1.0 kg of water is heated from $0 ^\circ \textrm{C}$ to $100 ^\circ \textrm{C}$. Estimate the change in entropy of the water.

VIDEO TRANSCRIPT

This is Giancoli answers with Mr. Dychko. The change in entropy of the water is going to be the amount of heat that it absorbs divided by the temperature and since the temperature is changing, we’ll approximate our change in entropy by using an average temperature. So the average temperature between zero and 100 is 50 and we'll change that into Kelvin by adding 273. So the average temperature is 323 Kelvin. And the amount of heat that it absorbs is mass times its specific heat times the change in temperature. So it's one kilogram times 4186 joules per kilogram Kelvin times by the change in temperature, 100 minus zero. And we get 418600 joules of heat absorbed. So take that energy absorbed by the water divided by the average temperature of 323 Kelvin and you get about 1.3 times ten to the three joules per Kelvin change in entropy. So, the entropy has increased.