Which is coldest?
☐ 0 degrees Centigrade (Celsius)
☑ 0 degrees Kelvin
☐ 0 degrees Fahrenheit
Suppose we have two jars of gas: one of helium and one of neon. If
both jars have the same volume, and the two gases are at the same pressure and
temperature, which jar contains the greatest number of gas molecules? (For this
question and the next, consider both gases to obey the ideal gas law.
Also note that the mass of a neon molecule is greater than the mass of a helium
☐ jar of helium
☐ jar of neon
☑ same number.
You mix some helium and neon gas together in the same container so they are
at the same temperature.
The average kinetic energy per helium molecule is
☐ greater than
☐ less than
☑ equal to
the average kinetic energy per neon molecule.
Ralph has a question about the reading assignment. The book says that if we heat
up a metal washer, all dimensions of the washer increase, including the diameter
of the hole. That is, the hole itself gets larger!
It seems to Ralph that the expansion of the metal would cause the outer
diameter to increase but the hole to decrease, because the metal
expands into the hole. Can you help Ralph understand how/why
the hole gets larger?
All dimensions increase, a bit like making a photographic enlargement.
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