Thermodynamics Section/Chapter Review(S)

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Thermodynamics
Section Review 9A:
1. Scientists believed that the caloric was a material but mainly that it was an invisible fluid consisting of self-repelling particles. Two examples include how gases expand according to Newton’s laws, and determining the speed of sound in air. 2. The first person to successfully challenge the caloric theory was Benjamin Thompson. Benjamin observed that a dull boring bit could generate more hat than needed to melt the entire cannon barrel. 3. The significance was that Joule discovered that heat was the equivalent of mechanical work, which made it a form of energy and not a material fluid. 4. 4.18 N⋅m, or J/g and multiplied by °C is the required energy to raise the temperature of a gram of water to 1 °C. 5. Internal energy is the total of all the kinetic energies of an object’s particles. Thermal energy on the other hand, is just the kinetic energy portion of internal energy. 6. Thermal energy can be measured only when it is transferred from one system to another. The change in temperature is what actually is measured. 7. Well, first of all, it’s big… and free! Also, it’s a star with limitless solar energy. A few challenges include the sky being cloudy from time to time, and… cost of the whole energy farm? 8. False.

Section Review 9B:
1. Well, in the first statement, the person is telling a description of the weather. So he/she is basically stating a qualitative statement. The second statement however, it’s a quantitative statement because the actual temperature measured is being stated. 2. The property of a thermometer that allows it to indicate temperature is the thermometric property. Examples include the thermal expansion of liquids or metals or on the change of an electrical property to detect temperature. 3. A fiducial point must be fixed, precisely measurable, and easily reproducible in appropriately equipped laboratories. The fiducial points for Fahrenheit are 32 °F and 212 °F. The fiducial points for Celsius are 0 °C and 100 °C. 4. One major advantage that the Celsius scale has is the metric basis. A disadvantage that they both share is the negative temperatures. 5. Well, the Kelvin scale resolves the problem in Question 4 because it contains only positive temperatures. 6. The temperature of the fiducial point on the Kelvin scale is 273.16 K. The triple point of water defines the Kelvin scale’s fiducial point. 7. Temperature changes can cause materials to expand or contract through thermal expansion. Temperature changes can also change electrical resistance. Finally, temperature changes the viscosity of liquids. 8. True.

9. Converted temperatures:
a. 38 °C
b. 72 °F
c. 37.0 °C
d. -40 °F
10. Converted temperatures:
a. T = 3925 K
b. tc = 801 °C
c. T = 234.3 K
d. tc = -269.0 °C
Section Review 9C:
1. Well, thermal energy is the sum of all kinetic energies of the atoms, molecules, ions, and subatomic particles in an object or substance. Heat is the quantity of thermal energy transferred between two systems. The difference is that thermal energy is a property of the system, whereas heat is not a property of the system. 2. The three ways that thermal energy can be transferred are through conduction, convection, and radiation. For conduction, diamonds are the best natural conductors of thermal energy. For convection, fluids are best – as thermal energy is carried from one location to another by a fluid. And finally, for radiation, a vacuum is best. 3. The Stirling generators will use the radiant energy transfer process. Also, I think that conduction inside the engines would be a useful process. 4. A material is a better insulator if its particles are bonded in an open, sponge-like structure or its electrons are held tightly to the atoms. 5. Well, heat capacity is the amount of thermal energy that must be transferred to change an object’s temperature by a single degree. Specific heat...
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