This assignment covers how much heat it takes to change water from solid ice to liquid, and to change liquid water into water vapor or steam.
Read pages 339-345. Then on pages 347-350 do these problems:
Review # 2, 4, 5, and 8 Plug and Chug # 1, 2, 3, and 4. Please be careful with your math on the Plug and Chug problems.
Remember, there are TWO formulas:
Q = m c delta T use when things are changing temperature
Q = m X energy required for the phase change
For instance, if you want to melt 10 grams of ice at 0 degrees C and turn it into 10 grams of liquid water at 0 degrees C, then you have to add heat energy. It takes 80 calories to change ONE gram of solid water to melt into liquid.
So, to melt 10 grams, you would have to add 10 grams X 80 calories / gram = 800 calories.
For vaporizing water, it require MORE energy. To turn 1 gram of water at 100 degrees C into 1 gram of steam at 100 degrees C, it take 540 calories! SO..
To change 25 grams of water at 100 degrees C into 25 grams of steam at 100 degrees:
25 grams X 540 calories / gram = 13,500 calories or 13.5 kilocalories
Read pages 339-345. Then on pages 347-350 do these problems:
Review # 2, 4, 5, and 8 Plug and Chug # 1, 2, 3, and 4. Please be careful with your math on the Plug and Chug problems.
Remember, there are TWO formulas:
Q = m c delta T use when things are changing temperature
Q = m X energy required for the phase change
For instance, if you want to melt 10 grams of ice at 0 degrees C and turn it into 10 grams of liquid water at 0 degrees C, then you have to add heat energy. It takes 80 calories to change ONE gram of solid water to melt into liquid.
So, to melt 10 grams, you would have to add 10 grams X 80 calories / gram = 800 calories.
For vaporizing water, it require MORE energy. To turn 1 gram of water at 100 degrees C into 1 gram of steam at 100 degrees C, it take 540 calories! SO..
To change 25 grams of water at 100 degrees C into 25 grams of steam at 100 degrees:
25 grams X 540 calories / gram = 13,500 calories or 13.5 kilocalories