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Heat
Heat Transfer
Vocabulary
Specific Heat
Other
100
The standard unit for measuring heat
What is a joule (J)
100
1. Which equation would you use during a phase change? 2. Which would you use during a single phase? A. q=mCΔT B. q=nΔHx
1. B 2. A
100
The capacity to do work or to supply heat
What is energy
100
What units are specific heat measured in?
What is J/g°C or cal/g°C
100
Give two examples of endothermic processes
An ice pack, melting ice, boiling water, getting warm by a fire, etc
200
Another unit for measuring heat (not SI)
What is a calorie
200
How much energy would it take to increase the heat of 72.0 g of liquid water by 20.0°C? (the specific heat of liquid water is 4.18 J/g°C)
What is 6019.2 J (for significant figures: 6.02x10^3 J)
200
The quantity of heat that raises the temperature of 1 g of pure water by 1 degree C
What is a calorie
200
Does the value of specific heat EVER change? If so, when?
No, it is a constant
200
Give two examples of an exothermic process
A candle flame, a hot pack, freezing water, condensing steam, combustion, etc
300

What does each symbol in the equation q = mCΔT represent?

q = heat m = mass (in grams) C = specific heat ΔT = change in temperature (in Celsius)

300
What would be the temperature change of 125.0g of steam be if you added 400.0J of heat to it? (the specific heat of steam is 1.9 J/g°C)
What is 1.68°C
300
A process in which heat is released
What is an exothermic process
300
Is the specific heat for metal generally higher or lower than for water? Why?
The specific heat for metal is lower than that of water. This is because it takes quicker for metal to heat up and cool down.
300
How do you convert J to kJ?
What is you divide by 1000
400

In which direction does the heat flow? (Coffee to ice, or ice to coffee?)


Heat always flows from hot to cold (Coffee ->Ice).


400
How much heat is released by 9.0 moles of liquid water that is freezing? (the heat of fusion is 6.01 kJ/mol)
What is -54.09kJ (with significant figures -54kJ)
400
A process in which heat is absorbed
What is an endothermic process
400
What is the specific heat of a metal which has a mass of 25.0g, a temperature change of 50.0 degrees Celsius, and absorbed 162.4J of heat?
What is 0.130 J/g°C
400
If you are looking at an ice cube melting on the counter, what is the system? What are the surroundings?
The system is the ice cube. The surroundings are everything else (the counter, the air, the people around the ice cube, etc)
500

Two different substances, Substance A (0.24 J/gC) and Substance B (4.18 J/gC), have the same mass and start at the same temperature. If you add 100 J of heat to both. Which substance will show a larger increase in temperature?


 

A will show the larger increase. Specific heat is "resistance" to temperature change; the lower the number, the faster it heats up.

500
How many grams of ice would melt if you added 75.0kJ of heat? (the heat of fusion is 6.01 kJ/mol)
What is 225 grams (12.48 moles)
500
A device used to measure the amount of heat absorbed or released during a process which separates one surrounding from all of the surroundings
What is a calorimeter
500
How much heat is required to raise the temperature of 250.0g of mercury by 52.0°C? (the specific heat for mercury is 0.14 J/g°C)
What is 1820J
500
Calculate the heat it takes to melt 10.0g of ice at 0.00°C to 50.0°C. The specific heat of liquid water is 4.18 J/g°C, the specific heat of ice is 2.1 J/g°C, and the heat of fusion is 6.01 kJ/mol (in kJ).
What is 5.43kJ