Physical Science Chapter 4
Suppose ammonia is spilled in the back of a room. If there were no air currents, how would the room temperature influence how fast you would smell ammonia at the opposite side of the room?
Warmer is faster.
Heat is the
total internal energy of an object.
Internal energy refers to the
total potential and kinetic energy of the molecules.
External energy refers to the
total potential energy and kinetic energy of an object that you can measure directly.
Radiation is the only method of heat transfer that can take place in a
vacuum.
The evaporation of water cools the surroundings and the condensation of this vapor
warms the surroundings.
Cooking pans made from which of the following metals would need less heat to achieve a certain cooking temperature?
Copper (specific heat 0.093 kcal/kgC)
Which of the following supports the second law of thermodynamics?
Energy tends to degrade, becoming of lower and lower quality.
Which of the following has the greatest value for liquid water?
Latent heat of vaporization.
The second law of thermodynamics tells us that the amount of disorder, called entropy, is always increasing. Does the growth of a plant or animal violate the second law?
No, the total entropy of the universe increased.
The transfer of heat that takes place because of density difference in fluids is
convection.
The transfer of heat that takes place by the movement of groups of molecules with higher kinetic energy is
convection.
A heat engine is designed to
convert heat into mechanical energy.
The cheese on a hot pizza takes a long time to cool because it
has a high specific heat.
Anytime temperature difference occurs, you can expect
heat movement from any higher-temperature region.
When you add heat to a substance, its temperature
might stay the same.
The Fahrenheit thermometer scale is
no more accurate than the Celsius scale.
The transfer of heat that takes place by energy moving through space is
radiation.
If you want to move heat from a region of cooler temperature to a region of warmer temperature, you must supply energy. This is described by the
second law of thermodynamics.
The temperature known as room temperature is nearest to
20°C.
Using the Kelvin temperature scale, the freezing point of water is correctly written as
273 K.
Conduction best takes place in a
solid.
Which of the following contains the most heat?
A barrel of water at 0 degrees C.
The specific heat of copper is roughly three times as great as the specific heat of gold. Which of the following is true for equal masses of copper and gold?
A piece of copper stores three times as much heat at the same temperature.
What form of heat transfer will warm your body without warming the air in a room?
Radiation.
The specific heat of copper is 0.093 cal/g°C and the specific heat of aluminum is 0.22 cal/g°C. The same amount of energy applied to equal masses, say 50.0 g of copper and aluminum, will result in
a higher temperature for copper.
As a solid undergoes a phase change to liquid, it
absorbs heat while remaining at a constant temperature.
At temperatures above freezing, the evaporation rate can equal the condensation rate only at
any temperature.
The temperature of a gas is proportional to the
average kinetic energy of the gas molecules.
More molecules are returning to the liquid state than are leaving the liquid state. This process is called
condensation.
The transfer of heat that takes place directly from molecule to molecule is
conduction.
The phase change from ice to liquid water takes place at
constant temperature.
The work that a heat engine is able to accomplish is ideally equivalent to the
difference between the heat supplied and the heat rejected.
The energy supplied to a system in the form of heat, minus the work done by the system, is equal to the change in internal energy. This statement describes the
first law of thermodynamics.
Convection best takes place in a (an)
fluid.
The heat death of the universe in the future is when the universe is supposed to
freeze at a uniform low temperature.
Latent heat is "hidden" because it
goes into or comes out of internal potential energy.
The specific heat of water is 1.00 cal/g°C and the specific heat of ice is 0.500 cal/g°C. The same amount of energy applied to equal masses, say 50.0 g of water and ice, will result in a greater temperature increase for the (assume the ice does not melt)
ice.
Styrofoam is a good insulating material because
it contains many tiny pockets of air.
The heat involved in the change of phase from solid ice to liquid water is called
latent heat of fusion.
The great cooling effect produced by water evaporating comes from its high
latent heat.
On the Celsius temperature scale
the numbers relate to the boiling and freezing of water.
The specific heat of soil is 0.20 kcal/kgC° and the specific heat of water is 1.00 kcal/kgC°. This means that if 1 kg of soil and 1 kg of water each receives 1 kcal of energy, ideally,
the soil will be 5°C warmer than the water.
