Temperature and Pressure Concepts Flashcards
What is evaporation?
The process where a compound transitions from its liquid state to its gaseous state at a temperature below its boiling point
During evaporation, why do bubbles not form?
Vapor pressure is < atmospheric pressure
Explain the process of boiling.
Boiling occurs when vapor pressure equals atmospheric pressure. Boiling requires an open container
How are atmospheric pressure and boiling point related?
The two values are directly proportionate
What is specific heat?
The amount of heat required to increase the temperature of 1 gram of a substance by 1 degree Celsius
What is vapor pressure?
Pressure exerted on the walls of a closed container when molecules from a volatile liquid escape the liquid phase and enter the gas phase.
What is the relationship between vapor pressure and temperature?
The two are directly proportionate
The process by which a liquid is converted to a gas; requires energy (heat)
Vaporization
The number of calories required to vaporize 1mL of liquid
Heat of vaporization
The number of calories required to convert 1 gram of liquid to vapor without a temperature change in the liquid
Latent heat of vaporization
How do modern vaporizers avoid anesthetic cooling due to fresh gas flow?
- Using metals with high thermal conductivity (copper, bronze)
- Use a temperature compensation valve to modulate the amount of FGF that is directed into the vaporizing chamber (Sevo, Iso)
- Apply direct heat to the anesthetic liquid (Des)
What is an adiabatic process?
A process that occurs without gain or loss of energy (heat)
Gas stored at high pressure that is suddenly released escapes from its container into a vacuum –> it quickly loses speed as well as energy –> temperature falls
Joule- Thompson Effect
Identify the concept: An oxygen cylinder is quickly opened and becomes cool to the touch
Joule- Thompson Effect
Identify the concept: rapid compress of a gas intensifies its kinetic energy, causing the temperature to rise
Joule- Thompson Effect
The highest temperature where a gas can exist asa liquid; the temperature above which a gas cannot be liquefied regardless of the pressure applied to it
Critical temperature
What gases exist as liquids in their cylinders?
Nitrous oxide and carbon dioxide
Why do some gases exist as liquids in their cylinders?
Their critical temperatures are higher than room temperature
Critical temperature: 36.5C
Nitrous oxide
Critical temperature: 31C
Carbon dioxide
Critical temperature: -119C
Oxygen
Critical temperature: -140
Air
Critical temperature: -147
Nitrogen
The minimum pressure required to convert a gas to a liquid at its critical temperature
Critical pressure
Temperature at which a substance changes from a solid to liquid
Melting point
Temperature at which a substance shifts from a liquid to a gas
Boiling point
Convert Celsius to Kelvin
Kelvin = 273 + C
Convert Kelvin to Celsius
Celsius = K - 273
Convert Fahrenheit to Celsius
Celsius = (F - 32) x 5/9
Convert Celsius to Fahrenheit
Fahrenheit = (C x 1.8) + 32
What does Avogadro’s number signify?
1 mole of any gas is made up of 6.023 x 10^23 atoms
A mole of gas is equal to the molecular weight of that gas in grams.
How are area and pressure related?
The two are inversely proportionate
Convert mmHg to cmH2O
1mmHg = 1.36 cmH2O
Convert cmH2O to mmHg
1 cmH2O = 0.74 mmHg
