Question: Heat Calculations The Transformation Of Water Across Phase Boundaries Involves A Lot Of Heat. The Oceans Are Big And Ocean Water Constantly Changes Phase Boundaries. For Example, Every Year The Sun Evaporates 434,000 Km3 Of Seawater Into The Atmosphere! That Represents An Incredible Amount Of Heat. We Will Start With Smaller Values. Example Problem: …

Heat calculations The transformation of water across phase boundaries involves a lot of heat. The oceans are big and ocean water constantly changes phase boundaries. For example, every year the sun evaporates 434,000 km3 of seawater into the atmosphere! That represents an incredible amount of heat. We will start with smaller values. Example problem: How much heat does it take to raise the temperature of 1 liter (=1000 grams) of water from 50° C up to 100° C and then evaporate it? That is a change of 50° C, so the first equation describes the heat needed to get it to 100° C. It is the specific heat of water by the amount of water by the change in temperature. Notice how most of the units cancel. (1 calories/gram/1° C) x (1000 grams) x (50° C) = 50,000 calories This equation describes the heat needed to evaporate the liter of water once it reaches 100° C. (540 calories/gram) x (1000 grams) = 540,000 calories The total (both answers added)=590,000 calories 2)The oceans evaporate 434,000 km3 of water each year, due to the radiation from the sun That’s a vast amount of water. Converted to grams it is 1 x 1015 grams. c) If a big piece of pizza has 1000 Calories, how many pieces of pizza would you need to burn up in order to evaporate all the seawater that the sun does in one year? Again divide by 1000 (or remove three zeroes, same thing).