Q&A Hero

Q: Distinguish between conduction and convection. Give examples of each.

Q: A piece of iron and a cup of water both at room temperature are heated such that the thermal energy of each doubles. Which has the higher temperature? A) the water, because of its higher specific heat capacity B) the iron, because it doesn't change phase C) both the same D) none of the above

Q: The number of grams of ice that can be melted by 1 g of 100C steam is A) 0.125 g. B) 0.148 g. C) 6.75 g. D) 8 g. E) none of the above

Q: Which requires more energy? A) melting a gram of 0C ice B) increasing the temperature of 1 gram of water from 0C to 100C C) changing 1 gram of 100C water to 100C steam D) all the same

Q: The heat of vaporization of ethyl alcohol Lv is about 200 cal/g. That means that 1 gram of this refrigerant upon vaporization would release A) less then 200 calories. B) 200 calories. C) more than 200 calories.

Q: To change 50 g of boiling water to steam requires A) 50 calories. B) 500 calories C) 540 calories. D) more calories than is required to bring 50 g of ice at absolute zero to the boiling point. E) none of the above

Q: To melt 50 g of 0C ice requires A) 25 calories. B) 50 calories. C) 80 calories. D) none of the above

Q: A heat pump can A) cool an environment. B) warm an environment. C) both of these D) none of the above

Q: Which will cool a drink faster? A) ice cubes B) crushed ice C) no difference for the same mass of ice

Q: You can add heat without raising temperature to A) ice. B) boiling water. C) both of these D) neither of these

Q: In walking barefoot on red-hot coals, to prevent bits of coal sticking to your feet, it would be safer if your feet are A) wet. B) dry. C) either of these D) none of the above

Q: In walking barefoot on red-hot coals, providing that bits of coal do not stick to your feet, it would be safer if your feet are A) wet. B) dry. C) either of these D) none of the above

Q: As a block of ice at 0C melts, the block absorbs energy A) and decreases in temperature. B) and increases in temperature. C) without a temperature change. D) all of the above E) none of the above

Q: Melting snow tends to A) warm the surrounding air. B) cool the surrounding air. C) neither of these

Q: When ice crystals form in clouds, the surrounding air A) warms. B) cools. C) neither of these

Q: When snow forms in clouds, the surrounding air is A) cooled. B) warmed. C) both of these D) none of the above

Q: When snow falls, the surrounding air is normally A) cooled. B) warmed. C) both of these D) none of the above

Q: We are warmed on a hot moist day because water molecules in the air striking our bodies A) transfer some of their kinetic energies to us. B) gain kinetic energy as they change state. C) form an insulating layer on our bodies.

Q: We feel uncomfortably warm on a muggy day because water molecules are A) evaporating from our moist bodies. B) condensing on our bodies. C) preventing the evaporation from our moist bodies.

Q: Boiling water burns are less damaging than steam burns because boiling water A) doesn't condense and release additional energy. B) has less energy per kilogram than steam. C) both of these D) none of the above

Q: Steam burns are much more damaging than boiling-water burns because steam A) has a higher temperature. B) releases more thermal energy. C) is hotter. D) is gaseous.

Q: Which would burn your skin the most? A) 100 g of water at 100C B) 100 g of steam at 100C C) both equal

Q: When steam condenses to water, energy is A) absorbed. B) released. C) conserved as the phase change occurs. D) transformed to a different form.

Q: When a solid is changed to a liquid phase, the solid A) releases energy. B) absorbs energy. C) neither of these D) none of the above

Q: When a gas changes phase to become a solid, energy is A) absorbed. B) released. C) unchanged.

Q: When a gas is changed to a liquid phase, the gas A) releases energy. B) absorbs energy. C) neither of these

Q: When salt is introduced to ice, the temperature at which melting occurs is A) quite unaffected. B) lowered. C) increased. D) dependent on the shape of salt and ice crystals

Q: When salt is introduced to water, the temperature at which freezing occurs is A) quite unaffected. B) lowered. C) increased. D) dependent on the shape of salt and ice crystals

Q: The addition of salt to water affects its A) crystal composition. B) freezing point. C) viscosity. D) liquidity. E) none of the above

Q: Foreign ions introduced to water A) lower the freezing point of water. B) raise the freezing point of water. C) do not affect water's freezing point.

Q: The temperature at which a liquid freezes is A) affected by foreign ions. B) the same temperature at which its solid form melts. C) both of these D) neither of these

Q: The temperature at which water freezes is the same as the temperature at which A) ice melts. B) water boils. C) both of these D) neither of these

Q: As ice is changed to water, energy is A) given to the ice. B) taken from the ice. C) neither of these

Q: As water changes to ice, water molecules A) absorb energy. B) release energy. C) retain their energy. D) lose the quality of wetness.

Q: If you keep decreasing the kinetic energy of atoms in a liquid, the liquid may A) melt. B) condense. C) solidify.

Q: If you keep increasing the kinetic energy of atoms in a solid A) melting may occur. B) freezing may occur. C) evaporation may occur.

Q: Melting and freezing are A) changes of phase. B) opposite processes. C) both of these D) neither of these

Q: When bringing water to a boil in the mountains, the time needed to reach the boiling point is A) less than at sea level. B) more than at sea level. C) the same as at sea level.

Q: When boiling your breakfast eggs while in the mountains, to compensate for altitude you should A) use a hotter flame. B) boil the eggs for a shorter time. C) boil the eggs for a longer time. D) none of the above

Q: Hydrothermal vents deep beneath the ocean surface attain temperatures far above 100C due to A) higher salt content. B) reduced salt content. C) greater pressure. D) all of the above E) none of the above

Q: In one word, account for water temperature exceeding 100C in the power plant of a nuclear submarine. A) conductivity B) evaporation C) condensation D) pressure E) vaporization

Q: Water boils in the mountains at A) a higher temperature than at sea level. B) a lower temperature than at sea level. C) the same temperature as at sea level.

Q: A good cook knows that the temperature of violently boiling water is A) higher than that of simmering water. B) the same as that of simmering water. C) actually lower than 100C. D) neither of the above

Q: Food in boiling water cooks slower in high-altitude locations. If you increase the stove temperature under the pot the food will cook A) faster. B) slower. C) neither of these

Q: Food is cooked faster in a pressure cooker due to its A) greater rate of bubble formation in the water. B) higher thermal energy. C) higher temperature. D) none of the above

Q: Increased air pressure on the surface of hot water tends to A) prevent boiling. B) promote boiling. C) neither of these

Q: Water can change phase to become ice by A) extraction of energy. B) lowering the surrounding air pressure. C) both of these D) neither of these

Q: Boiling and freezing can occur at the same time when water is subjected to A) decreased temperatures. B) decreased atmospheric pressure. C) increased temperatures. D) increased atmospheric pressure.

Q: Water can be brought to a boil by A) supplying thermal energy. B) reducing air pressure on its surface. C) both of these D) neither of these

Q: When water boils, energy added to the water is counteracted by A) decreased pressure in the water. B) static equilibrium. C) energy carried away by steam. D) energy of the whole system. E) none of the above

Q: When thermal energy is added to boiling water, the water temperature A) increases. B) decreases. C) remains the same.

Q: The process of boiling water tends to A) warm the water. B) cool the water. C) both of these D) none of the above

Q: Boiling is the process of evaporation A) beneath the water surface. B) at its extreme. C) that cools instead of warms.

Q: When a steaming-hot aluminum soda can is quickly inverted into a pan of water, the can is dramatically crushed due to a rapid decrease in internal pressure caused by A) contact with the cooler water. B) sudden slowing of internal air and steam molecules. C) condensation of steam inside. D) reduced thermal energy. E) rapid conduction of heat to the relatively cool water.

Q: A soda can with a small amount of water is on a hot stove. Soon steam comes from its opening. When the can is quickly inverted into a pan of water, the can is crushed by A) suction of the can interior. B) condensation. C) atmospheric pressure. D) a drop in temperature.

Q: If molecules in a sample of gas moved so they completely missed each other, with no other effects, the gas temperature would A) increase. B) decrease. C) remain unchanged.

Q: In a gaseous mixture of hydrogen and oxygen, the molecules having the greater average kinetic energy are A) hydrogen. B) oxygen. C) both the same D) not enough information

Q: In a gaseous mixture of hydrogen and oxygen, the molecules most contributing to temperature are A) hydrogen. B) oxygen. C) both the same D) not enough information

Q: In a gaseous mixture of hydrogen and oxygen, the faster molecules on average are A) hydrogen. B) oxygen. C) both the same D) not enough information

Q: In a gaseous mixture of hydrogen and oxygen, the slower molecules on average are A) hydrogen. B) oxygen. C) both the same D) not enough information

Q: Both heavy and light molecules make up a sample of gas. On average, the slower molecules are the A) heavy ones. B) light ones. C) no difference D) not enough information

Q: Which moves faster in a gas at the same temperature? A) light molecules B) heavy molecules C) Both have equal average speeds.

Q: A mixture of light and heavy molecules make up a sample of gas. If the temperature of the gas is constant, then all the molecules have the same average A) speed. B) kinetic energy. C) both of these D) none of the above

Q: Sublimation is a change of phase from solid to gas without A) passing through the liquid phase. B) a transfer of energy. C) a change of temperature.

Q: The toy dunking bird of Figure 7.28 operates by way of A) evaporation. B) condensation. C) both of these D) none of the above

Q: In a home steam radiator, thermal energy is released mainly by A) evaporation. B) condensation. C) sublimation. D) none of the above

Q: The dew that forms on a cold soda can when taken from a refrigerator is due to A) evaporation. B) condensation. C) sublimation. D) none of the above

Q: In a muggy region, the extra warmth you often feel is mainly due to A) evaporation. B) condensation. C) sublimation. D) none of the above

Q: After taking a shower and stepping outside the shower stall, the chill you often feel is mainly due to A) evaporation. B) condensation. C) sublimation. D) none of the above

Q: Pigs wallow in mud mainly to A) decrease thermal conductivity. B) shield themselves from the Sun. C) cool themselves by evaporation.

Q: A hot dog pants A) to help evaporation occur in its mouth and bronchial tract. B) to bring more oxygen into its lungs. C) for no particular reasonsome things just happen. D) to appear sexually appealing.

Q: What normally occurs in a saucer of water placed on your table is A) evaporation. B) condensation. C) both of these D) none of the above

Q: To say that evaporation is a cooling process is to say that the A) water left behind is cool. B) air cools as water warms. C) condensation is minimum.

Q: Evaporation is a cooling process because A) heat is radiated during the process. B) of conduction and convection. C) the more energetic molecules escape the liquid. D) none of the above

Q: When evaporation occurs in a dish of water, the molecules remaining in the water A) are less energetic. B) have decreased average speeds. C) are at a lower temperature. D) all of the above

Q: The molecules in a room-temperature glass of water jostle around at A) various speeds. B) much the same speed. C) constant speeds.

Q: Which is not a phase of matter? A) solids B) liquids C) gases D) vacuum

Q: To say you can never change only one thing means that when you change something, A) some other thing or things change. B) only one other thing will change. C) you can't reverse it.

Q: Long ago a runaway greenhouse effect greatly transformed the planet A) Mercury. B) Venus. C) Mars. D) none of the above

Q: Human activities that warm the Earth's atmosphere are caused by energy A) production. B) consumption. C) both of these D) none of the above