1) Boiling is sometimes called a ‘cooling process’. Why? A.) When you boil somet
ID: 1480071 • Letter: 1
Question
1) Boiling is sometimes called a ‘cooling process’. Why?
A.) When you boil something, the highest energy molecules escape through the surface tension of the liquid (i.e. evaporate), leaving behind molecules with lower energy and thus cooler temperature.
B.) The steam that condenses just above the boiling liquid’s surface cools as it rises.
C.) Energy is consumed in order to boil, therefore the surroundings lose energy and are cooled as a result.
D.) Boiling is certainly not a cooling process!
2) Modern homes use insulation made of spindled fiberglass to help a home retain heat in the winter. Why does this work so well?
A.) Fiberglass has a high thermal conductivity constant.
B.) The fiberglass has a low thermal conductivity constant and the spindled structure traps air (a good thermal insulator).
C.) The tiny surface area of the spindles slows heat conduction.
D.) The material is irrelevant; all that matters is that you make the wall effectively thicker to slow the heat transfer.
3) You observe a nearby lake to develop a sheet of ice at its surface on an extremely cold winter evening. What is the temperature of the liquid water at the bottom of the lake?
A.) 0 oC
B.) -273 oC
C.) 0 K
D.) -4 oC
4) You hold an ice cube initially ay 0 oC in your palm. Eventually some of the ice melts. Which is true regarding the remaining ice in your palm?
A.) It is at a temperature higher than 0 oC.
B.) It is at a temperature lower than 0 oC.
C.) It remains at 0 oC.
D.) Its temperature depends on how much ice is left over.
5) Which of the following is false regarding isochoric process of an ideal gas?
A.) The ratio of pressure to temperature is constant (i.e. P1/T1 = P2/T2).
B.) The ratio of volume to temperature is constant (i.e. V1/T1 = V2/T2).
C.) The work done on the gas is 0 J.
D.) There is no area under the curve in the P-V phase diagram.
Explanation / Answer
1) Boiling is cooling process as when you boil something, the highest energy molecules escape through the surface tension of the liquid (i.e. evaporate), leaving behind molecules with lower energy and thus cooler temperature i.e option is A
2) FiberGlass is used in modern homes because of how it is made, by effectively weaving fine strands of glass into an insulation material, Fiberglass is able to minimize heat transfer.
So best option in B
3) 4 degrees C turns out to be the temperature at which liquid water has the highest density. If you heat it or cool it, it will expand. The expansion of water when you cool it to lower temperatures is unusual, since most liquids contract when they're cooled.
So None of these options Options.
4) During Phase Changing, the Temperature remains constant.
Hence temperature remains same during melting so at 0o C
Option is C
5) Isochoric Process is the Process where volume remains constant. No change in volume can be seen
So P/T is constant as PV=nRT
Hence Option is A
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