * 2.11 * 12 + 10 * 334 + 10 * 4.18 * T =  3,593.2  + 41.8 T  Joules
=  100 * 4.18 (40-T)
=>  T = 28.5 deg C

c )  40 gm at -3 deg C
40 * 2.11 * 3 + 40  * 334 + 40 * 4.18 * T =  13, 613.2  + 167.2 T Joules
= 100 * 4.18 (40-T)
=>  T = 5.3 deg C

Obviously the 40 gm ice cubes will be more effective.   Although the heat required to heat the Ice to zero deg C is same, the latent heat needed is highest for the 40 gm sample.