SCI Test 3

Harry places a new air conditioner in the middle of his hot room, which when operating.. cools the room, warms the room, or neither of these?

Air conditioners warm the room because the fan is doing work on the molecules and increases evaporation, which makes you feel cooler and warms the room.

As a system becomes more disordered, entropy.. increases, decreases, or remains the same?

As a system becomes more disordered, Entropy increases.

Absolute zero corresponds to a temperature of.. 0 K, -273°C, both of these, or none of these?

Both

If a 5°C piece of iron is heated until it has twice as much internal energy, what will its temperature be in degrees Celsius?

K=Tc+273; K=5°C+273= 278 K, (278)(2)= 556 K, 556-273= 283°C

All objects give off electromagnetic radiation. T/F

True, all objects give off electromagnetic radiation.

Evaporation could not take place if all the molecules in the water have the same speed. T/F

True, because none would be moving fast enough to jump off and evaporate.

When heated, a bimetallic strip will always bend towards the metal that expands the least.

True, the bimetallic strip always bends towards the metal that expands the least.

What is the efficiency of a thermal engine operating between a high temperature between 1000°C and 300°C?

e=(Th-Tc)/Th; Th=1000+273=1273 K, Tc=300+273=573 K. e=(1273-573)/1273=0.55 or 55%

Tomatoes have a higher specific heat capacity than dough. This means that when you bite into a hot pizza...

the tomato sauce feels hotter than the dough

What is the temperature that corresponds to absolute zero in °C?

-273°C

What is roughly room temperature?

20°C, 68°F, 293 K

What is normal body temperature?

37°C, 98.6°F, 310 K

At what temperature would 4 grams of water have its highest density?

4°C

At what temperature would 4 grams of water occupy the least volume?

4°C

What is the temperature at which water occupies the least space?

4°C; and is also most dense.

What is roughly the temperature of the surface of the sun?

5505°C, 9941°F, 5778 K

A block of wood and a block of copper will feel neither hot nor cold to the touch when they each have.. equal temperatures, your temperature, equal conduciveness, or none of these?

A block of wood and a block of copper will feel neither hot nor cold to the touch when they each have your temperature.

A heat engine would have 100% efficiency if its low-temperatures reservoir were.. as hot as its reservoir, at absolute zero, either of these, or neither of these?

A heat engine would have 100% efficiency if its low-temperatures reservoir were at absolute zero because e=(Th-Tc)/Th, so for it to equal 100% or (1/1), Tc would have to equal zero.

A volume of air that is compressed with no heat entering or leaving becomes.. cooler, remains unchanged, warmer, or none of the above?

A volume of air that is compressed with no heat entering or leaving becomes warmer because it is having work done on it.

The quantity of heat that a substance can transfer depends on its.. mass, specific heat capacity, change in its temperature, or all of the above?

All of the above (Q=mcΔT)

Which one is greater? An increase in temperature of 1°C, an increase in temperature of 1°F, or the same?

An increase in the temperature of 1°C is greater.

At absolute zero a substance has.. no energy or no translational kinetic energy?

At absolute zero a substance has no translational kinetic energy, or no more energy to give up; but only has minimal molecular motion.

Which unit represents the most energy.. calorie, Calorie, joule, or all the same?

Calorie represents the most energy.

The specific heat capacity of aluminum is more than twice that of copper. If equal amounts of heat are added to equal masses of aluminum and copper, which will undergo the greater increase in temperature?

Copper will undergo a greater change in temperature because it has a lower specific heat capacity.

Entropy is a measure of.. messiness, disorder, both, or neither?

Entropy is a measure of messiness and disorder.

The reason that evaporation is a cooling process is.. radiation of heat during the process, due to conduction and convection, the more energetic molecules escape the liquid, all of the above, or none of the above?

Evaporation is a cooling process because the more electromagnetic molecules escape the liquid.

To keep the energy consumption level low during the summer, one should replace dark colored window shades with a light colored one. T/F

False

At the same temperature a heavy and light molecule will have the same speed. T/F

False, at the same temperature the heavier molecule will have a lower speed and the lighter molecule will have a higher speed.

In general, electromagnetic radiation of longer wavelength is more dangerous than that of shorter wavelength. T/F

False, electromagnetic radiation of shorter wavelength is more dangerous than that of longer wavelength; ex. the Sun verses the Earth.

If you place a hot cup of coffee next to a giant iceberg, heat will spontaneously flow from the giant iceberg to the cup of coffee. T/F

False, heat flows from hot to cold no matter the size of the objects.

Heat and internal energy mean the same thing. T/F

False, heat is the flow of energy, whereas internal energy is the sum of all the potential energy and kinetic energy an object has; internal energy does not determine heat flow.

It is a violation of the first law of thermodynamics to state that "heat naturally flows from cold to hot." T/F

False, heat naturally flows from hot to cold; but not impossible to flow from cold to hot.

In a poor conductor of heat, the electrons in the outermost shell of an atom are loosely bound to the atom. T/F

False, in a poor conductor of heat the electrons in the outermost shell of an atom are tightly bound; but in a good conductor of heat the electrons are loosely bound.

A bimetallic strip will always bend towards the metal that has a higher thermal coefficient of expansion. T/F

False, the bimetallic strip bends towards the metal with the lower thermal coefficient of expansion, or the one that expands the least.

Both the Sun and the Earth give off electromagnetic radiation. The electromagnetic radiation from the Sun is of longer wavelength compared to that from the Earth. T/F

False, the electromagnetic radiation from the Sun is of shorter wavelength and higher frequency compared to that from the Earth.

The wavelength of the electromagnetic radiation from the Earth is shorter than that from the Sun. T/F

False, the electromagnetic radiation from the Sun is shorter because it is hotter than the Earth.

According to the second law of thermodynamics, the entropy of a system can never be decreased. T/F

False, the entropy can decrease in a system, but it is always increasing in the universe.

Because a cup of coffee is at a much higher temperature than the iceberg, it has more thermal energy than the iceberg. T/F

False, the iceberg has more thermal energy because of how massive it is; but the coffee cup has higher translational kinetic energy.

The smooth shiny surfaces of a thermos bottle eliminate heat loss by radiation. T/F

False, the smooth shiny surfaces of a thermos bottle reduces heat loss by radiation, but cannot fully eliminate it or prevent it.

In order to reduce heat loss from a house, the outside walls of a house should be built of materials that have a high thermal conductivity. T/F

False, the walls should have a low thermal conductivity to reduce heat from escaping.

Of the following electromagnetic waves, which one has the shorter wavelength? Infrared, Violet, Red, Blue, Gamma, Radio, or Visible

Gamma has the shortest wavelength.

If there were no greenhouse effect, Earth's average temperature would likely be.. near absolute zero, a frigid -18°C, comfortably cooler, or warmer than now?

If there were no greenhouse effect, Earth's average temperature would likely be a frigid -18°C.

If the specific heat capacity of water were lower than it is, a nice hot bath would be shorter, longer, or the same?

If water's specific heat were lower than a bath would be a shorter experience.

Increased air pressure on the surface of hot water tends to.. prevent boiling, promote boiling, both of these, or neither of these?

Increased air pressure on the surface of hot water tends to prevent boiling; whereas lower air pressure promotes boiling.

Of the following electromagnetic waves, which one has the lowest frequency.. Infrared, Violet, Red, or Blue?

Infrared has the lowest frequency.

At absolute zero, a substance has.. absolutely no molecular motion, no more energy to give up, no volume, or all of these?

It has no more energy to give up because it has no translational kinetic energy or energy to give up; but it has only the minimal amount of molecular motion.

A container holds helium gas that has a temperature of 20°C. If a second, identical container holding an equal mass of helium is twice as hot, what is its temperature in degrees Celsius?

K=Tc+273; 20°C+273= 293 K, (293)(2)= 586 K, 586 K-273= 313°C

Metals are good conductors of both heat and electricity due to.. similar thermal and electrical conductive properties, looseness of outer electrons in metal atoms, relatively high densities of metals, high elasticity of metals, or both transferring energy easily?

Metals are good conductors of both heat and electricity due to the looseness of outer electrons in metal atoms.

More efficient gasoline engines could be built if they could withstand.. greater rotational rates, lower temperatures, higher temperatures, or none of the above?

More efficient gasoline engines could be built if they could withstand higher temperature, remember e=(Th-Tc)/Th

The temperature of a certain gas is fixed at 80°F. Is it then correct to conclude that all the molecules in that gas have the same translational speed?

No, all the molecules in that gas do not have the same translational speed.

Open spaces in ice crystals contribute to.. decreased density, increased density, or neither?

Open spaces in ice crystals contribute to decreased density.

How much heat would it take to raise the temperature of 1 gram of water by 1°C?

Q=mcΔT; Q=(1)(1)(1)= 1 cal

How much heat would it take to raise the temperature of 3 grams of water from 10°C to 50°C?

Q=mcΔT; Q=(3)(1)(40)= 120 cal

What is the first law of thermodynamics in mathematical form?

Q=Δu+w

The change in internal energy induced by adding 100 joules to a system that does 60 joules of work is what?

Q=Δu+w; 100=Δu+60, Δu=40 joules

If you add 300 calories of heat to a system that does no work, what is the change in the internal energy of this system?

Q=Δu+w; 300=Δu+0, Δu=300 cal

Which color has the longer wavelength? Red, Blue, or the same

Red light has the longest wavelength.

Steam burns are more damaging than burns caused by boiling water because steam.. has more energy per gram than boiling water, it releases additional energy when it condenses, both of these, or neither of these?

Steam burns are more damaging than burns caused by boiling water because steam has more energy per gram than boiling water and it also releases additional energy when it condenses.

The addition of salt to water affects its.. crystal composition, freezing point, viscosity, liquidity, or none of these?

The addition of salt to water affects its freezing point; ex. putting salt on the ground to melt ice.

The amount of energy converted to light by an incandescent light bulb is about.. 10% and the amount converted to heat 90% or 90% and the amount converted to heat about 10%?

The amount of energy converted to light by an incandescent light bulb is about 10% and the amount converted to heat 90%, because light bulbs are much hotter compared to the amount of the light they give off and they have bad efficiency.

A balloon is filled with cold air and placed in a warm room. It is NOT in thermal equilibrium with the air of the room until the balloon.. rises to the ceiling, sinks to the floor, stops expanding, or starts to contract?

The balloon stops expanding; because the balloon is cold and is absorbing the warm air, it will expand till it has reached thermal equilibrium with the room and the air inside.

As the temperature of a certain mass of water is decreased from 4°C to 1°C, the density of that water decreases. What happens to the density of that same water as the temperature is increased from 4°C to 10°C?

The density decreases from 4°C to 10°C.

The first law of thermodynamics is a restatement of the conservation of.. momentum, energy, electric charge, all the above, or none of the above?

The first law of thermodynamics is a restatement of the conservation of energy.

The higher the temperature of an object the... longer the wavelength it radiates, shorter the wavelength it radiates, or makes no difference in the wavelength it radiates?

The higher the temperature, the shorter the wavelength it radiates.

Objects C and D are both as the same initial temperature and both have the same mass. If you add the same amount of heat to both, will they have the same final temperature? Yes, No, or it depends.

The objects may have the same final temperature but that depends on their specific heats (c).

The planet Earth loses heat primarily by.. conduction, convection, radiation, or all?

The planet Earth loses heat primarily by radiation.

The specific heat capacity is highest of substances that absorbs or release large quantities of heat for correspondingly.. small temperature changes, large temperature changes, both, or neither?

The specific heat capacity is highest of substances that absorbs or release large quantities of heat for correspondingly small temperature changes; ex. water can take large amounts of heat and barely change temperature.

Objects A and B are at the same temperature, 70°C, and have the same mass. Object A has a lower specific heat than B. If you want to raise the temperature of both to 80°C, which would require more heat.. A, B, or both the same?

To raise the temperature, Object B would require more heat because it has a higher specific heat and can take more heat without drastically increasing temperature.

Ultraviolet radiation is more energetic than Infrared radiation. T/F

True, because ultraviolet radiation has a higher frequency and a shorter wavelength, therefore more energy.

According to the second law of thermodynamics, it is impossible for heat to naturally flow from a cold environment to a hot one. T/F

True, heat cannot naturally flow from a cold environment to a hot one, but it can if it has a device (A/C) and energy (electricity).

The temperature of an object determines where that object is a net emitter or a net absorber of electromagnetic radiation. T/F

True, net emitters are cooler and net absorbers are warmer.

The energy associated with an electromagnetic wave depends on the frequency of the wave: the shorter the wavelength, the higher the energy. T/F

True, the energy associated with an electromagnetic wave depends on the frequency of the wave. Ex. the Sun has shorter wavelengths with higher energy, whereas the Earth has longer wavelengths with lower energy.

At pressures higher than atmospheric pressure, water will boil at temperatures higher than 100°C. T/F

True, the higher pressures require a higher temperature than 100°C; this means it's at a lower elevation.

If an object is a very good absorber of electromagnetic radiation, it must also be a good emitter of such radiation. T/F

True, the object must absorb and emit heat equally to maintain a temperature.

According to the second law of thermodynamics, no thermal engine can be 100% efficient. T/F

True, there can never be 100% efficiency because there will always be some waste; also the Tc will never be absolute zero to equal 100% efficiency.

Of the two types of radiation, which ones has the shorter wavelength.. Ultraviolet or Infrared?

Ultraviolet radiation will have the shorter wavelength and also higher frequency.

Of the following electromagnetic waves, which one has the shortest wavelength.. Infrared, Violet, Red, or Blue?

Violet has the shortest wavelength.

Water can be brought to a boil by.. applying heat, reducing air pressure on its surface, both of these, or neither of these?

Water can be brought to a boil by both applying heat and reducing air pressure on its surface.

When water evaporates off your face, your face feels cool. Is this an example that evaporation is a cooling process or an example that condensation is a warming process?

Water evaporating off your face and leaving your face cooler is an example that evaporation is a cooling process, because it bumps off the hotter/higher energy molecules and leaving the cooler ones.

Compared to sea level, water in an open pot in the mountains boils at.. a higher temperature, a lower temperature, the same temperature, or none of the above?

Water in an open pot in the mountains boils at a lower temperature compared to sea level because it has lower pressure.

When a solid is changed to a liquid, the solid.. releases energy, absorbs energy, both of these, or neither of these?

When a solid is changed to a liquid, the solid absorbs energy.

When a system does work without adding heat, the temperature of the system.. increases, decreases, remains unchanged, or none of the above?

When a system does work without adding heat, the temperature of the system decreases, because the system is doing the work. Also Q=Δu+w; 0=Δu+100J, then 0=-100J+100J, so decreasing.

When mechanical work is done on a system, in increase normally occurs in its.. internal energy, temperature, both, or neither?

When mechanical work is done on a system, in increase normally occurs in its internal energy and temperature because no energy is being released.

When most substances are heated, molecules inside move faster and take up more space, resulting in thermal.. bending, expansion, contraction, or heat?

When most substances are heated, molecules inside move faster and take up more space, resulting in thermal expansion.

When water at 4°C is heated it expands. If it is instead cooled it will.. contract, also expand, or neither?

When water at 4°C is heated it expands, and when it is cooled it will also expand.

When water vapor condenses, energy is.. absorbed by the vapor, released from the vapor, both of these, or neither of these?

When water vapor condenses, energy is released from the vapor into water.

Container 1 has Gas A in it. Container 2 has Gas B in it. The two containers (and gases) are at the same temperature. The molecules in Gas B are twice as massive as those in Gas A. Is it then correct to say that the two gases have the same average translational kinetic energy per molecule?

Yes, the two gases have the same average translational kinetic energy per molecule.

Gas A and Gas B are the same temperature. Is it then correct to say that the two gases have the same average translational kinetic energy per molecule?

Yes, they have the same temperature so the two gases have the same average translational kinetic energy per molecule.

What are the units of Latent Heat?

cal/g