Q&A Hero

Q: In using the ideal gas law, the temperature Tmust be measured in: A) Celsius B) Kelvin C) Fahrenheit D) either Celsius or Kelvin E) any units as long as the correct values of kor Rare used

Q: What is the relationship between the ideal gas constant Rand the Boltzmann constant k? A) R= nk/N B) R= Nk/n C) R= n/Nk D) R= N/nk E) depends on the molar specific heat of the gas

Q: Over 1 cycle of a cyclic process in which a system does net work on its environment: A) the change in the pressure of the system cannot be zero B) the change in the volume of the system cannot be zero C) the change in the temperature of the system cannot be zero D) the change in the internal energy of the system cannot be zero E) none of the above

Q: In order that a single process be both isothermal and occur at constant pressure: A) one must use an ideal gas B) such a process is impossible C) a change of phase is essential D) one may use any real gas such as N2 E) one must use a solid

Q: A given mass of gas is enclosed in a suitable container so that it may be maintained at constant volume. Under these conditions, there can be no change in what property of the gas? A) Pressure B) Density C) Molecular kinetic energy D) Internal energy E) Temperature

Q: The pressures pand volumes Vof the five ideal gases,with the same number of molecules, are given below. Which has the highest temperature?A) p= 1 x 105Pa and V= 10cm3B) p= 3 x 105Pa and V= 6 cm3C) p= 4 x 105Pa and V= 4 cm3D) p= 6 x 105Pa and V= 2 cm3E) p= 8 x 105Pa and V= 2 cm3

Q: An ideal gas undergoes an isothermal process starting with a pressure of 2 x 105Pa and a volume of 6 cm3. Which of the following might be the pressure and volume of the final state?A) 1 x 105Pa and 10cm3B) 3 x 105Pa and 6 cm3C) 4 x 105Pa and 4 cm3D) 6 x 105Pa and 2 cm3E) 8 x 105Pa and 2 cm3

Q: An air bubble doubles in volume as it rises from the bottom of a lake (1000 kg/m3). Ignoring any temperature changes, the depth of the lake is: A) 21 m B) 0.76 m C) 4.9 m D) 10 m E) 0.99 m

Q: Use R= 8.2 x10-5m3,atm/mol.K and NA= 6.02x1023mol-1. The approximate number of air molecules in a 1 m3volume at room temperature (300 K) and atmospheric pressure is:A) 41B) 450C) 2.4 x 1025D) 2.7 x 1026E) 5.4 x 1026

Q: Oxygen (molar mass = 32 g) occupies a volume of 12 liters when its temperature is 20°C and its pressure is 1 atm. Using R= 0.082 liter.atm/mole.K, calculate the mass of the oxygen:A) 6.4 gB) 11 gC) 16 gD) 32 gE) 64 g

Q: A 2.0-m3weather balloon is loosely filled with helium at 1 atm (76 cm Hg) and at 27°C. At an elevation of 20,000 ft, the atmospheric pressure is down to 38 cm Hg and the helium has expanded, being under no constraint from the confining bag. If the temperature at this elevation is -48°C, the gas volume is:A) 0.75 m3B) 1.3 m3C) 3.0 m3D) 4.0 m3E) 5.3 m3

Q: A sample of an ideal gas is compressed by a piston from 10 m3to 5 m3and simultaneously cooled from 273°C to 0°C. As a result there is:A) an increase in pressureB) a decrease in pressureC) a decrease in densityD) no change in volumeE) an increase in density

Q: An automobile tire is pumped up to a gauge pressure of 2.0 x105Pa when the temperature is 27°C. What is its gauge pressure after the car has been running on a hot day so that the tire temperature is 77°C? Assume that the volume remains fixed and take atmospheric pressure to be 1.013x105Pa.A) 1.6 x105PaB) 2.3 x105PaC) 2.5 x105PaD) 3.6 x105PaE) 8.6x105Pa

Q: It is known that 28 grams of a certain ideal gas occupy 22.4 liters at standard conditions (0°C, 1 atm). The volume occupied by 42 grams of this gas at standard conditions is:A) 14.9 litersB) 22.4 litersC) 33.6 litersD) 42 litersE) more data are needed

Q: Two identical rooms in a house are connected by an open doorway. The temperatures in the two rooms are maintained at different values. Which room contains more air? A) the room with higher temperature B) the room with lower temperature C) the room with higher pressure D) neither because both have the same pressure E) neither because both have the same volume

Q: 273 cm3of an ideal gas is at 0°C. It is heated at constant pressure to 10°C. It will now occupy:A) 263 cm3B) 273 cm3C) 278 cm3D) 283 cm3E) 293 cm3

Q: Air enters a hot-air furnace at 7°C and leaves at 77°C. If the pressure does not change each entering cubic meter of air expands to:A) 0.80 m3B) 1.25 m3C) 1.9 m3D) 7.0 m3E) 11 m3

Q: Evidence that a gas consists mostly of empty space is the fact that: A) the density of a gas becomes much greater when it is liquefied B) gases exert pressure on the walls of their containers C) gases are transparent D) heating a gas increases the molecular motion E) nature abhors a vacuum

Q: Platinum has a molar mass of 195 g/mol. If you have a ring that contains 2.3 g of platinum, how many moles does it contain? A) 0.012 mol B) 85 mol C) 450 mol D) 7.2 x 1021mol E) 1.4 x 1024mol

Q: How many molecules are in a sample of 10-3mol? A) 6.02 x 1018 B) 6.02 x 1020 C) 6.02 x 1022 D) 6.02 x 1023 E) cannot tell without knowing the molecular mass

Q: Avogadro's number is: A) 6.02 x 1018mol-1 B) 6.02 x 1020mol-1 C) 6.02 x 1022mol-1 D) 6.02 x 1023mol-1 E) 6.02 x 1024mol-1

Q: A slab of material has area A, thickness L, and thermal conductivity k. One of its surfaces (P) is maintained at temperature T1and the other surface (Q) is maintained at a lower temperature T2. The rate of heat flow from P to Q is:A) kA(T1- T2)/L2B) kL(T1- T2)/AC) kA(T1- T2)/LD) k(T1- T2)/(LA)E) LA(T1- T2)/k

Q: On a very cold day, a child puts his tongue against a fence post. It is much more likely that his tongue will stick to a steel post than to a wooden post. This is because: A) steel has a higher specific heat B) steel is a better radiator of heat C) steel has a higher specific gravity D) steel is a better heat conductor E) steel is a highly magnetic material

Q: A thermos bottle works well because: A) its glass walls are thin B) silvering reduces convection C) vacuum reduces heat radiation D) silver coating is a poor heat conductor E) none of the above

Q: Which of the following statements pertaining to a vacuum flask (thermos) is NOT correct? A) Silvering reduces radiation loss B) Vacuum reduces conduction loss C) Vacuum reduces convection loss D) Vacuum reduces radiation loss E) Glass walls reduce conduction loss

Q: Inside a room at a uniform comfortable temperature, metallic objects generally feel cooler to the touch than wooden objects do. This is because: A) a given mass of wood contains more heat than the same mass of metal B) metal conducts heat better than wood C) heat tends to flow from metal to wood D) the equilibrium temperature of metal in the room is lower than that of wood E) the human body, being organic, resembles wood more closely than it resembles metal

Q: The units of thermal conductivity might be:

Q: In the free expansion of a gas, A) the work done is zero but the heat transfer and change in internal energy may not be zero B) the heat transfer is zero but the work done and the change in internal energy may not be zero C) the change in internal energy is zero but the work done and the heat transfer may not be zero D) the work done, the heat transfer, and the change in internal energy all may not be zero E) the work done, the heat transfer, and the change in internal energy all are zero

Q: Of the following which might NOT be zero over one cycle of a cyclic process? A) the change in the internal energy of the substance B) the change in pressure of the substance C) the work done by the substance D) the change in the volume of the substance E) the change in the temperature of the substance

Q: In a constant-volume process with a gas, A) no heat is exchanged with the environment B) the internal energy of the gas does not change C) the gas does no work D) the pressure of the gas does not change E) the temperature of the gas does not change

Q: A system undergoes an adiabatic process in which its internal energy increases by 20 J. Which of the following statements is true? A) 20 J of work was done on the system B) 20 J of work was done by the system C) the system received 20 J of energy as heat D) the system lost 20 J of energy as heat E) none of the above are true

Q: In an adiabatic process: A) the energy absorbed as heat equals the work done by the system on its environment B) the energy absorbed as heat equals the work done by the environment on the system C) the energy absorbed as heat equals the change in internal energy D) the work done by the environment on the system equals the change in internal energy E) the work done by the system on its environment equals the change in internal energy

Q: In the first law of thermodynamics, the change in internal energy :A) is always positiveB) is always negativeC) cannot be zeroD) tends to increase if heat energy is transferred to the gas, and tends to decrease if the gas does work on its environmentE) tends to decrease if heat energy is transferred to the gas, and tends to increase if the gas does work on its environment

Q: In the first law of thermodynamics, the sign of the heat transfer Q: A) is positive if the system gives energy as heat to the environment and negative if it absorbs energy as heat from the environment B) is negative if the system gives energy as heat to the environment and positive if it absorbs energy as heat from the environment C) is always positive D) is always negative E) depends on the sign of the work being done

Q: In a certain process a gas ends in its original thermodynamic state. Of the following, which is possible as the net result of the process? A) It is adiabatic and the gas does 50 J of work B) The gas does no work but absorbs 50 J of energy as heat C) The gas does no work but rejects 50 J of energy as heat D) The gas rejects 50 J of heat and does 50 J of work E) The gas absorbs 50 J of energy as heat and does 50 J of work

Q: During an adiabatic process an object does 100 J of work and its temperature decreases by 5 K. During another process it does 25 J of work and its temperature decreases by 5 K. Its heat capacity for the second process is: A) 20 J/K B) 24 J/K C) 5 J/K D) 15 J/K E) 100 J/K

Q: According to the first law of thermodynamics, applied to a gas, the increase in the internal energy during any process: A) equals the heat input minus the work done on the gas B) equals the heat input plus the work done on the gas C) equals the work done on the gas minus the heat input D) is independent of the heat input E) is independent of the work done on the gas

Q: In the figure, what is the sign of the work done by the gas?A) positive if the transition is A -> B and negative if the transition is B -> AB) negative if the transition is A -> B and positive if the transition is B -> AC) positiveD) negativeE) zero (no work is done)

Q: In the figure, a gas undergoes a transition from point A to point B along the path shown. How much work is done by the gas?A) 10 kJB) 13 kJC) 23 kJD) -23 kJE) 0 kJ

Q: A gas: A) does positive work as it expands. B) does positive work as it contracts. C) does no work if it expands adiabatically. D) does negative work if it expands at constant pressure. E) may do either positive or negative work as it expands, depending on the heat transfer.

Q: Pressure vs. volume graphs for a certain gas undergoing five different cyclic processes are shown below. During which cycle does the gas do the greatest positive work? A) I B) II C) III D) IV E) V

Q: Of the following which might NOT be zero over one cycle of a cyclic process? A) the work done by the substance minus the energy absorbed by the substance as heat B) the change in the pressure of the substance C) the energy absorbed by the substance as heat D) the change in the volume of the substance E) the change in the temperature of the substance

Q: Fifty grams of ice at 0°C is placed in a thermos bottle containing one hundred grams of water at 6°C. How many grams of ice will melt? The heat of fusion of water is 333 kJ/kg and the specific heat of water is 4190 J/kg K.A) 7.5 gB) 2.0 gC) 8.3 gD) 17 gE) 50 g

Q: A certain humidifier operates by raising water to the boiling point and then evaporating it. Every minute 30 g of water at 20ï‚°C are added to replace the 30 g that are evaporated. The heat of fusion of water is333 kJ/kg, the heat of vaporization is 2256 kJ/kg, and the specific heat is 4190 J/kg K. How many joules of energy per minute does this humidifier require?A) 4800 J/minB) 18,600 J/minC) 24,600 J/minD) 77,700 J/minE) 10,100,000 J/min

Q: Steam at 100°C enters a radiator and leaves as water (at 80°C). Take the heat of vaporization to be 540 cal/g. Of the total energy given off as heat, what percent arises from the cooling of the water?A) 100%B) 54%C) 26%D) 14%E) 3.6%

Q: Ten grams of ice at -20°C is to be changed to steam at 130°C. The specific heat of both ice and steam is 0.5 cal/g °C. The specific heat of water is 1.00 cal/g K. The heat of fusion is 80 cal/g and the heat of vaporization is 540 cal/g. The entire process requires:A) 750 calB) 1250 calC) 6950 calD) 7450 calE) 7700 cal

Q: How many calories are required to change one gram of 0°C ice to 100°C steam? The latent heat of fusion is 80 cal/g and the latent heat of vaporization is 540 cal/g. The specific heat of water is 1.00 cal/g K.A) 100 calB) 540 calC) 620 calD) 720 calE) 900 cal

Q: Solid A, with mass M, is at its melting point TA. It is placed in thermal contact with solid B, with heat capacity CBand initially at temperature TB(TB>TA). The combination is thermally isolated. A has latent heat of fusion Land when it has melted has heat capacity CA. If A completely melts the final temperature of both A and B is:

Q: A metal sample of mass Mrequires a power input Pto just remain molten. When the heater is turned off, the metal solidifies in a time T. The specific latent heat of fusion of this metal is: A) P/MT B) T/PM C) PM/T D) PMT E) PT/M

Q: The formation of ice from water is accompanied by: A) absorption of energy as heat B) temperature increase C) decrease in volume D) an evolution of heat E) temperature decrease

Q: During the time that latent heat is involved in a change of state: A) the temperature does not change B) the substance always expands C) a chemical reaction takes place D) molecular activity remains constant E) kinetic energy changes into potential energy

Q: The heat of fusion of water is 79.5 cal/g. This means 79.5 cal of energy are required to: A) raise the temperature of 1 g of water by 1 K B) turn 1 g of water to steam C) raise the temperature of 1 g of ice by 1 K D) melt 1 g of ice E) increase the internal energy of 1 g of water by 1 J

Q: The three phases of matter are: A) new, half, full B) earth, air, fire C) static, kinetic, potential D) solid, liquid, gas E) plasma, vapor, fluid

Q: The heat capacity of object B is twice that of object A. Initially A is at 300 K and B is at 450 K. They are placed in thermal contact and the combination is isolated. The final temperature of both objects is: A) 300 K B) 350 K C) 400 K D) 450 K E) 600 K

Q: Object A, with heat capacity CAand initially at temperature TA, is placed in thermal contact with object B, with heat capacity CBand initially at temperature TB. The combination is thermally isolated. If the heat capacities are independent of the temperature and no phase changes occur, the final temperature of both objects is:

Q: The specific heat of lead is 0.030 cal/g °C. 300 g of lead shot at 100°C is mixed with 100 g of water at 70°C in an insulated container. The final temperature of the mixture is:A) 100°CB) 85.5°CC) 79.5°CD) 74.5°CE) 72.5°C

Q: The energy given off by 300 grams of an alloy as it cools by 50°C raises the temperature of 300 grams of water from 30°C to 40°C. The specific heat of the alloy is:A) 5.0cal/g .C°B) 0.10 cal/g .C°C) 0.15 cal/g .C°D) 0.20 cal/g .C°E) 0.50 cal/g.C°

Q: Take the mechanical equivalent of heat as 4 J/cal. A 10-gram bullet moving at 2000 m/s plunges into 1 kg of paraffin wax (specific heat 0.7 cal/g .°C). The wax was initially at 20°C. Assuming that all the bullet's energy heats the wax, its final temperature is:A) 20.14 °CB) 23.5 °CC) 20.006 °CD) 27.1 °CE) 48.6°C

Q: A cube of aluminum has an edge length of 20 cm. Aluminum has a density 2.7 times that of water (1 g/cm3) and a specific heat 0.217 times that of water (1 cal/g.C°). When the internal energy of the cube increases by 47000 cal its temperature increases by:A) 5 C°B) 10 C°C) 20 C°D) 100 C°E) 200 C°

Q: The same energy Qenters five different substances as heat. Which of these has the greatest specific heat? A) The temperature of 3 g of substance A increases by 10 K B) The temperature of 4 g of substance B increases by 4 K C) The temperature of 6 g of substance C increases by 15 K D) The temperature of 8 g of substance D increases by 5 K E) The temperature of 10 g of substance E increases by 10 K

Q: Two different samples have the same mass and temperature. Equal quantities of energy are absorbed as heat by each. Their final temperatures may be different because the samples have different: A) thermal conductivities B) coefficients of expansion C) densities D) volumes E) heat capacities

Q: The specific heat of a substance is:A) the amount of heat energy to change the state of one gram of the substanceB) the amount of heat energy per unit mass emitted by oxidizing the substanceC) the amount of heat energy per unit mass to raise the substance from its freezing to its boiling pointD) the amount of heat energy per unit mass to raise the temperature of the substance by 1°CE) the temperature of the object divided by its mass

Q: For constant volume processes the heat capacity of gas A is greater than the heat capacity of gas B. We conclude that when they both absorb the same energy as heat at constant volume: A) the temperature of A increases more than the temperature of B B) the temperature of B increases more than the temperature of A C) the internal energy of A increases more than the internal energy of B D) the internal energy of B increases more than the internal energy of A E) A does more positive work than B

Q: The heat capacity of an object is:A) the amount of heat energy to raise its temperature by 1°CB) the amount of heat energy to change its state without changing its temperatureC) the amount of heat energy per kilogram to raise its temperature by 1°CD) the ratio of its specific heat to that of waterE) the change in its temperature caused by adding 1 J of heat

Q: An insulated container, filled with water, contains a thermometer and a paddle wheel. The paddle wheel can be rotated by an external source. This apparatus can be used to determine: A) specific heat of water B) relation between kinetic energy and absolute temperature C) thermal conductivity of water D) efficiency of changing work into heat E) mechanical equivalent of heat

Q: A calorie is about: A) 0.24 J B) 8.3 J C) 250 J D) 4.2 J E) 4200 J

Q: Heat has the same units as: A) temperature B) work C) energy/time D) heat capacity E) energy/volume

Q: Heat is: A) energy transferred by virtue of a temperature difference B) energy transferred by macroscopic work C) energy content of an object D) a temperature difference E) a property objects have by virtue of their temperatures

Q: The thermal energy of an object is associated with: A) its kinetic energy B) its potential energy C) its inertia D) the random motions of its molecules E) the collective motions of its molecules

Q: A heat of transformation of a substance is: A) the energy absorbed as heat during a phase transformation B) the energy per unit mass absorbed as heat during a phase transformation C) the same as the heat capacity D) the same as the specific heat E) the same as the molar specific heat

Q: A gram of distilled water at 4ï‚°C:A) will increase slightly in weight when heated to 6°CB) will decrease slightly in weight when heated to 6°CC) will increase slightly in volume when heated to 6°CD) will decrease slightly in volume when heated to 6°CE) will not change in either volume or weight

Q: Metal pipes, used to carry water, sometimes burst in the winter because: A) metal contracts more than water B) outside of the pipe contracts more than the inside C) metal becomes brittle when cold D) ice expands when it melts E) water expands when it freezes

Q: The coefficient of expansion of a certain type of steel is 0.000012 per C°. The coefficient of volume expansion is:A) (0.000012)3(C°)-1B) (4/3)(0.000012)3(C°)-1C) 3 x0.000012 (C°)-1D) 0.000012 (C°)-1E) depends on the shape of the volume to which it will be applied

Q: The coefficient of linear expansion of steel is 11 x10-6per C°. A steel ball has a volume of exactly 100 cm3at 0°C. When heated to 100°C, its volume becomes:A) 100.33 cm3B) 100. 11 cm3C) 100.0011 cm3D) 100.0033 cm3E) none of these

Q: The coefficient of linear expansion of iron is 10-5per C°. The volume of an iron cube, 5 cm on edge, will increase by what amount if it is heated from 10°C to 60°C?A) 0.00375 cm3B) 0.1875 cm3C) 0.0225 cm3D) 0.0075 cm3E) 0.0625 cm3

Q: The mercury column in an ordinary medical thermometer doubles in length when its temperature changes from 95°F to 105°F. Choose the correct statement:A) the coefficient of volume expansion of mercury is 0.10 per F°B) the coefficient of volume expansion of mercury is 0.30 per F°C) the coefficient of volume expansion of mercury is (0.10/3) per F°D) the vacuum above the column helps to "pull up" the mercury this large amountE) none of the above is true

Q: The diagram shows four rectangular plates and their dimensions. All are made of the same material. The temperature now increases. Of these plates: A) the vertical dimension of plate 1 increases the most and the area of plate 1 increases the most B) the vertical dimension of plate 2 increases the most and the area of plate 4 increases the most C) the vertical dimension of plate 3 increases the most and the area of plate 1 increases the most D) the vertical dimension of plate 4 increases the most and the area of plate 3 increases the most E) the vertical dimension of plate 4 increases the most and the area of plate 4 increases the most

Q: An annular ring of aluminum is cut from an aluminum sheet as shown. When this ring is heated: A) the aluminum expands outward and the hole remains the same in size B) the hole decreases in diameter C) the area of the hole expands the same percent as any area of the aluminum D) the area of the hole expands a greater percent than any area of the aluminum E) linear expansion forces the shape of the hole to be slightly elliptical

Q: The figure shows a rectangular brass plate at 0°C in which there is cut a rectangular hole of dimensions indicated. If the temperature of the plate is raised to 150°C:A) xwill increase and ywill decreaseB) both xand ywill decreaseC) xwill decrease and ywill increaseD) both xand ywill increaseE) the changes in xand ydepend on the dimension z

Q: When the temperature of a copper penny is increased by 100 C°, its diameter increases by 0.17%. The area of one of its faces increases by:A) 0.17%B) 0.34%C) 0.51%D) 0.13%E) 0.27%