Scio.ly | University of Texas at Austin Invitational

Passage

C_s ice = 2.09 J/g K C_s water = 4.184 J/g K C_s steam = 2.03 J/g K ∆H_{fus, H2O} = 334 J/g ∆H_{vap, H2O} = 2260 J/g 760 Torr = 1 atm R = 8.314 J/mol ∙ K R = 0.08206 L ∙ atm/mol ∙ K R = 62.36 L ∙ torr/mol ∙ K

Part I. Answer questions 1-4 in the provided blanks.

PassageFor questions 1–4

Convert the following given temperatures into the desired units:

Question 1

1 pt

50°C → ____ K

Question 2

1 pt

100°F → ____ °C

Question 3

1 pt

90°R → ____ K

Question 4

1 pt

What is a Joule in SI base units?

Part II – Multiple Choice: Answer questions 5-30 on the bubble sheet provided starting with #5. Answers on the test packet will not be scored for the multiple choice section.

Question 5

1 pt

Given: ∆T = 100°C for a process. What would be an equivalent temperature change?

A. ∆T = 100°FB. ∆T = 100KC. ∆T = 32°FD. ∆T = 373K

Question 6

1 pt

You walk outside on a hot summer day, and immediately you feel the heat from the sun's rays on your face. Which of the following is the type of heat transfer you just experienced?

A. ConductionB. ConvectionC. RadiationD. IR

Question 7

1 pt

A bomb calorimeter tests samples under ____ conditions.

A. IsobaricB. AdiabaticC. IsolatedD. Isochoric

Question 8

1 pt

Which of the following best summarizes the First Law of Thermodynamics?

A. For any process, ∆S_{universe} > 0B. ∆E = q + wC. For a spontaneous process, ∆G < 0D. q = mc∆T

Question 9

1 pt

Which of the following scientists created the first open thermometer?

A. Galileo GalileiB. William ThompsonC. JouleD. Nicolas Carnot

PassageFor questions 10–12

For questions 10-12, consider the Carnot Cycle.

Question 10

1 pt

Which of the following is true for the first phase of the Carnot Cycle?

A. The process is isobaric.B. The process is isothermal.C. The process adiabatic.D. A & C

Question 11

1 pt

Which of the following is true for the second phase of the Carnot Cycle?

A. The process is isothermal.B. The process is adiabatic.C. There is a decrease in entropy of the systemD. B & C

Question 12

1 pt

In a Carnot engine, the heat transferred to the heat sink, or "refrigerator," is 400kJ, and the work done by the engine is 300kJ. What is the ratio of the temperature of the heat source to the temperature of the heat sink?

A. 4/3B. 3/7C. 7/3D. 7/4

Question 13

1 pt

What is the difference between the specific heat capacity and heat capacity?

A. The specific heat capacity is used for specific objects, while heat capacity is used only for pure elemental objects.B. The specific heat capacity is adjusted for the mass of the object, but the heat capacity of an object is not.C. The heat capacity of an object is adjusted for its mass, but the specific heat capacity is not.D. The heat capacity is used only for pure elemental objects, while the specific heat capacity is used for specific objects.

Question 14

1 pt

Which scientist introduced the concept of entropy?

A. Rudolf ClausiusB. Anders CelsiusC. Walther NernstD. William Thompson

Question 15

1 pt

A capped, standard test tube filled with a solution is an example of what type of system?

A. OpenB. IsolatedC. ClosedD. Depends on the material the test tube is made of

Question 16

1 pt

A chemist is using a bomb calorimeter with a heat capacity of 4900J/°C to measure the heat released from the combustion of butane gas. The calorimeter is filled with 1L of water. Before she combusted the sample, the initial temperature of the calorimeter was 25°C. After she combusted the sample, the temperature was 31°C. What was the total heat released by the sample?

A. 29.4kJB. 25.1kJC. 54.5kJD. 33.6kJ

Question 17

1 pt

Using the answer found in #16 and the energy produced per mole of butane combusted (1500kJ/mol), how many moles of butane did the chemist have in her sample?

A. 0.0196 molesB. 0.0167 molesC. 0.0363 molesD. 0.0224 moles

Question 18

1 pt

A piston compresses a gas mixture at 70°C and 2 atm to one-tenth of its original volume. What is the temperature of the air-gas mixture after it is compressed? Do not assume constant pressure.

A. 700°CB. 3430KC. 70°CD. Not enough information given

Question 19

1 pt

A sample of gas in an expandable container is heated such that its temperature doubles. What is the ratio of the volume of the gas after heating to the volume of the gas before heating?

A. 1B. 4/1C. 1/2D. 2/1

Question 20

1 pt

What would the ratio of the pressure of the gas after heating to the pressure of the gas before heating (use the same information in #19).

A. 1B. 4/1C. 1/2D. 2/1

Question 21

1 pt · select all that apply

For a process that is spontaneous at a temperature T, which of the following must be true? At T…

A. ∆G process < 0B. ∆S universe > 0C. ∆H < 0D. ∆S_{system} > 0

Question 22

1 pt

Consider a chunk of ice that has equilibrated with its surroundings. If T = 0°C and the P = 1 atm, which of the following must be true?

A. ∆G_{melting} < 0B. The system now consists of both solid and liquid states.C. ∆H_{melting} < 0D. ∆S surroundings > 0

Question 23

1 pt

The mass of a piece of ice is 50g with an initial temperature of -10°C. You crank the temperature up to 110°C, and the ice quickly melts and then becomes entirely steam. How much energy did the environment transfer to the chunk of ice?

A. 152,680 JB. 25,104 JC. 12,540 JD. 12, 180 J

Question 24

1 pt

Who created the first closed thermometer?

A. Lord KelvinB. Anders CelsiusC. Nicolas CarnotD. Daniel Fahrenheit

Question 25

1 pt

Which scientist was instrumental in the discovery of the First Law of Thermodynamics?

A. Nicolas CarnotB. James Prescott JouleC. James MaxwellD. William Thompson

Question 26

1 pt

How did the scientist in #25 contribute to the First Law? (i.e. What did he discover?)

A. He found that heat can be transferred from a warmer object to a cooler object.B. He discovered convection currents.C. He discovered the first adiabatic process.D. He found that electrical energy can be converted into thermal energy, and vice-versa.

PassageFor questions 27–28

For 27 – 28, consider this system: CH_{4(g)} + 2O_{2(g)} → CO_{2(g)} + 2H₂O(g), ∆H = -882kJ/mol

Question 27

1 pt

Thermal energy is flowing ____ the system.

A. IntoB. Out ofC. Neither, the reaction is isothermal

Question 28

1 pt

The value of ∆S surroundings is most likely ____.

A. NegativeB. ZeroC. PositiveD. Not enough information to tell

Question 29

1 pt

At what temperature and pressure is CO₂ in all 3 states of matter?

A. -56.6°C, 1 atmB. -56.6°C, 5.1 atmC. 30°C, 10 atmD. None of these

Question 30

1 pt

Which of the following may explain why the slope of the border between liquid and solid H₂O is negatively sloped, while that of CO₂ is positively sloped?

A. Solid H₂O is denser than solid CO₂B. Solid H₂O is less dense than its liquid state, while solid CO₂ is denser than its liquid state.C. CO₂ will freeze at higher pressures than H₂O.D. CO₂ sublimes at STP, but H₂O does not.