Chapter 7 Flashcards
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What is the minimum value on the Kelvin scale?
0 K
0 K is also known as absolute zero
What happens to particles of a substance as they approach absolute zero?
Particles slow down so much that they hardly move and their kinetic energy approaches 0 J
How do you convert from Kelvin to Celsius?
T_c = T_k - 273
How do you convert from Celsius to Kelvin?
T_k = T_c + 273
What is the melting point?
Temperature at which a solid changes to a liquid
What is the freezing point?
Temperature at which a liquid changes to a solid
What is the boiling point?
Temperature at which a liquid changes to a gas
What is the condensation point?
Temperature at which a gas changes to a liquid
True or False: The melting point and freezing point temperatures are equal.
True
True or False: The boiling point and condensation point temperatures are equal.
True
What is thermal energy?
Total potential and kinetic energy possessed by the particles of a substance
What is heat?
Transfer of thermal energy from a substance with a higher temperature to a substance with a lower temperature
What is thermal conduction?
Transfer of thermal energy that occurs when warmer objects are in physical contact with colder objects
What is thermal convection?
Transfer of thermal energy through a fluid that occurs when colder denser fluid falls and pushes up warmer less dense fluid
What is radiation in the context of thermal energy?
Movement of thermal energy as electromagnetic waves
What is specific heat capacity?
The amount of energy needed to raise the temperature of 1 kg of a substance by 1 °C
What is the specific heat capacity of water?
4.18 x 10^3 J/(kg *°C)
What is the specific heat capacity of vegetable oil?
2.0 x 10^3 J/(kg *°C)
What is the quantity of heat (Q)?
Total amount of thermal energy transferred from a warmer substance to a colder substance
What factors are considered in the quantity of heat calculation?
Mass (m), Specific heat capacity (c), Change in temperature (ΔT)
What is the equation for calculating quantity of heat?
Q = mcΔT
What happens to thermal energy when a warmer object comes in contact with a colder object?
Thermal energy is transferred from the warmer object to the colder object until thermal energy is evenly distributed
What is thermal expansion?
Increase in the volume of an object due to an increase in its temperature
What occurs during melting?
Absorbing thermal energy; particles move faster and farther apart
What occurs during freezing?
Releasing thermal energy; particles move slower and closer together
What occurs during boiling?
Absorbing thermal energy; particles gain enough kinetic energy to break away completely
What occurs during condensation?
Releasing thermal energy; particles bond together into a liquid
Fill in the blank: The principle of thermal energy exchange states that when a warmer object comes in contact with a colder object, thermal energy is ______.
transferred
What is a thermal conductor?
Material that allows thermal energy to pass through quickly and easily
What is a thermal insulator?
Material that does not allow thermal energy to pass easily
What is the best thermal insulator?
A vacuum
What happens to particles when they gain enough kinetic energy?
Particles gain enough kinetic energy to break away completely
This transition leads to the substance changing into a gas.
What occurs when a gas releases thermal energy?
Particles move slower and closer together, the substance cools, and its temperature decreases
Decreased particle speed strengthens forces of attraction between particles.
What is the condensation point?
The point at which bonds strengthen enough for the gas to become a liquid
At this stage, particles begin to cluster together.
What is the freezing point?
The point at which particles bond completely into a rigid structure, transitioning the substance into a solid
This process involves the release of thermal energy.
What is sublimation?
The direct change of a substance from solid to gas without becoming a liquid
An example is dry ice (solid carbon dioxide) turning into carbon dioxide gas.