Chapter 5 - Matter and Heat
oxygen boils at -183 degrees Celsius. The Fahrenheit equivalent of this temperature is
-297 degrees F
a frictionless heat engine can be 100 percent efficient only if its exhaust temperature is
0 K
and ideal frictionless engine absorbs heat at 400 K and exhausts heat at 300 K. Its efficiency is
25 percent
the Celsius equivalent of a temperature of 120 degrees F is
49 degrees F
the physics of a refrigerator most closely resembles the physics of
a heat engine
at a given temperature, the molecules in a gas all have the same
average energy
molecular motion is not responsible for
buoyancy
one gram of steam at 100 degrees Celsius causes a more serious burn than 1g of water at 100 degrees Celsius because the steam
contains more energy
in any process, the maximum amount of heat that can be converted to mechanical energy
depends on the intake and exhaust temperatures
all molecules have the same size and mass: true or false
false
the working substance (or refrigerant) used in most refrigerators is a
gas that is easy to liquify
the temperature of a gas sample in a container of fixed volume is raised. The gas exerts a higher pressure on the walls of its container because its molecules
have higher average velocities and strike the walls more often
a person stands on a very sensitive scale and inhales deeply. the reading on the scale can
increase, not change, or decrease depending on the expansion of the persons chest compared with the volume of air inhaled
the maximum amount of mechanical energy that can be converted to heat
is 100 percent
when a vapor condenses into a liquid,
it gives off heat
at constant pressure, the volume of a gas sample is directly proportional to
its absolute temperature
on the molecular level, heat is
kinetic energy
the volume of a gas sample is increased while its temperature is held constant. the gas exerts a lower pressure on the walls of its container because its molecules strike the walls
less often
the density of fresh water is 1.00 g/cm cubed and that of seawater is 1.03 g/cm cubed. a ship will float
lower in freshwater than in seawater
absolute zero may be regarded as that temperature at which
molecular motion in a gas would be the minimum possible
a refrigerator gives off
more heat than it absorbs from its contents
buoyancy occurs because, as the depth in a fluid increases, the fluids
pressure increases
heat transfer in a vacuum can occur by
radiation only
heat transfer in a gas can occur by
radiation, convection, and conduction
an ice cube whose center consists of liquid water is floating in a glass of water. When the ice melts, the level of water in the glass
remains the same
a heat engine takes in heat at one temperature and turns
some of it into work and rejects the rest at a lower temperature
the pressure of the earths atmosphere at sea level is due to
the gravitational attraction of the earth for the atmosphere
food cooks more rapidly in a pressure cooker than in an ordinary pot with a loose lid because
the high pressure raises the boiling point of water
the greater the entropy of a system of particles,
the less the order of the system
when evaporation occurs, the liquid that remains is cooler because
the slowest molecules remain behind
the second law of thermodynamics does not lead to the conclusion that
the total amount of energy in the universe, including rest energy, is constant
the fluid at the bottom of a container is
under more pressure than the fluid at the top
heat is absorbed by the refrigerant in a refrigerator when it
vaporizes
when 1 kg of steam at 200 degrees Celsius loses 3 MJ of heat, the result is
water and ice
