Question 1

The first image shows an avocado with the number $$6.022 	imes 10$$^{23}$$ written on it. What is the significance of this number in physics?

Accepted Answer

It is the number of molecules in one mole, known as Avogadro's number.

Question 2

Given a sample containing $$1.204 	imes 10$$^{24}$$ molecules, how many moles does the sample contain? (Use Avogadro's number N_A = 6.022$$ 	imes $$10^{23})$$

Accepted Answer

$$2$$ moles

Question 3

A 10 $$m^3$$ balloon contains an ideal gas at $$100 K. If $$the temperature is reduced to $$50 K at $$constant pressure, what is the final volume of the balloon?

Accepted Answer

$$5$$ $$m^3$$

Question 4

Which equation correctly expresses the ideal gas law in terms of the number of particles $$N$$ and Boltzmann constant $$k$$?

Accepted Answer

$$PV = NkT$$

Question 5

Refer to the second image (Maxwell speed distribution). As temperature increases from $$300 K to$$ $$1200 K$$, what happens to the most probable speed and the root-mean-square speed of the gas molecules?

Accepted Answer

Both the most probable speed and $$v_{rms}$$ increase.

Question 6

For a monatomic ideal gas, what is the average kinetic energy per particle at temperature $$T$$?

Accepted Answer

$$\frac{3}{2} k T$$

Question 7

A system is separated from its environment by an adiabatic wall. What does this mean?

Accepted Answer

No heat can flow between the system and environment.

Question 8

According to the zeroth law of thermodynamics, if object A is in thermal equilibrium with object C, and object B is also in thermal equilibrium with object C, what can be concluded?

Accepted Answer

Objects A and B are in thermal equilibrium with each other.

Question 9

The first law of thermodynamics is given by $$\Delta U = Q - W. If a $$system absorbs $$500 J of $$heat and does $$200 J of $$work, what is the change in internal energy?

Accepted Answer

$$300 J$$

Question 10

During an isochoric process, what is the work done by the system?

Accepted Answer

$$W = 0$$

Question 11

In an isothermal expansion of an ideal gas, which of the following is true?

Accepted Answer

The internal energy of the gas remains constant.

Question 12

For an adiabatic process involving a monatomic ideal gas, which equation correctly relates the work done by the system to the change in temperature?

Accepted Answer

$$W = \frac{3}{2} nR (T_0$ - T_f)$$

Question 13

A gas undergoes an isobaric expansion from $$V_0 to$$ $$V_f at $$pressure $$P. $$What is the work done by the gas?

Accepted Answer

$$W = P(V_f - V_0$)$$

Question 14

Refer to the fourth image (pressure-volume graph). What does the area under the curve between points X and Y represent?

Accepted Answer

The work done on the system.

Question 15

A person jogs for 1 hour with a power output of $$170 W $$and gives off $$4.2 	imes 10^5$ J of heat. How much internal energy is lost? (Use W = Pt$ and t = 3600$ s)

Accepted Answer

$$-10.3 	imes 10^5$ J

Question 16

If one banana provides $$100$$ Calories ($$1$$ Calorie $$= 4.186 	imes 10^3$ J), how many bananas are needed to replace 10.3$$ 	imes $$10^5 J of $$lost energy?

Accepted Answer

$$2.5$$ bananas

Question 17

Which of the following statements about the root-mean-square speed $$v_{rms} is $$correct?

Accepted Answer

$$v_{rms}$$ increases with increasing temperature.

Question 18

Which of the following best describes a diathermal wall?

Accepted Answer

It allows heat to flow between systems.

Question 19

A sample of gas has a mass $$M_{samp}$$ and molar mass $$M. $$What is the number of moles $$n in $$the sample?

Accepted Answer

$$n = \frac{M_{samp}}{M}$$

Thermodynamics, Ideal Gas Law, and Kinetic Theory: Study Notes- lecture 29

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