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course PHY 232
Please submit a copy of the following questions and your answers, using the title ""Followup to Brief Bottle Experiment 1a"". The questions are brief and this should take you only a few minutes.
The main goal here is to associate what you have seen with the standard symbols for these quantities, and begin to think in terms of these symbols.
N stands for the number of air molecules in the bottle.
n stands for the number of moles of air in the bottle.
There are N_A = 6.02 * 10^23 particles in a mole, so N = n * N_A.
V stands for the volume of the gas.
T stands for its temperature.
P stands for the pressure within the bottle.
Answer the following:
If the sealed bottle is squeezed with the tube uncapped:
Which of the quantities P, V, N, n, T increase?
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None
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Which of the quantities P, V, N, n, T decrease?
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V, N, n
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Which of the quantities P, V, N, n, T remain unchanged?
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T, P
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List the quantities that change, and give a rough estimate of the percent change in each when you squeezed. A positive percent means the quantity increased, a negative percent means the quantity decreased.
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∆V= -5%
∆N= -1-2%
∆n=-1-2%
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@& N and n will change by the same proportion as V. The amount of gas decreases only because there is less volume for it to occupy.*@
If the sealed bottle is squeezed with the tube capped:
Which of the quantities P, V, N, n, T increase?
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P
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Which of the quantities P, V, N, n, T decrease?
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V
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Which of the quantities P, V, N, n, T remain unchanged?
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N, n, T
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List the quantities that change, and give a rough estimate of the percent change in each when you squeezed. A positive percent means the quantity increased, a negative percent means the quantity decreaseed.
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∆V= -5%
∆P= + 5%
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If the temperature of the gas remains constant, the average speed of the molecules bouncing around inside the bottle also remains constant.
If this is the case, and the volume decreases, do the individual molecules strike the walls of the container harder, do they strike more frequently, or both? Explain
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Both, since the physical space is smaller the distance travelled is smaller and the particles can strike more often. They must hit harder because P=(nRT)/V and if V gets smaller P becomes larger and P is determined by how hard the particles hit.
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Followup Part 1B
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Now please take a minute and answer the following. Submit a copy of just these questions, with your answers, using the title 'follow brief bottle experiment 1b'.
By how many degrees do you estimate you heated the bottle?
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∆T= +6
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By what percent did the length of the air column change as a result?
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-6%
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On a 1-10 scale, what squeeze would that correspond
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squeeze ≈ 4
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Followup Part 1D
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Based on your results for water column height vs. squeeze, and your previous results for percent change in air column length, report the expected percent change in air column length, and the expected height to which you would raise water (given a long enough tube), for squeezes of 1, 3, 6 and 9.
Just complete the lines below by adding the percent change, and the expected water column height, to each line:
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squeeze 1: 1%, +7 cm
squeeze 3: 5%, +20 cm
squeeze 6: 12%, 45 cm
squeeze 9: 20%, +62 cm
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self-critique #$&*
#$&* self-critique
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@& Looks good, but see my one note.*@