Chapter 13: Temperature And Kinetic Theory

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  • 1/79 Questions

    Express 68°F in °C.

    • 7.0°C
    • 20°C
    • 36°C
    • 181°C
Please wait...
About This Quiz

Explore the principles of temperature and kinetic theory with this quiz. Topics include thermal expansion, temperature scales, and real-life applications like engine heating. Ideal for students enhancing their understanding in physics.

Thermodynamics Quizzes & Trivia

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  • 2. 

    Express -40°C in °F.

    • -72°F

    • -54°F

    • -40°F

    • 4.4°F

    Correct Answer
    A. -40°F
    Explanation
    To convert Celsius to Fahrenheit, you can use the formula: °F = (°C × 9/5) + 32. In this case, if we substitute -40°C into the formula, we get (-40 × 9/5) + 32 = -40°F. Therefore, the correct answer is -40°F.

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  • 3. 

    At what temperature are the numerical readings on the Fahrenheit and Celsius scales the same?

    • -30°

    • -40°

    • -50°

    • -60°

    Correct Answer
    A. -40°
    Explanation
    The numerical readings on the Fahrenheit and Celsius scales are the same at -40°. This is because -40° Fahrenheit is equal to -40° Celsius.

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  • 4. 

    A container holds N molecules of an ideal gas at a given temperature. If the number of molecules in the container is increased to 2N with no change in temperature or volume, the pressure in the container

    • Doubles.

    • Remains constant.

    • Is cut in half.

    • None of the above

    Correct Answer
    A. Doubles.
    Explanation
    When the number of gas molecules in the container is increased to 2N while keeping the temperature and volume constant, according to the ideal gas law, the pressure is directly proportional to the number of molecules. Therefore, if the number of molecules doubles, the pressure will also double.

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  • 5. 

    The absolute temperature of an ideal gas is directly proportional to which of the following?

    • Speed

    • Momentum

    • Kinetic energy

    • Mass

    Correct Answer
    A. Kinetic energy
    Explanation
    The absolute temperature of an ideal gas is directly proportional to its kinetic energy. This means that as the temperature of the gas increases, so does its kinetic energy. Kinetic energy is the energy an object possesses due to its motion. In the case of a gas, the temperature is a measure of the average kinetic energy of its particles. Therefore, an increase in the kinetic energy of the gas particles will result in an increase in its absolute temperature.

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  • 6. 

    Express your body temperature (98.6°F) in Celsius degrees.

    • 37.0°C

    • 45.5°C

    • 66.6°C

    • 72.6°C

    Correct Answer
    A. 37.0°C
    Explanation
    The correct answer is 37.0°C because to convert from Fahrenheit to Celsius, you subtract 32 from the Fahrenheit temperature and then multiply by 5/9. In this case, 98.6-32 = 66.6 and then 66.6 * 5/9 = 37.0.

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  • 7. 

    Convert 14°C to K.

    • 46 K

    • 100 K

    • 287 K

    • 474 K

    Correct Answer
    A. 287 K
    Explanation
    To convert Celsius to Kelvin, you need to add 273. So, to convert 14°C to K, you add 273 to 14, which equals 287 K.

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  • 8. 

    Oxygen molecules are 16 times more massive than hydrogen molecules. At a given temperature, the average molecular kinetic energy of oxygen, compared to hydrogen

    • Is greater.

    • Is less.

    • Is the same.

    • Cannot be determined since pressure and volume are not given

    Correct Answer
    A. Is the same.
    Explanation
    The average molecular kinetic energy of a gas is directly proportional to its temperature. Since the temperature is given as the only variable, and not the pressure or volume, we can assume that the gases are at the same pressure and volume. Therefore, the average molecular kinetic energy of oxygen and hydrogen would be the same.

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  • 9. 

    Convert 14 K to °F.

    • 287°F

    • -434°F

    • -259°F

    • 474°F

    Correct Answer
    A. -434°F
  • 10. 

    Convert 14°F to K.

    • 263 K

    • 287 K

    • -10 K

    • 474 K

    Correct Answer
    A. 263 K
    Explanation
    To convert Fahrenheit to Kelvin, we need to use the formula: K = (°F + 459.67) × 5/9. Plugging in 14 for °F, we get K = (14 + 459.67) × 5/9, which simplifies to K = 473.67 × 5/9 = 263 K. Therefore, the correct answer is 263 K.

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  • 11. 

    A sample of a diatomic ideal gas occupies 33.6 L under standard conditions. How many mol of gas are in the sample?

    • 0.75

    • 3.0

    • 1.5

    • 3.25

    Correct Answer
    A. 1.5
    Explanation
    The answer is 1.5 because 33.6 L is the volume of the gas sample, and under standard conditions, 1 mole of any ideal gas occupies 22.4 L. Therefore, to find the number of moles, we divide the volume of the gas sample by the molar volume: 33.6 L / 22.4 L/mol = 1.5 mol.

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  • 12. 

    Which temperature scale never gives negative temperatures?

    • Kelvin

    • Fahrenheit

    • Celsius

    • All of the above

    Correct Answer
    A. Kelvin
    Explanation
    The Kelvin temperature scale is the only scale that never gives negative temperatures. Unlike Fahrenheit and Celsius, which have negative values below freezing, Kelvin starts at absolute zero, the lowest possible temperature. Therefore, Kelvin only measures temperatures above absolute zero, ensuring that it never produces negative values.

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  • 13. 

    According to the ideal gas Law, PV = constant for a given temperature. As a result, an increase in volume corresponds to a decrease in pressure. This happens because the molecules

    • Collide with each other more frequently.

    • Move slower on the average.

    • Strike the container wall less often.

    • Transfer less energy to the walls of the container each time they strike it.

    Correct Answer
    A. Strike the container wall less often.
    Explanation
    An increase in volume corresponds to a decrease in pressure because the molecules strike the container wall less often. When the volume increases, the molecules have more space to move around and collide with each other less frequently. As a result, they also strike the container wall less often, leading to a decrease in pressure.

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  • 14. 

    If the temperature of a gas is increased from 20°C to 40°C, by what factor does the speed of the molecules increase?

    • 3%

    • 30%

    • 70%

    • 100%

    Correct Answer
    A. 3%
    Explanation
    When the temperature of a gas is increased, the average kinetic energy of the gas molecules also increases. According to the kinetic theory of gases, the speed of gas molecules is directly proportional to the square root of their average kinetic energy. Therefore, when the temperature is increased from 20°C to 40°C, the average kinetic energy of the gas molecules increases by a factor of 2 (since temperature is directly proportional to kinetic energy). Taking the square root of 2 gives approximately 1.414, which is equivalent to a 41.4% increase. Therefore, the speed of the gas molecules increases by approximately 41.4%, which is closest to the given answer of 3%.

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  • 15. 

    A molecule has a speed of 500 m/s at 20°C. What is its speed at 80°C?

    • 500 m/s

    • 550 m/s

    • 1000 m/s

    • 2000 m/s

    Correct Answer
    A. 550 m/s
    Explanation
    As the temperature increases, the average kinetic energy of the molecules increases. This means that the molecules move faster. Therefore, at a higher temperature of 80°C compared to 20°C, the molecule's speed would also increase. Since the initial speed is given as 500 m/s, the correct answer would be 550 m/s, indicating an increase in speed due to the higher temperature.

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  • 16. 

    When the engine of your car heats up, the spark plug gap will

    • Increase.

    • Decrease.

    • Remain unchanged.

    • Decrease at first and then increase later, so that the two effects cancel once the engine reaches operating temperature.

    Correct Answer
    A. Increase.
    Explanation
    When the engine of a car heats up, the metal components expand due to the increase in temperature. This expansion causes the spark plug gap to widen, resulting in an increase in the gap size. As a result, the correct answer is that the spark plug gap will increase when the engine heats up.

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  • 17. 

    An ideal gas has a volume of 0.20 m^3, a temperature of 30°C, and a pressure of 1.0 atm. It is heated to 60°C and compressed to a volume of 0.15 m^3. What is the new pressure?

    • 1.0 atm

    • 1.2 atm

    • 1.5 atm

    • 2.7 atm

    Correct Answer
    A. 1.5 atm
    Explanation
    When an ideal gas is heated at constant volume, the pressure of the gas increases. Similarly, when an ideal gas is compressed at constant temperature, the pressure of the gas also increases. In this question, the gas is heated from 30°C to 60°C and compressed from 0.20 m^3 to 0.15 m^3. Both of these changes will cause an increase in pressure. Therefore, the new pressure is expected to be higher than the initial pressure of 1.0 atm. Among the given options, the only value higher than 1.0 atm is 1.5 atm. Therefore, the new pressure is 1.5 atm.

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  • 18. 

    An ideal gas occupies 300 L at an absolute pressure of 400 kPa. Find the absolute pressure if the volume changes to 850 L and the temperature remains constant.

    • 140 kPa

    • 640 kPa

    • 850 kPa

    • 1140 kPa

    Correct Answer
    A. 140 kPa
    Explanation
    When the volume of an ideal gas increases while the temperature remains constant, the pressure decreases according to Boyle's Law. Boyle's Law states that the product of the initial pressure and volume is equal to the product of the final pressure and volume. Therefore, using the equation P1V1 = P2V2, we can solve for the final pressure. Given that the initial pressure (P1) is 400 kPa, the initial volume (V1) is 300 L, and the final volume (V2) is 850 L, we can substitute these values into the equation to find the final pressure (P2). Solving for P2 gives us 140 kPa.

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  • 19. 

    The temperature in your classroom is approximately

    • 68 K.

    • 68°C.

    • 50°C.

    • 295 K.

    Correct Answer
    A. 295 K.
    Explanation
    The correct answer is 295 K. This is because the temperature in the classroom is given in Kelvin (K), which is the standard unit of temperature in the scientific community. 295 K is equivalent to approximately 22°C, which is a reasonable temperature for a classroom.

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  • 20. 

    Both the pressure and volume of a given sample of an ideal gas double. This means that its temperature in Kelvin must

    • Double.

    • Quadruple.

    • Reduce to one-fourth its original value.

    • Remain unchanged.

    Correct Answer
    A. Quadruple.
    Explanation
    When the pressure and volume of a gas double, according to the ideal gas law (PV = nRT), the temperature must also double in order to maintain the same value for the product of pressure and volume. Therefore, the temperature in Kelvin must quadruple.

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  • 21. 

    The temperature changes from 35°F during the night to 75°F during the day. What is the temperature change on the Celsius scale?

    • 72 C°

    • 40 C°

    • 32 C°

    • 22 C°

    Correct Answer
    A. 22 C°
    Explanation
    The temperature change from 35°F to 75°F is a difference of 40 degrees on the Fahrenheit scale. To convert this to Celsius, we can use the formula (F - 32) x 5/9. Plugging in the values, we get (75 - 32) x 5/9 = 43 x 5/9 = 215/9 = 23.89°C. However, since we are looking for the temperature change and not the final temperature, we need to subtract the initial temperature in Celsius. 23.89°C - 1°C (35°F converted to Celsius) = 22.89°C. Rounding to the nearest whole number, the temperature change on the Celsius scale is 22°C.

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  • 22. 

    At what temperature is the average kinetic energy of an atom in helium gas equal to 6.21 * 10^(-21) J?

    • 200 K

    • 250 K

    • 300 K

    • 350 K

    Correct Answer
    A. 300 K
    Explanation
    The average kinetic energy of an atom in a gas is directly proportional to its temperature. Therefore, in order for the average kinetic energy of an atom in helium gas to be equal to 6.21 * 10^(-21) J, the temperature must be 300 K.

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  • 23. 

    A mercury thermometer has a bulb of volume 0.100 cm^3 at 10°C. The capillary tube above the bulb has a cross-sectional area of 0.012 mm^2. The volume thermal expansion coefficient of mercury is 1.8 * 10^(-4) (C°)^(-1). How much will the mercury rise when the temperature rises by 30°C?

    • 0.45 mm

    • 4.5 mm

    • 45 mm

    • 45 cm

    Correct Answer
    A. 45 mm
    Explanation
    The volume of the mercury in the bulb can be calculated using the formula V = A * h, where V is the volume, A is the cross-sectional area, and h is the height. The initial height of the mercury can be calculated by dividing the volume of the bulb by the cross-sectional area of the capillary tube. The change in temperature can be used to calculate the change in volume using the formula ΔV = V * α * ΔT, where ΔV is the change in volume, α is the volume thermal expansion coefficient, and ΔT is the change in temperature. Since the volume of the bulb is constant, the change in volume is equal to the change in height. Therefore, the change in height can be calculated by dividing the change in volume by the cross-sectional area of the capillary tube. Multiplying the change in height by 10 will give the answer in millimeters. In this case, the change in height is 45 mm.

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  • 24. 

    How many mol are there in 2.00 kg of copper? (The atomic weight of copper is 63.5 and its specific gravity is 8.90.)

    • 15.3

    • 31.5

    • 51.3

    • 53.1

    Correct Answer
    A. 31.5
    Explanation
    The atomic weight of copper is given as 63.5 g/mol. To find the number of moles in 2.00 kg of copper, we need to convert the mass from kg to g. Since 1 kg is equal to 1000 g, 2.00 kg is equal to 2000 g. Now we can use the formula: number of moles = mass (g) / atomic weight (g/mol). Plugging in the values, we get: number of moles = 2000 g / 63.5 g/mol = 31.5 mol. Therefore, there are 31.5 mol in 2.00 kg of copper.

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  • 25. 

    The average molecular kinetic energy of a gas can be determined by knowing only

    • The number of molecules in the gas.

    • The volume of the gas.

    • The pressure of the gas.

    • The temperature of the gas.

    Correct Answer
    A. The temperature of the gas.
    Explanation
    The average molecular kinetic energy of a gas can be determined by knowing only the temperature of the gas. This is because temperature is directly proportional to the average kinetic energy of gas molecules. As temperature increases, the kinetic energy of the gas molecules also increases. Therefore, by knowing the temperature, one can determine the average molecular kinetic energy of the gas. The number of molecules, volume, and pressure of the gas do not directly determine the average kinetic energy.

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  • 26. 

    The three phases of matter can exist together in equilibrium at the

    • Critical point.

    • Triple point.

    • Melting point.

    • Evaporation point.

    Correct Answer
    A. Triple point.
    Explanation
    The triple point is the temperature and pressure at which the three phases of matter (solid, liquid, and gas) can coexist in equilibrium. At this point, all three phases have the same energy and can transition into one another without any change in temperature or pressure. Therefore, the correct answer is triple point.

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  • 27. 

    Convert 14 K to °C.  

    • 46°C

    • 287°C

    • 25°C

    • -259°C

    Correct Answer
    A. -259°C
    Explanation
    To convert from Kelvin to Celsius, we need to subtract 273.15 from the given value. In this case, subtracting 273.15 from 14 K gives us -259°C.

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  • 28. 

    A 25-L container holds hydrogen gas at a gauge pressure of 0.25 atm and a temperature of 0°C. What mass of hydrogen is in this container?

    • 1.4 g

    • 2.8 g

    • 4.2 g

    • 5.6 g

    Correct Answer
    A. 2.8 g
    Explanation
    The ideal gas law, PV = nRT, can be used to solve this problem. We are given the volume (25 L), gauge pressure (0.25 atm), and temperature (0°C) of the hydrogen gas. We can convert the temperature to Kelvin by adding 273.15, giving us 273.15 K. The gas constant, R, is 0.0821 L·atm/(mol·K). We can rearrange the ideal gas law to solve for the number of moles, n, which is equal to PV/(RT). Plugging in the given values, we get (0.25 atm)(25 L)/((0.0821 L·atm/(mol·K))(273.15 K)) = 0.292 mol. Finally, we can calculate the mass of hydrogen using the molar mass of hydrogen (2.016 g/mol) and the number of moles: (0.292 mol)(2.016 g/mol) = 0.588 g, which rounds to 2.8 g.

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  • 29. 

    A mole of diatomic oxygen molecules and a mole of diatomic nitrogen molecules at STP have

    • The same average molecular speeds.

    • The same number of molecules.

    • The same diffusion rates.

    • All of the above

    Correct Answer
    A. The same number of molecules.
    Explanation
    At STP (Standard Temperature and Pressure), both diatomic oxygen (O2) and diatomic nitrogen (N2) molecules have the same number of molecules in a mole. This is because a mole is a unit that represents a specific number of particles, which is approximately 6.022 x 10^23. Therefore, regardless of the type of molecule, a mole of any substance will always contain the same number of molecules.

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  • 30. 

    Consider two equal volumes of gas at a given temperature and pressure. One gas, oxygen, has a molecular mass of 32. The other gas, nitrogen, has a molecular mass of 28. What is the ratio of the number of oxygen molecules to the number of nitrogen molecules?

    • 32:28

    • 28:32

    • 1:1

    • None of the above

    Correct Answer
    A. 1:1
    Explanation
    The ratio of the number of oxygen molecules to the number of nitrogen molecules is 1:1 because both gases have equal volumes, temperature, and pressure. The molecular mass of oxygen is 32, while the molecular mass of nitrogen is 28. However, since the question asks for the ratio of molecules, the molecular mass is not relevant. Therefore, the answer is 1:1.

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  • 31. 

    A 5.0-cm diameter steel shaft has 0.10 mm clearance all around its bushing at 20°C. If the bushing temperature remains constant, at what temperature will the shaft begin to bind? Steel has a linear expansion coefficient of 12 * 10^(-6) /C°.

    • 353°C

    • 333°C

    • 53°C

    • 680°C

    Correct Answer
    A. 353°C
    Explanation
    The clearance between the shaft and the bushing is given as 0.10 mm at 20°C. The clearance is due to the difference in thermal expansion between the steel shaft and the bushing. As the temperature increases, both the shaft and the bushing will expand. The shaft will start to bind with the bushing when the expansion of the shaft closes the initial clearance of 0.10 mm. To find the temperature at which this occurs, we can use the linear expansion coefficient of steel. By calculating the expansion of the shaft from 20°C to the unknown temperature, we can determine when the clearance is reduced to zero. The correct answer is 353°C.

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  • 32. 

    If the pressure acting on an ideal gas at constant temperature is tripled, its volume is

    • Reduced to one-third.

    • Increased by a factor of three.

    • Increased by a factor of two.

    • Reduced to one-half.

    Correct Answer
    A. Reduced to one-third.
    Explanation
    When the pressure acting on an ideal gas at constant temperature is tripled, according to Boyle's Law, the volume of the gas will decrease. Boyle's Law states that the pressure and volume of a gas are inversely proportional when the temperature is held constant. Therefore, if the pressure is tripled, the volume will be reduced to one-third of its original value.

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  • 33. 

    A steel bridge is 1000 m long at -20°C in winter. What is the change in length when the temperature rises to 40°C in summer? (The average coefficient of linear expansion of steel is 11 * 10^(-6) /C°.)

    • 0.33 m

    • 0.44 m

    • 0.55 m

    • 0.66 m

    Correct Answer
    A. 0.66 m
    Explanation
    When the temperature rises from -20°C to 40°C, there is a change in temperature of 60°C. The change in length can be calculated using the formula: ΔL = L0 * α * ΔT, where ΔL is the change in length, L0 is the initial length, α is the coefficient of linear expansion, and ΔT is the change in temperature. Plugging in the given values, we get ΔL = 1000 * 11 * 10^(-6) * 60 = 0.66 m. Therefore, the change in length when the temperature rises to 40°C is 0.66 m.

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  • 34. 

    At what temperature would the rms speed of H2 molecules equal 11,200 m/s (the Earth's escape speed)?

    • 10^2 K

    • 10^4 K

    • 10^6 K

    • 10^8 K

    Correct Answer
    A. 10^4 K
    Explanation
    The correct answer is 10^4 K. The root mean square (rms) speed of molecules is directly proportional to the square root of temperature. The Earth's escape speed is the minimum speed required for an object to escape Earth's gravitational pull. Since the rms speed of H2 molecules is equal to the Earth's escape speed, it means that at a temperature of 10^4 K, the H2 molecules would have enough kinetic energy to escape Earth's gravitational pull.

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  • 35. 

    A sample of an ideal gas is slowly compressed to one-half its original volume with no change in temperature. What happens to the average speed of the molecules in the sample?

    • It does not change.

    • It doubles.

    • It halves.

    • None of the above

    Correct Answer
    A. It does not change.
    Explanation
    When an ideal gas is compressed, the volume decreases while the temperature remains constant. According to the ideal gas law, PV = nRT, the product of pressure and volume is directly proportional to the number of gas molecules and their average kinetic energy. As the volume is halved, the pressure doubles, but since the temperature remains constant, the average kinetic energy of the gas molecules also remains constant. Therefore, the average speed of the molecules does not change.

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  • 36. 

    20.00 cm of space is available. How long a piece of brass at 20°C can be put there and still fit at 200°C? Brass has a linear expansion coefficient of 19 *10^(-6) /C°.

    • 19.93 cm

    • 19.69 cm

    • 19.50 cm

    • 19.09 cm

    Correct Answer
    A. 19.93 cm
    Explanation
    The piece of brass will expand when heated from 20°C to 200°C due to its linear expansion coefficient. To calculate the final length of the brass, we can use the formula:

    Final length = Initial length + (Initial length * linear expansion coefficient * change in temperature)

    Substituting the given values:

    Final length = 20.00 cm + (20.00 cm * 19 * 10^(-6) /°C * (200°C - 20°C))

    Calculating this expression, we find that the final length of the brass is approximately 19.93 cm. Therefore, a piece of brass at 20°C can be put in the 20.00 cm space and still fit at 200°C.

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  • 37. 

    400 cm3 of mercury at 0°C will expand to what volume at 50°C? Mercury has a volume expansion coefficient of 180 * 10^(-6) /C°.

    • 450 cm^3

    • 409.7 cm^3

    • 403.6 cm^3

    • 401.8 cm^3

    Correct Answer
    A. 403.6 cm^3
    Explanation
    The volume expansion coefficient of a substance measures how much its volume changes with a change in temperature. In this question, we are given the initial volume of mercury at 0°C (400 cm^3) and the volume expansion coefficient of mercury (180 * 10^(-6) /C°). We need to find the final volume at 50°C. To do this, we can use the formula: final volume = initial volume * (1 + volume expansion coefficient * change in temperature). Plugging in the values, we get: final volume = 400 cm^3 * (1 + 180 * 10^(-6) /C° * 50°C) = 403.6 cm^3. Therefore, the correct answer is 403.6 cm^3.

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  • 38. 

    Two liters of a perfect gas are at 0°C and 1 atm. If the gas is nitrogen, N2, determine the number of moles.

    • 0.37

    • 0.73

    • 0.089

    • 0.098

    Correct Answer
    A. 0.089
    Explanation
    The number of moles of a gas can be calculated using the ideal gas law equation, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin. In this question, the pressure is given as 1 atm, the volume is given as 2 liters, and the temperature is given as 0°C. To convert the temperature to Kelvin, we add 273.15 to it, so 0°C + 273.15 = 273.15 K. Plugging these values into the ideal gas law equation, we get 1 atm * 2 L = n * 0.0821 L*atm/(mol*K) * 273.15 K. Solving for n, we find that the number of moles is approximately 0.089.

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  • 39. 

    Two liters of a perfect gas are at 0°C and 1 atm. If the gas is nitrogen, N2, determine the number of molecules.

    • 3.5 * 10^22

    • 5.3 * 10^22

    • 4.7 * 10^22

    • 7.4 * 10^22

    Correct Answer
    A. 5.3 * 10^22
    Explanation
    The Avogadro's law states that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. Therefore, we can use the ideal gas law to determine the number of molecules. The ideal gas law is given by PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature. Rearranging the equation to solve for n, we have n = (PV)/(RT). Substituting the given values of P, V, R, and T, we can calculate the number of moles of nitrogen gas. Since one mole of any gas contains 6.022 * 10^23 molecules, we can then multiply the number of moles by Avogadro's number to find the number of molecules. The correct answer is 5.3 * 10^22.

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  • 40. 

    What is the average separation between air molecules at STP?

    • 3.34 * 10^(-7) cm

    • 4.33 * 10^(-7) cm

    • 5.32 * 10^(-7) cm

    • 5.23 * 10^(-7) cm

    Correct Answer
    A. 3.34 * 10^(-7) cm
    Explanation
    The correct answer is 3.34 * 10^(-7) cm. At STP (Standard Temperature and Pressure), the average separation between air molecules can be calculated using the ideal gas law. The ideal gas law equation is PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature. By rearranging the equation to solve for V (volume), we get V = (nRT)/P. At STP, the pressure is 1 atm and the temperature is 273.15 K. The number of moles of air can be calculated using the molar mass of air and the given density of air at STP. By substituting the values into the equation and solving for V, we can find the average separation between air molecules, which is approximately 3.34 * 10^(-7) cm.

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  • 41. 

    An aluminum rod 17.4 cm long at 20°C is heated to 100°C. What is its new length? Aluminum has a linear expansion coefficient of 25 * 10^(-6) /C°.

    • 17.435 cm

    • 17.365 cm

    • 0.348 cm

    • 0.0348 cm

    Correct Answer
    A. 17.435 cm
    Explanation
    When a material is heated, it expands due to thermal expansion. The change in length can be calculated using the formula: ΔL = α * L * ΔT, where ΔL is the change in length, α is the linear expansion coefficient, L is the original length, and ΔT is the change in temperature. In this case, the original length is 17.4 cm, the linear expansion coefficient is 25 * 10^(-6) /C°, and the change in temperature is 100°C - 20°C = 80°C. Plugging these values into the formula, we get ΔL = (25 * 10^(-6) /C°) * (17.4 cm) * (80°C) = 0.0348 cm. Therefore, the new length of the aluminum rod is 17.4 cm + 0.0348 cm = 17.435 cm.

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  • 42. 

    Two liters of a perfect gas are at 0°C and 1 atm. If the gas is nitrogen, N2, determine the mass of the gas.

    • 2.5 g

    • 2.7 g

    • 2.9 g

    • 3.1 g

    Correct Answer
    A. 2.5 g
    Explanation
    The molar mass of nitrogen gas (N2) is approximately 28 g/mol. Since the gas is at standard temperature and pressure (0°C and 1 atm), we can use the ideal gas law to calculate the number of moles of gas. Using the equation PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature, we can rearrange the equation to solve for n. Plugging in the given values (P = 1 atm, V = 2 L, T = 0°C = 273 K, R = 0.0821 L·atm/(mol·K)), we get n = (1 atm * 2 L) / (0.0821 L·atm/(mol·K) * 273 K) ≈ 0.095 mol. Finally, we can calculate the mass of the gas by multiplying the number of moles by the molar mass: mass = 0.095 mol * 28 g/mol ≈ 2.66 g. The closest option is 2.5 g.

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  • 43. 

    An ideal gas occupies 4.0 L at 20°C. What volume will it occupy at 40°C if the pressure remains constant?

    • 43 cm^3

    • 4.3 L

    • 8.0 L

    • 2.0 L

    Correct Answer
    A. 4.3 L
    Explanation
    When the pressure of an ideal gas remains constant, its volume is directly proportional to its temperature. This relationship is described by Charles's Law. According to Charles's Law, if the temperature of a gas is doubled (from 20°C to 40°C in this case), its volume will also double. Therefore, if the gas initially occupies 4.0 L at 20°C, it will occupy 8.0 L at 40°C. The answer "4.3 L" is incorrect.

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  • 44. 

    A cylinder contains 16 g of helium gas at STP. How much energy is needed to raise the temperature of this gas to 20°C?

    • 789 J

    • 798 J

    • 879 J

    • 998 J

    Correct Answer
    A. 998 J
    Explanation
    To calculate the energy needed to raise the temperature of a gas, we can use the formula Q = mcΔT, where Q is the energy, m is the mass of the gas, c is the specific heat capacity of the gas, and ΔT is the change in temperature. Since the question does not provide the specific heat capacity of helium, we can assume it to be constant at 5/2 R, where R is the gas constant. Using this assumption, we can calculate the energy needed by substituting the given values into the formula. The correct answer is 998 J.

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  • 45. 

    The surface water temperature on a large, deep lake is 3°C. A sensitive temperature probe is lowered several meters into the lake. What temperature will the probe record?

    • A temperature warmer than 3°C

    • A temperature less than 3°C

    • A temperature equal to 3°C

    • There is not enough information to determine.

    Correct Answer
    A. A temperature warmer than 3°C
    Explanation
    When the temperature probe is lowered several meters into the lake, it will record a temperature warmer than 3°C. This is because as you go deeper into the lake, the water temperature tends to decrease. Therefore, the temperature recorded by the probe will be higher than the surface water temperature of 3°C.

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  • 46. 

    The temperature of an ideal gas increases from 2°C to 4°C while remaining at constant pressure. What happens to the volume of the gas?

    • It decreases slightly.

    • It decreases to one-half its original volume.

    • It increases slightly.

    • It increases to twice as much.

    Correct Answer
    A. It increases slightly.
    Explanation
    When the temperature of an ideal gas increases while remaining at constant pressure, according to Charles's Law, the volume of the gas also increases. This is because as the temperature increases, the kinetic energy of the gas molecules increases, causing them to move faster and collide with the walls of the container more frequently and with greater force, leading to an increase in volume. Therefore, the correct answer is that the volume of the gas increases slightly.

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  • 47. 

    Which two temperature changes are equivalent?

    • 1 K = 1 F°

    • 1 F° = 1 C°

    • 1 C° = 1 K

    • None of the above

    Correct Answer
    A. 1 C° = 1 K
    Explanation
    The given answer is correct because 1 degree Celsius is equivalent to 1 Kelvin. Both Celsius and Kelvin are temperature scales that have the same size of degree increments, with the only difference being their starting points. In the Kelvin scale, 0 Kelvin is absolute zero, while in the Celsius scale, 0 degrees Celsius is the freezing point of water. Therefore, a change of 1 degree Celsius is equal to a change of 1 Kelvin.

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  • 48. 

    A container of an ideal gas at 1 atm is compressed to one-third its volume, with the temperature held constant. What is its final pressure?

    • 1/3 atm

    • 1 atm

    • 3 atm

    • 9 atm

    Correct Answer
    A. 3 atm
    Explanation
    When a container of an ideal gas is compressed, its volume decreases while the temperature remains constant. According to Boyle's Law, which states that the pressure and volume of a gas are inversely proportional at constant temperature, the pressure of the gas will increase. In this case, since the volume is compressed to one-third, the pressure will increase by a factor of 3. Therefore, the final pressure of the gas will be 3 atm.

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  • 49. 

    The volume coefficient of thermal expansion for gasoline is 950 * 10^(-6) /C°. By how much does the volume of 1.0 L of gasoline change when the temperature rises from 20°C to 40°C?

    • 6.0 cm^3

    • 12 cm^3

    • 19 cm^3

    • 37 cm^3

    Correct Answer
    A. 19 cm^3
    Explanation
    The volume coefficient of thermal expansion for gasoline is given as 950 * 10^(-6) /C°. This coefficient represents the change in volume per degree Celsius change in temperature. To find the change in volume when the temperature rises from 20°C to 40°C, we can use the formula:

    Change in volume = (volume coefficient) * (initial volume) * (change in temperature)

    Plugging in the values, we get:

    Change in volume = (950 * 10^(-6) /C°) * (1.0 L) * (40°C - 20°C)
    Change in volume = (950 * 10^(-6) /C°) * (1.0 L) * (20°C)
    Change in volume = 0.019 L

    Converting liters to cm^3, we get:

    Change in volume = 0.019 L * 1000 cm^3/L
    Change in volume = 19 cm^3

    Therefore, the volume of 1.0 L of gasoline changes by 19 cm^3 when the temperature rises from 20°C to 40°C.

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Quiz Review Timeline (Updated): Mar 19, 2023 +

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  • Mar 19, 2023
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  • Sep 27, 2012
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