Physics ch. 21-23
Which would burn the most?
100 g of steam at 100 degrees C
The number of calories released when 3 grams of 100 degrees Celsius steam cools to become 3 grams of 0 degrees ice is
2160 calories
An air sample contains 25% of the amount of water vapor it is capable of holding. The air's relative humidity is
25%
One thousand calories of heat are added to 150 grams of water when it's temperature is 33 degrees C. The resulting temperature of the water is
40 degrees C
The energy needed to turn 43 grams of 100 degrees Celsius boiling water to 100 degrees Celsius steam is
43 X 540 calories
Mix a liter of 70 degrees C water with 2 liters of 40 degrees C water and you'll have 3 liters of water at
50 degrees C
How much energy is released when 1 gram of steam condenses to water at 100 degrees Celsius?
540 calories
A change in temperature of 10 degrees C is equal to
A change of 10 K
A good absorber of radiation is
A good emitter of radiation
A good reflector of radiation is
A poor absorber of radiatoon
Evaporation is a cooling process and condensation is
A warming process
Temperature is related mostly to the
Average molecular kinetic energy in a substance
If you take a shower in a steamy bathroom and then go to your bedroom to dry off, why will you feel colder in your bedroom?
Because water evaporates off of your skin, your skin will be cooled
The energy content of a piece of food is normally determined by
Burning the food
Which temperature scale labels the freezing point of water at 0 degrees?
Celsius
Ice is put in a cooler to cool the food stores there. In order to speed up the cooling process, you should
Crush the ice
A bimetallic strip will bend when heated because
Each metal expands at different rates
A piece of paper wrapped around a thick metal bar will not ignite when touched with a lit match because
Energy goes to the bar, preventing ignition temperature in the paper. The bar keeps the paper relatively cool. The bar is slow to heat up.
Heat is the
Energy transferred between objects because of a temperature differnece
When water at 4 degrees C is heated, it expands. When water at 4 degrees C is cooked, it
Expands
Energy transfer by convection is primarily restricted to
Fluids
Condensation occurs when matter changes from a
Gas to a liquid
When water freezes it
Gives off energy
Steam burns are more damaging than burns caused by boiling water because steam
Has more energy per kilogram than boiling water
The largest extremes in temperature are usually experienced
In the middle of the continent
Plastic foam is a good heat
Insulator
At high altitudes, the boiling point of water
Is lower
A liquid boils when
It turns to vapor at the bottom of or in the liquid
Heat is measured in
Kilocalories, joules, calories
If the specific heat capacity of water were higher tha it is, lakes would be
Less likely to freeze
Evaporation takes place when matter changes from a
Liquid to gas
The fact that desert sand is very hot in the day and very cold at night is evidence that sand has a
Low specific heat capacity
A piece of metal will feel colder than a piece of wood at the same temperature. Why?
Metals are good heat conductors
Specific heat capacity is related to the amount of internal energy
Needed to change the temperature of one gram of a substance one degree
Infrared radiation is a form of
Radiant energy
Heat travels from the sun to Earth by
Radiation
Planet earth loses heat primarily by
Radiation
The metallic coating on the glass surfaces of a Thermos vacuum bottle reduces the amount of energy transferred by
Radiation
The reason pressure cookers cook food faster is that they
Raise the cooking temperature of the food
The reason light colored clothes help keep you cool in warm weather is that clothes of light color
Reflect a lot of wnergy
When water vapor condenses on the inside of a window, the window becomes
Slightly warmwr
When heat is added to boiling water, the temperature of the boiling water
Stays the same
Two pots are filled with boiling water. The pots are exactly the same size, but one pot is white and the other is black. Which pot cools faster?
The black pot
To say that evaporation is a cooling process means that when evaporation occurs
The remaining liquid cools
On which day will the amount of water vapor in the air be greater, a summer day at 100% humidity or a winter day at 100% humidity?
The summer day
Newtons law of cooling says that the rate of cooling depends on
The temperature difference between an object and its surroundings
Internal energy is the
Total amount of energy contained in an object
The cooling effect inside a refrigerator is produced by
Vaporizing the refrigeration liquid
When snow forms in clouds, the surrounding air
Warms
Which has a higher specific heat capacity, water or sand?
Water
Which releases the most energy. 100 grams of 100 degrees C water cooling to 50 degrees C, or 100 grams of iron at 100 degrees C cooling to 50 degrees C?
Water
During a very cold winter, water pipes sometimes burst. The reason for this is
Water expands when freezing
The reason an ocean's temperature doesn't vary much from one season to the next is that
Water has a high specific heat capacity
Firewalkers who walk barefoot on red hot wooden coals depend on
Wood's poor conductivity
In a florist's greenhouse, glass acts as a one-way valve, letting
high frequency light in and preventing low frequency radiation from escaping
