– Unit 2 Energy Transfer Activity Honors Chemistry Background

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Honors Chemistry – Unit 2 Energy Transfer Activity
Background
From our discussion we came up with the following general principle:
When two objects are in contact, energy is continuously transferred in both
directions by random collisions between particles. The temperature of object A is
said to be lower than that of object B (TA < TB) if the rate of energy transfer from A
to B is lower than the rate in the reverse direction (B  A). This energy transfer
game will help visualize the exchange of energy quanta between two objects. The
game board is divided into arrays of circles that represent the particles in an object.
Rules of the Game
Round 1
1. The energy quanta should be evenly dispersed among the particles of the object.
Object A and object B have the same number of particles but object A has 20
quanta of energy and object B has 10 quanta of energy.
2. In a given turn, both players exchange simultaneously all the chips they have in
the interface column. Based on the number of chips exchanged, state the
relationship between TA and TB at the end of each turn.
3. At the end of each turn, both players are to redistribute all their chips evenly
over the columns in their side of the board. Decide a way to deal with the chips
that do not divide evenly among the columns. Will a different distribution give a
different result in the next turn?
4. Repeat steps 2 and 3 until you think it’s reasonable to stop playing. State your
reason for ending the game.
Round 2
The rules are the same as for Round 1 except that object B has twice as many
particles as object A and both objects contain the same amount of energy. [Note: It
is easier to exchange chips if the sheet of paper representing object B is folded over
and taped to the paper representing object A at the interface.]
Modeling Chemistry
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U2 E Transfer Activity v.pp
Round 1
turns
0
1
2
3
4
5
6
7
8
9
10
11
12
13
during a turn
A gives
B gives
at end of a turn
A has
B has
20
10
TA vs TB
Round 2
turns
0
1
2
3
4
5
6
7
8
9
10
11
12
13
during a turn
A gives
B gives
at end of a turn
A has
B has
15
15
TA vs TB
Modeling Chemistry
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U2 E Transfer Activity v.pp
Analysis
1. At the start of round 1, how did the rate of energy transfer from B  A compare to
the rate from A  B? Why do you think this was so?
2. At the end of round 1, how did the rate of energy transfer from B  A compare to
the rate from A  B? Why do you think this was so?
3. At the start of round 2, how did the rate of energy transfer from B  A compare to
the rate from A  B? Why do you think this was so?
4. At the end of round 2, how did the rate of energy transfer from B  A compare to
the rate from A  B? Why do you think this was so? How does your explanation
compare to that in Q2?
5. At the end of round 2, did A and B have the same amount of energy or the same
energy concentration? What’s the name we give to the energy concentration?
Modeling Chemistry
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U2 E Transfer Activity v.pp
6. In which direction does thermal energy flow?
7. When does the flow of thermal energy stop?
8. On the game board below represent a situation in which A is hotter than B.
A
B
9. On the game board below, represent a situation in which A and B are at the same
temperature.
A
B
Modeling Chemistry
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U2 E Transfer Activity v.pp