CHAPTER 12 REVIEW:
LAW OF HEAT EXCHANGE
#1 How much heat must be taken away from steam at 200 degrees Celcius to change it into water at 100 degrees Celcius ?
#2 How much heat must be added to solid aluminum at its melting point tochange it into liquid aluminum ?
#3 How much heat is absorbed by ice at –20 degrees Celcius to change it into steam at 150 degrees Celcius ?
#4 An element has the following knowns:
mass: 800 grams
current temp.: 25 degrees Celcius
specific heat: solid form 1200 J/kg K
liquid form 1500 J/kg K
gas form 1000 J/kg K
melting point: 50 degrees Celcius
boiling point: 130 degrees Celcius
Find the heat needed to change the substance into a gas at 130 degrees Celcius.
#5 If 250 grams of aluminum at 200 degrees Celcius is mixed with 200 grams of water at 30 degrees Celcius, what will the final temperature of the mixture be ?
#6 If the heat needed to change 1 kilgram of water at 0 degrees Celcius to water at 100 degrees Celcius were used to boil water at its boiling point, how much water could be boiled ?
#7 A 40 gram calorimeter contains 500 grams of liquid methanol at 40 degrees celcius. If a piece of brass with a mass of 300 grams at a temperature of 300 degrees Celcius is dropped in, what will the final temperature of the mixture be ?
#8 A piece of metal with a mass of 5 kilograms and a temperature of 250 degrees Celcius is dropped on a huge block of ice at 0 degrees Celcius. If the metal cools to 0 degrees before all of the ice is melted, how much of the ice will have melted ?
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