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1. On a chilly 2°C day, your friend who likes cold weather says she wishes it we

ID: 1545600 • Letter: 1

Question

1. On a chilly 2°C day, your friend who likes cold weather says she wishes it were twice as cold. Taking this literally, what temperature would this be?
°C

2. Imagine a giant dry-cleaner's bag full of air at a temperature of -24°C floating like a balloon with a string hanging from it 11 km above the ground. Estimate its temperature if you were able to yank it suddenly to the Earth's surface.
°C

3. Helium has the special property that its internal energy is directly proportional to its absolute temperature. Consider a flask of helium with a temperature of 20°C. If it is heated until it has nine times the internal energy, what will its temperature be?
°C

Explanation / Answer

convert temperature from C to K

T = T _C + 273 = 2 + 273 = 275 K

Half of this is 137.5K.

T _C = T _K - 273 = 137.5 - 273 = -135.5 deg.C

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from the Ideal gas equation

P1 /T1 = P2/T2

here P2 =34.75 kPa

34.75kPa/249= 100 kPa/T1

T1 = 716.54 C

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total temperature in kelvein

273 + 20 = 293

total energy = 293 *9 = 2637 K

2637-273 = 2364 °C