PS 205 Test 2

A firewalker walking barefoot across hot wooden coals depends on wood's A. Good conduction B. Poor conduction C. Low specific heat capacity D. Wetness

B

Before ice can form on a lake, all the water in the lake must be cooled to A. 0°C B. 4°C C. A value slightly below 0°C

B

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

B

An integer that specifies the quantized energy level of an atomic orbital

Principle quantum number n

A positively charge subatomic particle of the atomic nucleus

Proton

The pattern of frequencies of electromagnetic radiation emitted by the atoms of an element, considered to be an element's "fingerprints"

Atomic spectrum

An abbreviation for an element or atom

Atomic symbol

Uranium 238 has 238 nucleons. The atomic number of uranium is 92, how many neutrons are in uranium? Mass number-atomic number=neutrons

146 neutrons

1 calorie = how many joules

4.19 J

A friend says that a can of beverage will cool faster in the coldest part of a refrigerator. Knowledge of Newton's law of cooling A. Supports this statement B. None of the above C. Shows this statement is false

A

A poor conductor of heat is a A. Good insulator B. Poor insulator C. Neither

A

An element found in another galaxy exists as two isotopes. If 80.0% of the atoms have an atomic mass of 80.00 atomic mass units, and the other 20.0% have an atomic mass of 82.0 atomic mass units, what is the approximate "atomic mass" of the element? A. 80.4 amu B. 81.0 amu C. 81.6 amu D. 64.0 amu E. 16.4 amu

A

Glass is transparent to short-wavelength light and is A. Opaque to light of longer wavelengths B. Opaque to the same light that is reflected from an interior surface C. Both of these D. None of these

A

If a neutral element has the following chemical notation, how many electrons does it have? fluorine-19 A. 9 B. 11 C. 10 D. 19

A

In a gaseous mixture of hydrogen and oxygen, the molecules having the greatest average kinetic energy are A. Both the same B. Oxygen C. Not enough information D. Hydrogen

A

Increasing the temperature of 50 grams of water by 1°C requires A. 50 calories B. None of the above C. No answer text provided D. 1 calorie

A

Suppose you rapidly stir some raw eggs with an egg beater. The temperature of the eggs will A. Increase B. No answer text provided C. Remain unchanged D. Decrease

A

The gush of steam that issues from the escape valve of a pressure cooker is relatively cool A. Above the opening where expansion is prominent B. None of the above C. Close to the opening

A

The isotope lithium-7 has a mass of 7.0160 atomic mass units, and the isotope lithium-6 has a mass of 6.0151 atomic mass units. Given the information that 92.58 percent of all lithium atoms found in nature are lithium-7 and 7.42 percent are lithium-6, calculate the atomic mass of lithium, Li (atomic number 3). A. 6.942 amu B. 6.495 amu C. 7.0160 amu D. 13.031 amu

A

The motion of molecules that most affects temperature is A. Translational motion B. Rotational motion C. Internal vibrational motion D. Simple harmonic motion

A

When air is rapidly compressed, its temperature normally A. Increases B. Decreases C. Remains unchanged D. Is unaffected, but not always

A

When you touch a piece of ice with your finger, energy flows A. From your finger to the ice B. Both ways C. From the ice to your finger

A

You could swallow a capsule of germanium, Ge (atomic number 32), without significant ill effects. If a proton were added to each germanium nucleus, however, you would not want to swallow the capsule, because the germanium would A. Become arsenic B. Become radioactive C. Expand and probably lodge in your throat D. Undergo a change in flavor

A

If a fast marble hits a random scatter of slow marbles, does the fast marble usually speed up or slow down? Which lose(s) kinetic energy and which gain(s) kinetic energy: the initially fast-moving marble or the initially slow ones? How do these questions relate to the direction of heat flow?

A fast-moving marble slows when it hits slower-moving marbles. It gives up some of its kinetic energy to the slower ones. Likewise with heat. Molecules with more kinetic energy that make contact with slower molecules give some of their excess kinetic energy to the slower ones. The direction of heat flow is from hot to cold. For both the marbles and the molecules, however, the total energy of the system before and after contact is the same

In desert regions that are hot in the day and cold at night, the walls of houses are often made of mud. Why is it important that the mud walls be thick?

A wall of appropriate thickness retains the warmth of the house at night by slowing the flow of thermal energy from inside to outside, and it keeps the house cool in the daytime by slowing the flow of thermal energy from outside to inside. Such a wall has "thermal inertia"

The temperature at which no further energy can be taken from a system

Absolute zero

How might you deduce the elemental composition of a star?

Aim a well-built spectroscope at the star and study its spectral patterns. In the late 1800's, this was done with our own star, the sun. Spectral patterns of hydrogen and some other known elements were observed, in addition to one pattern that could not be identified. Scientists concluded that this unidentified pattern belonged to an element not yet discovered on Earth. They named this element helium after the Greek work for "sun", helios

Which of these do not emit radiant energy: a) the sun, b) lava from a volcano, c) red-hot coals, d) a textbook?

All of these emit radiant energy---even a textbook, which like the other substances listed, has a temperature. According to the rule f ~ T, the book therefore emits radiation whose peak frequency f is quite low compared with the radiation frequencies emitted by the other substances. Everything with any temperature above absolute zero emits radiant energy.

Why are atoms invisible?

An individual atom is smaller than the wavelengths of visible light and so is unable to reflect light. Atoms are invisible, therefore, because visible light passes right by them. The atomic images generated by scanning probe microscopes are not photographs taken by a camera. Rather, they are computer renditions generated from the movements of an ultrathin needle

In the process of water vapor condensing in the air, the slower-moving molecules are the ones that condense. Does condensation warm or cool the surrounding air?

As slower-moving molecules are removed from the air, there is an increase in the average kinetic energy of molecules that remain in the air. Therefore, the air is warmed. The change of phase is from gas to liquid, which releases energy

Because water is most dense at 4 degrees C, what happens to the cold water?

As water cools, it sinks until the entire pond is at 4 degrees C. Then, as water at the surface cools further, it floats on top and can freeze. Once ice is formed, temperatures lower than 4 degrees C can extend down into the pond

The mass of an element's atoms listed in the periodic table as an average value based on the relative abundance of the element's isotopes

Atomic mass

The dense, positively charged center of every atom

Atomic nucleus

A count of the number of protons in the atomic nucleus

Atomic number

Heat energy travels from A. An object that has a greater amount of thermal energy to an object with lower thermal energy B. An object that has a higher temperature to an object with lower temperature C. Both of these D. None of these

B

Heat is simply another word for A. Radiant energy B. Thermal energy that flows from hot to cold C. Temperature D. Thermal energy

B

How does the wave model of electron orbiting the nucleus account for the fact that the electrons can have only discrete energy values? A. Electrons are ale to vibrate only at particular frequencies B. When an electron wave is confined, it is reinforced only at particular frequencies C. The energy values of an electron occur only where its wave properties have a maximum amplitude D. The wave model accounts for the shells that an electron may occupy, not its energy levels

B

How many electrons are there in in the third shell of sodium, Na (atomic number 11)? A. None B. One C. Two D. Three

B

If an atom has 43 electrons, 56 neutrons, and 43 protons, what is its approximate atomic mass? What is the name of this element? A. Atomic mass, 137 amu; barium B. Atomic mass, 99 amu; technetium C. Atomic mass, 99 amu; radon D. Atomic mass, 142 amu; einsteinium

B

In the mountains, water boils 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

B

The specific heat capacity for aluminum is more than twice that of copper. If equal quantities of heat are given to equal masses of aluminum and copper, the metal that more rapidly increases in temperature is A. Aluminum B. Copper C. Neither of these; that is, both will increase in temperature at the same rate D. None of these

B

The temperature of boiling water is A. 212°F B. Both C. 100°C

B

Thermal convection is linked most closely to A. Radiant energy B. Fluids C. Insulators D. All of these

B

Transparency of the atmosphere is lowest for radiation of A. Visible light B. Infrared light C. Ultraviolet light

B

When steam changes phase to water, it A. Absorbs energy B. Releases energy C. Neither absorb nor releases energy D. Becomes more conducting

B

Which of the following statements best describes an element? A. A material that is pure B. A material consisting of only one type of atom C. A material that has consistent chemical properties D. A material with more than one type of atom E. A material that has consistent physical properties

B

Your garage gets messier day by day. In this case, entropy is A. Decreasing B. Increasing C. Hanging steady D. None of these

B

Bermuda is close to North Carolina, but, unlike North Carolina, it has a tropical climate year-round. Why?

Bermuda is an island. The surrounding water warms it when it might otherwise be too cold, and cools it when it might otherwise be too warm

A rapid state of evaporation that takes place within the liquid as well as at its surface. As with other evaporation, cooling of the liquid results

Boiling

Distinguish between mass number and atomic mass

Both terms include the word "mass" and so are easily confused. Focus your attention on the second word of each term, however, and you'll get it right every time. Mass number is a count of the number of nucleons in an isotope. An atom's mass number requires no units because it is simply a count. Atomic mass is a measure of the total mass of an atom, which is given in atomic mass units

A bimetallic strip used in thermostats relies on the fact that different metals have different A. Specific heat capacities B. Thermal energies at different temperatures C. Rates of thermal expansion D. All of these

C

A piece of iron and a cup of water both have the same temperature. If they are heated so the thermal energy of each doubles, A. Both will have the same temperature B. Not enough information C. The iron will have the higher temperature D. The water will have the higher temperature

C

A substance that heats up relatively quickly has a A. High or low specific heat capacity B. High specific heat capacity C. Low specific heat capacity

C

An object that absorbs energy well also A. Conducts well B. Convects well C. Radiates well D. None of these

C

If the same quantity of heat is added to both a 1-liter and a 2-liter container of water, the temperature change of water in the 1-liter container will be A. More than half but less than twice B. None C. Twice D. Half

C

One of the main reasons people can walk barefoot on red-hot coals of wood without burning their feet has to do with A. Low temperature of the coals B. Mind over matter techniques C. Low thermal conductivity of the coals

C

Planet Earth loses heat mainly by A. Conduction B. Convection C. Radiation D. All of these

C

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

C

The silver coating on the glass surfaces of a Thermos bottle reduces energy that is transferred by A. Friction B. Conduction C. Radiation D. None of the above E. Convection

C

Thermal energy is normally measured in units of A. Calories B. Joules C. Both of these D. Neither of these

C

Water at 4 degrees C will expend when it is slightly A. Cooled B. Warmed C. Both of these D. Neither of these

C

When a solid is changed to a liquid phase, the solid A. Releases energy B. Neither releases nor absorbs energy C. Absorbs energy

C

Which are older: the atoms in the body of an elderly person or those in the body of a baby A. The atoms in baby because this surely a trick question B. The atoms in an elderly person because they have been around much longer C. They are the same age, which is appreciably older than the solar system D. It depends on the individual

C

Which two laws of thermodynamics are statements of what DOESN'T happen? A. The first and the second B. The first and the third C. The second and the third D. None of these; that is, they all state what does happen

C

Would you use a physical model or a conceptual model to describe the following, respectively: the brain; the mind; the solar system; the beginning of the universe? A. Conceptual; physical; conceptual; physical B. Conceptual; conceptual; conceptual; conceptual C. Physical; conceptual; physical; conceptual D. Physical; physical; physical; physical

C

Strontium, Sr (number 38), is especially dangerous to humans because it tends to accumulate in calcium-dependent bone marrow tissues (calcium, Ca, number 20). This fact relates to the organization of the periodic table in that strontium and calcium are both A. Soluble in water B. Metals C. Made of relatively large atoms D. In group 2 of the periodic table

D

A representation of a system that helps us predict how the system behaves

Conceptual model

The change of phase from gas to liquid; the opposite of evaporation, which warms the material

Condensation

The transfer of thermal energy by molecular and electronic collisions within a substance

Conduction

The transfer of thermal energy in a gas or liquid by means of currents in the heated fluid

Convection

The elements copper, Cu; silver, Ag; and gold, Au, are three of the few metals that can be found naturally in their elements state. These three metals have found great use as currency and jewelry for a number of reasons, including their resistance to corrosion and their remarkable colors. How is the fact that these metals have similar properties reflected in the periodic table?

Copper (atomic number 29), silver (atomic number 47), and gold (atomic number 79) are all in the same group in the periodic table (group 11), which suggests they should have similar---though not identical---properties

Absolute zero corresponds to a temperature of A. 0 K B. -273° C C. Neither D. Both

D

Compared with terrestrial radiation, the radiation from the sun has a A. Longer wavelength B. Lower frequencies C. Both of these D. None of these

D

If all the molecules of a body remained part of that body, would the body have any odor? A. Yes, but only if that body is sweating B. No, because it would no longer be what it was C. Yes, because it would still release photons D. No, because there would be no molecules traveling to our nose

D

List the following atoms in order of increasing atomic size: thallium, Tl; germanium, Ge; tin, Sn; phosphorus, P A. Ge<P<Sn<Tl B. Tl<Sn<P<Ge C. Tl<Sn<Ge<P D. P<Ge<Sn<Tl

D

Microscopic slush in water tends to make the water A. Slipperier B. Warmer C. More dense D. Less dense

D

The moderate temperatures of islands throughout the world has mainly to do with water's A. High evaporation rate B. Vast supply of thermal energy C. Poor conductivity D. High specific heat capacity E. Absorption of solar energy

D

What would be the temperature of 40.0 g of 22°C water mixed with 60.0 g of 80°C water? A. 28.4°C B. 30.2°C C. 50.6°C D. 56.8°C

D

When an iron ring is heated, the hole becomes A. Smaller B. Neither C. No answer text provided D. Larger

D

When evaporation occurs in a dish of water, the molecules left behind in the water A. Are less energetic B. Have decreased average speeds C. Result in lowered temperature D. All of these

D

Whether one object is warmer than another object has most to do with A. Heat flow B. Molecular potential energy C. Masses of internal particles D. Molecular kinetic energy

D

Which of these properties describes a metal? A. Transparent B. Brittle C. Fragile D. Conducts heat very well E. Doesn't conduct electricity very well

D

Why are the atomic masses listed in the periodic table not whole numbers? A. Today's instruments are able to measure the atomic masses to many decimal places B. Scientists have yet to make the precise measurements C. That would be too much of a coincidence D. The atomic masses are average atomic masses

D

The following statement describes which subatomic particle best? It does not have an electrical charge. A. B and C B. An electron C. A and B D. A proton E. A neutron

E

Which element would have chemical properties the most similar to those of chlorine (Cl, atomic number 17)? A. O B. Na C. S D. Ar E. Br

E

Which of the following elements is a transition metal? A. xenon (Xe) B. Lead (Pb) C. Chlorine (Cl) D. Lithium (Li) E. Silver (Ag)

E

An extremely small, negatively charged subatomic particle found outside the atomic nucleus

Electron

Any material that is made up of only one type of atom

Element

The change in the thermal energy of a system plus the product of its pressure and volume

Enthalpy

The measure of energy dispersal of a system. Whenever energy freely transforms from one form to another, the direction of transformation is toward a state of greater disorder and, therefore, toward one of greater entropy

Entropy

The change of phase at the surface of a liquid as it passes to the gaseous phase

Evaporation

Wood is a better insulator than glass. Yet fiberglass is commonly used to insulate buildings. Why?

Fiberglass is a good insulator, many times better than glass, because of the air that is trapped among its fibers

A restatement of the law of energy conservation, usually as it applies to systems involving changes in temperature: the heat added to a system is equal to the system's gain in thermal energy plus the work that it does on its surroundings

First law of thermodynamics

The process of changing phase from liquid to solid, as from water to ice

Freezing

Rapidly boiling water has the same temperature as simmering water, both a 100 degrees C. Why, then, do the directions for cooking spaghetti often call for rapidly boiling water?

Good cooks know that the reason for the rapidly boiling water is not higher temperature, but simply a way to keep the spaghetti from sticking together

A vertical column in the periodic table, also know as a family of elements

Group

The thermal energy that flows from a substance of higher temperature to a substance of lower temperature, commonly measured in calories or joules

Heat

The amount of energy transfer needed to change a unit of mass of any substance from sold to liquid (and vice versa). For water, this is 334 J/g (or 80 cal/g)

Heat of fusion

The amount of energy transfer needed to change a unit of mass of any substance from liquid to gas (and vice versa). For water, this is 2256 J/g (or 540 cal/g)

Heat of vaporization

Explain why you can hold your fingers beside the candle flame without harm, but not above the flame

Hot air travels upward by air convection. Because air is a poor conductor, very little energy travels sideways to your fingers

If a good absorber of radiant energy were a poor emitter, how would its temperature compare with the temperature of its surroundings?

If a good absorber were not also a good emitter, there would be a net absorption of radiant energy and the temperature of the absorber would remain higher than the temperature of the surroundings. Things around us approach a common temperature only because good absorbers are, by their nature, also good emitters

Which are larger: atoms of cesium, Cs (atomic number 55), or atoms of radon, Rn (atomic number 86

In any one period, all atoms to the left are larger than those to the right. Accordingly, cesium is positioned at the far left of period 6. So cesium is larger than radon (radon is positioned at the far right of period 6.

What is the term used in mechanics to signify the resistance of an object to a change in its state of motion

Interia

Any member of a set of atoms of the same element whose nuclei contain the same number of protons but different numbers of neurons

Isotopes

You apply a flame to 1 L of water for a certain time and its temperature rises by 2 degrees C. If you apply the same flame for the same time to 2 L of water, by how much does its temperature rise?

Its temperature rises by only 1 degree C, because 2 L of water contains twice as many molecules, and each molecule receives only half as much energy on the average. So the average kinetic, and thus the temperature, increases by half as much

The process of changing phase from solid to liquid, as from ice to water

Melting

Which is larger: a Celsius degree or a kelvin

Neither. They are equal

Any electrically neutral subatomic particle of the atomic nucleus

Neutron

The rate of heat loss or transfer of heat from a warm object is proportional to the temperature difference between the object and its surroundings. Rate of cooling - Delta T

Newton's law of cooling

Would evaporation be a cooling process if the escaping molecules had the same average energy as those left behind?

No. A liquid cools only when more energetic molecules escape. This is similar to billiard balls that gain speed at the expense of others that lose speed. Those that leave (evaporate) are gainer, while losers remain behind and lower the temperature of the water

Because a hot cup of tea loses thermal energy more rapidly than a lukewarm cup of tea, would it be correct to say that a hot cup of team will cool to room temperature before a lukewarm cup of tea will?

No. Although the rate of cooling is greater for the hotter cup of tea, it has further to cool to reach thermal equilibrium. The extra time is equal to the time it takes to cool to the initial temperature of the lukewarm cup of tea. Cooling rate and cooling time are not the same thing

Do atoms really consist of shells that are depicted in the shell model?

No. The shell model is not a depiction of the "appearance of an atom". Rather, it is a conceptual model that allows us to account for observed behavior. An atom, therefore, does not actually contain a series of concentric shells; it merely behaves as though it does

Because boiling is a cooling process, would it be good idea to cool your hot, sticky hands by dipping them into boiling water?

No. When we say boiling is a cooling process, we mean that the water left behind in the pot (and not your hands) is being cooled relative to the higher temperature it would attain otherwise. Because of the cooling effect of the boiling, the water remains at 100 degrees C instead of getting hotter.

Place a dish of water anywhere in your room. If the water level in the dish remains unchanged from one day to the next, can you conclude that no evaporation or condensation is occurring?

Not at all, for significant evaporation and condensation occur continuously at the molecular level. The fact that water level remains constant indicates equal rates of evaporation and condensation

Any subatomic particle found in the atomic nucleus. Another name for either a proton or a neutron

Nucleon

What must an electron be doing in order to have wave properties?

Particles of matter behave like waves by virtue of their motion. An electron must therefore be moving in order to have wave properties. In atoms, electrons move at speeds of about 2 million m/s, and so their wave nature is most pronounced

A horizontal row in the periodic table

Period

A chart in which all known elements are listed in order of atomic number

Periodic table

The molecular state of a substance: solid, liquid, gas, or plasma

Phase

A representation of an object on some convenient scale

Physical model

A small, discrete packet of light energy

Quantum

The idea that light energy is contained in discrete packets called quanta

Quantum hypothesis

The transfer of energy by means of electromagnetic waves

Radiation

Which has more energy: a photon of red light or a photon of infrared light?

Red light has higher frequency than in infrared light, which means a photon of red light has more energy than a photon of infrared light. Recall that a photon is a single discrete packet (a quantum) of radiant energy

Heat never spontaneously flows from a cold substance to a hot substance. Also, in natural processes, high-quality energy tends to transform, into lower-quality energy---order tends to disoreder

Second law of thermodynamics

A region of space about the atomic nucleus within which electrons may reside

Shell

The quantity of heat required to raise the temperature of a unit mass of a substance by 1 degrees C

Specific heat capacity

A device that uses a prism or diffraction grating to separate light into its color component

Spectroscope

Why is a steam burn more damaging than a burn by boiling water of the same temperature?

Steam burns do have to potential to cause more damage than scalding. The reason has to do with the latent heat of vaporization. This is the amount of heat energy necessary to change the phase or state of matter from liquid to gas. This energy is absorbed by the liquid, but does not change the temperature. When water goes from gas to liquid it is undergoing what is called a phase change. Phase changes require a lot more energy than just a temperature change. The energy required for water to go from a liquid to a gas is called the heat of vaporization. When steam hits your skin, a lot of energy will be released as it condenses into a liquid, undergoing a phase change. This energy release causes a much worse burn than if the same amount of boiling water were to hit your skin where it would decrease to your skins temperature, but would not have to go through a phase change. The loss of energy that is released from steam hitting your skin occurs quickly and in a small localized area, therefore causing damage to your cells.

The change of phase directly from solid to gas

Sublimation

A measure of the hotness of substances, related to the average translational kinetic energy per molecule in a substance, measured in degrees Celsius, degrees Fahrenheit, or kelvins

Temperature

The radiant energy emitted by Earth

Terrestrial radiation

A sample of hydrogen gas has a temperature of 0 degrees C. If the gas is heated until its hydrogen molecules have doubled their kinetic energy, what is its temperature?

The 0 degrees C gas has an absolute temperature of 273 K. Twice as much kinetic energy means that it has twice the absolute temperature, or two times 273 K. This would be 546 K, or 273 degrees C

Is the Bohr model of the atom a physical model or conceptual model?

The Bohr model is a conceptual model. It is not a scaled-up version of an atom, but instead is a representation that accounts for the atom's behavior

How many protons are there in an iron atom, Fe (atomic number 26)?

The atomic number of an atom and its number of proton are the same. Thus, there are 26 protons in an iron atom. Another way to put this is to say that all atoms that contain 26 protons are, by definition, iron atoms

Which would be more effective in heating the air in the room: a heating radiator painted black or silver?

The color of paint is a small factor, so either color can be used. That's because radiators do very little heating by radiation. Their hot surfaces warm surrounding air by conduction, the warmed air rises, and warmed convection currents heat the room. (A better name for this type of heater would be a convector). Now for "optimum efficiency", a silver painted radiator radiates less, becomes and remains hotter, and does a better job of heating the air

A basketball coach describes a playing strategy to her team by way of sketches on a game board. Do illustrations represent a physical model or a conceptual model?

The sketches are a conceptual model the coach uses to describe a system (the players on the court), with the hope of predicting an outcome (winning the game)

What was the precise temperature at the bottom of Lake Michigan on New Year's Eve in 1901?

The temperature at the bottom of any body of water that has 4 degrees C water in it is 4 degrees C at the bottom, for the same reason that rocks are at the bottom. Both 4 degrees C water and rocks are more dense than water at any other temperature. Water is a poor heat conductor, so if the body of water is deep and in a region of long winters and short summers, the water at the bottom is likely to remain a constant 4 degrees C year round

A farmer turns on the propane burner in his barn on a cold morning and heats the air to 20 degrees C (68 degrees F). Why does he still feel cold?

The walls of the barn are still cold. The farmer radiates more energy to the walls than the walls radiate back at him, and he feels chilly. (On a winter day, you are comfortable inside your home or classroom only if the walls are warm---not just the air)

What's inside the open spaces of the ice crystals shown in Figure 6.19? Is it air, water, vapor, or nothing?

There's nothing at all in the open spaces, which can be thought as empty space---a void. If there were air or vapor in the open spaces, the illustration should show molecules there---oxygen and nitrogen for air and H2O for water vapor

The total energy (kinetic plus potential) of the submicroscopic particles that make up a substance

Thermal energy

The study of thermal energy and its relationship to heat and work

Thermodynamics

Which raises the temperature of water more: adding 4.19 J or 1 calorie?

They have the same effect. This is like asking which is longer: a 1.61-km- long track or a 1-mi- long track. They're the same length, just expressed in different units

No system can reach absolute zero

Third law of thermodynamics

Which has a higher specific heat capacity: water or sand? in other words, which takes longer to warm in sunlight (or longer to cool at night)?

Water has the higher specific heat capacity. In the same sunlight, the temperature of water increases more slowly than the temperature of sand. And water cools more slowly at night. (Walking or running barefoot across scorching sand in daytime is a different experience from doing the same in the evening). The low specific heat capacity of sand and soil, as evidenced by how quickly they warm in the morning sun and how quickly they cool off at night, affects local climates

Why does a piece of watermelon stay cool for a longer time than sandwiches do when both are removed from a picnic cooler on a hot day?

Water in the melon has more "thermal inertia" than sandwich ingredients, and it resists changes in temperature much more. This thermal inertia is specific heat capacity

If we place poisons in a landfill, we alter the composition of the land. If we put a few milliliters of chlorine in a swimming pool, we alter the composition of the pool. How can we put billions of tons of greenhouse gases into the atmosphere without altering its composition?

We can't

Explain what is meant by saying a thermometer measures its own temperature.

When a thermometer reaches thermal equilibrium, the temperature of the thermometer and the substance it is measuring are the same. Therefore, the thermometer is essentially measuring its own temperature. Basically, because it is in thermal contact with something whose temperature we wish to know, energy will flow between the two until their temperatures are equal and thermal equilibrium is established.

Write a short paragraph distinguishing between conduction and convection. Give two examples of each.

While both conduction and convection are means of transferring heat, the important difference is the medium through which the heat travels. Conduction occurs when heat is transferred through solid objects, like a bar. For example, if a metal rod is held above a fire, the heat eventually travels the length of the rod, making it difficult to hold. The heat then transfers to the person or apparatus holding the rod. On the other hand, convection is the method of heat transferred through liquid or gasses, such as water or air. Heat transfer using convection is used in the oven in the kitchen, using radiating heat through the air in the oven to heat and cook the food. So basically, conduction is the transfer of thermal energy between neighboring molecules due to temperature, for example in a metal pot. Convection is the movement of molecules within fluids due to heat, for example in a microwave or hot water cylinder.

A friend claims there are atoms in his brain that were once in the brain of Albert Einstein. Is your friend's claim likely correct or nonsense?

Your friend is correct. In addition, there are atoms in your friend's and everyone else's body that were once a part of Einstein and everybody else, too. The arrangements of these atoms, however, are now quite different. What's more, the atoms of which you and your friend are composed will be found in the bodies of all the people on Earth who are yet to be