Review Sheet for Energy Post-Test
Chemistry
2 points
DUE AT TEST (Thurs, 5/25/17)
Topics/concepts covered on post-test:
endothermic
exothermic
heat
temperature
energy conversion
direction of heat flow
specific heat calculations
Name: _______________________________
Date: _________________ Hour: _________
system
surroundings
specific heat capacity
energy units
energy diagrams (graphs) specific heat lab (#22)
Practice problems:
1)
What does exothermic mean? ________________________________________________
What does endothermic mean? _______________________________________________
2)
Look at the following energy diagrams. Which is exothermic? Which is endothermic? How
can you tell?
3)
Think about our specific heat lab with the unknown metal.
(a) What was the system? ______________________________________________________
(b) What were the surroundings (at least two)? _____________________________________
(c) Draw and label the lab set-up:
4)
Convert 5.62 Calories to joules.
[23 500 J]
5)
Convert 674 kJ to calories.
6)
(a) The definition of specific heat is ___________________________________________
[161 000 cal]
________________________________________________________________________
Material
Specific Heat
Capacity (J/gA°C)
Material
Specific Heat
Capacity (J/gA°C)
ethyl alcohol (CH3CH2OH)
2.4194
lead (Pb)
0.1276
concrete
0.84
rhodium (Rh)
0.2427
oxygen (O2)
0.919
water (H2O)
4.184
7)
8)
(b)
Which of the above materials has the highest specific heat capacity? ___________
(c)
Which of the above materials has the lowest specific heat capacity? ____________
(d)
Which of the above materials takes the most energy to heat up? _______________
(e)
Which of the above materials takes the least energy to heat up? ________________
Classify the following changes as exothermic or endothermic:
boiling
____________________
melting
____________________
freezing
____________________
sublimation
____________________
(a) What is the formula used with specific heat? What does each letter/symbol stand for?
(b) Use algebra to turn this formula into m =, c =, and ÄT =
9)
A piece of unknown metal with a mass of 149 grams is heated to 100.0 °C and then dropped
into 75.0 grams of water (with an initial temperature of 20.0 °C) in a calorimeter. The final
temperature of the system is 28.5 °C. What is the specific heat of the metal? [0.25 J/g·°C]