Thermodynamics

Define the following forms of heat transfer: 1. Conduction 2. Convection 3. Radiation

1. Conduction is heat exchange by direct molecular interactions. 2. Convection is heat exchange by fluid movement. 3. Radiation is heat exchange by electromagnetic waves, and does not depend on matter.

Which of the following thermodynamic systems transfer matter? Transfer energy?

1. Open 2. Closed and Open 3. Isolated does neither

How do the initial length of an object and the amount it expands for a given temperature change relate to one another?

Expansion is a result of an increase in dimension at all points along an object. If an object is initially longer, it will experience a greater expansion because there is a direct relationship between length change and the initial length of an object.

True or False: The Kelvin scale is the most accurate measurement methods for temperature because it is based on absolute zero

False. Accuracy is related to an instrument, rather than the scale. In addition, Kelvin uses the same scale as Celsius, so there are no practical differences in terms of accuracy.

Draw a representative graph of the temperature of a solid object as it is heated and goes through two phase changes to become a gas

Increasing-plateau-increasing-plateau-increasing

Describe entropy on a macroscopic level and in statistical terms.

On a macroscopic level, entropy can be thought of as the tendency toward disorder. Statistically, entropy is the measure of the spontaneous dispersal of energy at a specific temperature, increasing the number of available microstates for a given molecule.

List at least five common state functions:

Pressure (P), density (p), temperature (T), volume (V), enthalpy (H), internal energy (U), Gibbs free energy (G), and entropy (S).

What is the difference between a state function and a process function?

State functions are variable independent from the path taken to achieves a particular equilibrium and are properties and are properties of a given system at equilibrium; they may be dependent on one another. Process functions define the path (or how the system got to its state) through variables such as Q (heat) or W (work)

Describe the relationship between internal energy, work, and heat.

The change in the internal energy of a system is equal to heat put into a system minus the work done by the system. This is the first law of thermodynamics.

What is the relationship between the entropy of a system and its surroundings for any thermodynamic process?

The entropy of a system and its surroundings will never decrease; it will always either remain zero or increase.

What is the zeroth law of thermodynamics?

The zeroth law of thermodynamics states that when two objects are both in thermal equilibrium with a third object, they are in thermal equilibrium with each other. By extension, no heat flows between two objects in thermal equilibrium.

What is the maximum distance that two objects can be from one another and still adhere to the zeroth law of thermodynamics?

While there may be a distance at which thermal equilibrium is impractical, there is no theoretical maximum distance. As long as two objects are in thermal contact and at the same temperature, they are in thermal equilibrium.

How is work calculated in P-V diagrams?

Work is the area under the curve (or within a closed loop)