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