Physics Topic 10: Thermal Physics

1. State the equation of state for an ideal gas

PV=nRT R=8.31Jmol-1K-1P-pressure/V-volume/n-number of moles/R-gas constant/T-temperature

PV=RT/n

V=nP/RT

P=nRT/V

The ideal gas law equation is PV=nRT, where P is pressure, V is volume, n is number of moles, R is gas constant, and T is temperature. The correct equation describes the relationship between these variables for an ideal gas.

Explanation

The ideal gas law equation is PV=nRT, where P is pressure, V is volume, n is number of moles, R is gas constant, and T is temperature. The correct equation describes the relationship between these variables for an ideal gas.

2. Describe the difference between an ideal gas and a real gas

- Ideal Gas is always a solid at room temperature

- Real Gas does not undergo any phase changes under varying pressure

- Ideal Gas particles do not interact with each other

Ideal Gas Real Gas - Gas that obeys ideal gas law equation - In high pressure or low pressure, real gas condense to liquids and solidify - There are intermolecular forces present - Collisions are not perfectly elastic

An ideal gas is a theoretical gas that follows the ideal gas law, while a real gas behaves differently under high or low pressures due to intermolecular forces and non-perfectly elastic collisions.

Explanation

An ideal gas is a theoretical gas that follows the ideal gas law, while a real gas behaves differently under high or low pressures due to intermolecular forces and non-perfectly elastic collisions.

3. Describe the concept of the absolute zero of temperature and the Kelvin scale of temperature.

Absolute zero is the highest temperature, Kelvin scale measures volume

Absolute zero is the freezing point of water, Kelvin scale measures weight

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Absolute zero is the hottest possible temperature, Kelvin scale measures the speed of light

The concept of absolute zero refers to the point at which particles of a substance have minimal motion. The Kelvin scale of temperature is an absolute temperature scale where zero Kelvin is equal to absolute zero, which is approximately −273.15 degrees Celsius.

Explanation

The concept of absolute zero refers to the point at which particles of a substance have minimal motion. The Kelvin scale of temperature is an absolute temperature scale where zero Kelvin is equal to absolute zero, which is approximately −273.15 degrees Celsius.

4. Deduce an expression for the work involved in a volume change of a gas at constant pressure

W = nRT/ΔV

W = PΔV + nRT

W = PΔV

Refer to image

In this question, the correct answer is 'Refer to image' because the expression for the work involved in a volume change of a gas at constant pressure can vary depending on the specific context and equations involved, hence the need to refer to an image or specific information for the precise expression in this case.

Explanation

In this question, the correct answer is 'Refer to image' because the expression for the work involved in a volume change of a gas at constant pressure can vary depending on the specific context and equations involved, hence the need to refer to an image or specific information for the precise expression in this case.

5. Identify the first law of thermodynamics as a statement of the principle of energy conservation.

The first law of thermodynamics states that energy can be created or destroyed.

The first law of thermodynamics is a statement of the Law of Conservation of Mass.

The first law of thermodynamics is only applicable to closed systems.

Thefirst law of thermodynamics is a statement of the Law of Conservation of Energyin which the equivalence of work and thermal energy transfer is taken intoaccount

The first law of thermodynamics emphasizes the conservation of energy and the relationship between work and thermal energy transfer, rather than the creation or destruction of energy, conservation of mass, or being limited to closed systems.

Explanation

The first law of thermodynamics emphasizes the conservation of energy and the relationship between work and thermal energy transfer, rather than the creation or destruction of energy, conservation of mass, or being limited to closed systems.

6. Draw and annotate thermodynamics processes and cycles on P-V diagrams

A. Sketch and label electromagnetic waves on a P-V diagram

Refer to image

B. Plot and explain rotational kinetic energy on a P-V graph

C. Illustrate and define chemical reactions on a P-V chart

The incorrect answers provided do not align with the question which specifically asks for thermodynamics processes and cycles on P-V diagrams. Option A refers to electromagnetic waves which are not related to thermodynamics processes, Option B mentions rotational kinetic energy which is not typically represented on P-V diagrams, and Option C talks about chemical reactions which also do not directly correspond to the thermodynamics processes requested.

Explanation

The incorrect answers provided do not align with the question which specifically asks for thermodynamics processes and cycles on P-V diagrams. Option A refers to electromagnetic waves which are not related to thermodynamics processes, Option B mentions rotational kinetic energy which is not typically represented on P-V diagrams, and Option C talks about chemical reactions which also do not directly correspond to the thermodynamics processes requested.

7. Calculate from a P-V diagram the work done in a thermodynamic cycle.

Work done in a thermodynamic cycle is constant regardless of the shape of the P-V diagram.

Work is directly proportional to the change in pressure during the cycle.

Work done is independent of the volume of gas involved.

Work is the AREA of P vs. V graph where the area is the enclosed regionthat the graph and x-axis creates

When calculating work from a P-V diagram, it is important to consider the area under the curve of the graph, which represents the work done in the thermodynamic cycle. Work is not solely dependent on pressure or volume but rather the area enclosed by the graph and x-axis.

Explanation

When calculating work from a P-V diagram, it is important to consider the area under the curve of the graph, which represents the work done in the thermodynamic cycle. Work is not solely dependent on pressure or volume but rather the area enclosed by the graph and x-axis.

8. State the implication of the second law of thermodynamics regarding thermal energy transfer between regions of different temperatures.

Thermal energy can freely transfer between regions of varying temperatures.

The Second Law of Thermodynamics implies that thermal energy cannotspontaneously transfer from a region of low temperature to a region of hightemperature

The Second Law of Thermodynamics allows for thermal energy to flow from high temperature regions to low temperature regions.

Thermal energy transfer is not affected by the temperature difference between regions.

9. State the second law of thermodynamics in terms of entropy changes

The change in entropy of a system is independent of temperature

Change in entropy of a system when an amountof thermal energy Q is added to a system by a reversible process at constantabsolute temperature T is given by?S=,Q/TOr the total entropy of theuniverse is constantly increasing.

Entropy can be completely eliminated from a system

Entropy of a closed system will decrease when thermal energy is added