Lecture 6 - Effect of Heat on Liquids & Gases Flashcards
What IMF are in solids?
Solids have strong IMF
- they are closely packed with strong attractions
- low energy state
- when a liquid loses energy it becomes a solid
What IMF are in liquids?
- if you add energy to a solid the energy of the molecules increases and the distance between the molecules becomes larger and can overcome the IMF to become a liquid
- liquids are flow and take on the shape of their container, definite volume
- when a solid gains energy it becomes a liquid
What IMF are in gases?
Gases have high energy
- weak IMF
- almost no attraction to one another
What happens when heat (energy) is added to a substance?
The heat increases the distance between the molecules and overcome the IMF.
-molecules with more energy will move away from other molecules.
What type of motion is vibrational motion?
Bending, stretching
What type of motion is rotational motion?
rotating, spinning
What type of motion is translational motion?
Linear - from point A to point B
Is kinetic energy uniform through a liquid?
NO! some particles may have more KE (more movement) and some particles may have less KE (less movement) within the liquid. The particles with the most KE may be able to jump out of the liquid phase and into the gaseous phase.
Take home point: KE is not uniform for all molecules within a liquid.
What is the average KE of molecules in a liquid called?
Temperature
What is temperature?
the average KE of molecules in a liquid
What is the average KE of molecules in a liquid called?
Temperature
What is does it mean to say a volatile gas/liquid?
It means that it liquid can exist in the vaporized state.
You increase the vapor by increasing the heat.
Or you can increase the vapor by choosing a liquid with weaker IMF.
Are oxygen and nitrogen volatile gases?
No! They exist naturally as a gas and need to cooled to freezing temps to be a liquid form. therefore they are not volatile because they do not exist as both a liquid and a gas at the same temp.
What is the relationship between vapor pressure and IMF?
the weaker the IMF, the higher the Vapor Pressure
What is room temp?
20 degrees C
What is body temp?
37 degrees C
What is temperature?
-thermal state of a substance which determines whether it will give heat to another substance or receive heat from another substance.
What is temperature in terms of KE?
temperature is the average KE
Is temperature uniform throughout a surface?
No, heat can form a gradient with something that is cooler and something that is warmer. The warmer one has more KE because the temperature is higher and the KE energy of those molecules bouncing around can be transferred to a cooler substance if they can come in contact with one another
What is heat?
Heat is a form of energy that can be transferred from a hotter substance to a cooler substance.
- the energy is in the form of KE which resides in the molecules of a substance
- HEAT IS A THERMAL GRADIENT
How does heat flow?
Heat energy flows from an area of increased heat to an area of lower heat energy?
-this is called heat exchange
What is thermal conductivity?
- measurement of a substance’s ability to conduct (exchange) heat
- copper/bronze vaporizer housings have increased thermal conductivity
- some substances are better at conducting heat than others
How is heat transferred?
Heat is transferred by a molecule with a lot of KE (energy of motion) bumping into something with less KE and giving that molecule some of its energy –> transferring some energy
What is kinetic energy?
KE is the energy of motion
What is the formula for KE
KE = [Mass X velocity(squared)]/2
How does an increase in heat affect kinetic energy and velocity?
An increase in heat causes an increase in kinetic energy and therefore an increase in velocity
What is liquid in terms of flowing ability and shape?
- a liquid is a substance that flows freely but is of constant volume, having a consistency like that of water or oil
- takes the shape of the container
what type of motion is present in liquids?
translational motion
Rank the IMF from greatest to least for solids, liquids, and gases
greatest IMF = solids
middle IMF = liquids
least IMF = gases
Rank temperature (aka average KE) for solids, liquids, and gases from greatest to least
greatest KE/average temp = gases
middle KE/average temp = liquids
lowest KE/average temp = solids
Do liquids and gases take on the shape of their container?
Yes! Liquids and gases take the shape of their container and flow freely. The molecules are in translational motion but they are closer together in a liquid than in a gas.
Rank the KE from greatest to least for solids, liquids, and gases
KE greatest = gas
KE middle = liquid
KE least = solid
Do gases have a set volume?
no
Do gases take on the shape of their container?
yes
what type of motion is present in gases?
translational motion, from point A to point B
How strong are the IMF for gases?
weak IMF in gases
In comparison to solids and liquids, what is the temperature (average KE) of gases?
higher temperature aka higher KE compared to solids and liquids
What distinguishes a gas from the vapor?
FOR A GAS, ALL MOLECULES ARE IN THE GASEOUS STATE UNDER NORMAL CIRCUMSTANCES (ROOM TEMP, 1 ATM PRESSURE)
Is vapor a state of matter?
No, vapor is not a state of matter
What is vapor?
A vapor is a molecules from a liquid or solid that has jumped into the gaseous state.
Are vapors gases?
No - these vapors are not gases.
THEY ARE MOLECULES IN THE GASEOUS STATE.
Do gases and vapors have the same properties?
No, vapor molecules have slightly different properties from gas molecules despite the fact that they are both in the gaseous state.
What is the property that distinguishes vapors from gases? YOU NEED TO KNOW THIS!!!***
*!!!! A VAPOR IS THE PORTION OF A SUBSTANCE IN ITS GASEOUS STATE THAT CAN BE CONDENSED TO A LIQUID BY INCREASING THE PRESSURE WITHOUT REDUCING THE TEMPERATURE!!!
Vapor is an equilibrium between what two phases?
Vapor describes an equilibrium between molecules in the liquid and gas state.
How are vapors formed?
Vapors are formed when liquid (or solid) molecules gain enough KE to break IMF and move to a gaseous state.
What does volatile mean?
liquids that are volatile have molecules that more likely to move to the gaseous state
Do volatile liquids have an equilibrium?
Yes - volatile liquids have an equilibrium between the number of molecules in the liquid state and those in the gas state
What is vapor pressure?
vapor pressure is the ratio of substance molecules in the gas to liquid state
True or False: Vapors are gases.
FALSE! Vapors are molecules in the gaseous state. They are NOT gases.
When is equilibrium reached between a liquid and a gas?
- when molecules of a liquid evaporate in a closed container, they can’t escape back into a liquid
- when the rate of evaporation - the rate of condensation, the gas is at equilibrium with the liquid
What is vapor pressure?
the pressure the gas molecules exert at equilibrium is defined as the “vapor pressure”
Are the inhalation gases actually gases?
NO! they are volatile liquids with molecules in the gaseous state, they are vapors NOT gases.
is vapor pressure affected by atmospheric pressure?
NO! vapor pressure is not affected by atmospheric pressure. VAPOR PRESSURE IS A FUNCTION OF TEMPERATURE and IMF
-the vapor pressure of water at a fixed temperature is the same at sea level as it is on mount Everest
Is boiling point affected by atmospheric pressure?
Yes - boiling point is affected by atmospheric pressure. the boiling point would be lower as atmospheric pressure is lower at higher altitudes.
What two factors constitute the vapor pressure of a substance?
temperature and IMF factor into the vapor pressure
What is vaporization?
vaporization is the conversion of a volatile liquid to a vapor
what happens to the particles during vaporization?
the particles escape the liquid phase and go into the gaseous state
is the process of vaporization an endothermic or exothermic reaction?
endothermic process with a rate determined by the temperature of the liquid
IS VAPORIZATION A CHEMICAL OR PHYSICAL CHANGE?
VAPORIZATION IS A PHYSICAL CHANGE
when does vaporization stop?
vaporization ceases due to cooling unless heat is applied to the system
What three things determine the vapor pressure?
know this
- polarity of the liquid (increase polarity = decrease in VP because greater IMF)
- mass (increased mass = decreased VP)
- temperature (increased temp = increased VP)
Water at 20 degrees C has what VP in mmHg?
H2O at 20 degrees has a VP of 17.5 mmHg (OR temp, room temp)
Water at 37 degrees C has what VP in mmHg?
H2O at 37 degrees has a VP of 47 mmHg (body temp, alveoli temp, water vapor pressure of the lung)
Water at 100 degree C has what VP in mmHg?
H2O at 100 degrees C has a VP of 760 mmHg (this is the boiling point!!)
Anytime the temperature has a VP that equals 760 mmHg, what is that called?
the boiling point
the boiling point is the temperature at which the substance goes from liquid to gas and it is the temperature at which the VP = 760 mmHg
The higher the temp, the _________ the VP, the __________ the KE.
The higher the temp, the greater the VP, the greater the KE.
An increase in IMF, will _____________ the VP.
An increase in IMF, will decrease the VP because the IMF cannot be overcome at the given temp.
What is the latent heat of vaporization?
latent heat of vaporization is the amount of heat absorbed to convert a liquid to gas at its boiling point
- amount of heat absorbed to convert liquid to gas at boiling point
How many mmHg are in 1 atmosphere?
760 mmHg = 1 atmosphere
What is boiling point?
Boiling point is the temperature at which the vapor pressure of a liquid equals ambient pressure.
at the boiling point the entirety of the liquid enter the gas phase*
An increase in ambient pressure will ___________ the boiling point.
An increase in ambient pressure will increase the boiling point.
A decrease in ambient pressure will _________ the boiling point.
A decrease in ambient pressure will decrease the boiling point.
If you’re underwater do you have a greater or less ambient pressure?
If you’re underwater than your ambient pressure is greater than atmospheric and therefore it would take a greater amount of heat to reach the boiling point.
What is ambient pressure?
Ambient pressure refers to the pressure in the environment surrounding an organism
- aka ambient pressure is the pressure pushing on you depending on where you are
True or False: ambient pressure always equals atmospheric pressure.
False. Ambient can equal atmospheric pressure but it can also be less than or greater than atmospheric.
What is atmospheric pressure?
Atmospheric pressure is the total force of gas on earth’s surface.
aka atmospheric pressure doesn’t revolve around you, atmospheric pressure is the pressure on the earth.
When you go up to a higher atmosphere, the gas more or less dense?
At a higher atmosphere, there is less pressure and the air is less dense.
When you go down into the valley of mountains, is the gas more or less dense?
At a lower atmosphere, these is more pressure and the air is more dense.
can heat energy be transferred?
Yes - heat is a form of energy that can be transferred from a hotter substance to a cooler substance.
is heat a form of KE?
Yes - heat is a form of KE which resides in the molecules of a substance.
How does heat energy flow? from low to high or high to low?
Heat energy flows from high to low heat substances. this is called heat exchange.
What is thermal conductivity?
thermal conductivity is the measurement of a substances ability to conduct heat.
What are good conductor of heat?
copper and bronze
what is temperature?
temperature is the thermal state of a substance which determines whether it will give heat to another substance or receive heat from another substance.
what is the average KE of the molecules of a substance?
temperature is the average KE of a substance.
Is KE uniform throughout a substance?
NOOOOOO!!!!
Does temperature tell you how much thermal energy you have?
NO! temperature does not tell you how much thermal energy you have.
ex: 1 L at 80 degrees and 3 L at 80 degrees - which has more thermal energy –> the 3 L at 80 degrees
does temperature = thermal energy
NO. you can have two substances with the same temperature, the same KE, with different amount of thermal energy (1 L at 80 degrees vs 3 L at 80 degrees)
What conditions are part of STP?
- 0 degrees C, 273 K
- 1 atmosphere, 760 mmHg, 100 kPa
what is the temp at STP?
0 degrees C, 273 K
What is the pressure at STP?
1 atmosphere, 760 mmHg
How many degrees are between freezing and boiling in farenheit?
180 degrees are between freezing (32 degrees) and boiling (212 degrees)
How many degrees celsius are between freezing and boiling?
100 degrees are between freezing (0 C) and boiling 100 C)
How many degrees kelvin are between freezing and boiling?
100 degrees kelvin are between freezing (273 K) and boiling 373 K)
what is boiling temp in farenheit at 1 atm?
212 degree F
what is freezing temp in farenheit at 1 atm?
32 degrees F
what is boiling temp in celsius?
100 degree C
what is freezing temp in celsius?
0 degree C
what is boiling temp in Kelvin?
373 K
what is freezing temp in kelvin?
273 K
what is difference in boiling and freezing point in F?
180 degrees F
What is difference in boiling and freezing point in C?
100 degrees C
what is the difference in boiling and freezing points in Kelvin?
100 degrees K
what is absolute zero?
cannot reach absolute zero
- no movement of water particles
- 0 K, -273 C, -459.7 F
Formula to convert F to C
C = (F-32) X 0.56
Formula to convert C to F
F = (C X 1.8) + 32
Formula to convert C to K
K = C +273
What is an endothermic process?
- change in the state of matter requiring input of heat energy
- heat goes into the system
- energy flows into the system
What is an example of an endothermic process?
ice to water to vapor
-vaporization
is an endothermic process a chemical or physical change?
endothermic processes are physical changes that require the input of heat.
-energy flows into the system
What is an exothermic process?
- a change of state of matter requiring the output of heat energy
- energy flows out of the system
- heat is released
what is an example of an exothermic process?
- energy flows out of the system
- vapor to water to ice
is an exothermic process a chemical or physical change?
An exothermic process is a physical change.
- the movement of energy away from those molecules = outflow
What are the 4 methods for heat loss?
- convection
- conduction
- radiation
- evaporation
What is conDuction?
conDuction
-heat transferred from Direct contact from one point to another
What is clinical example of conDuction?
Patient placed in contact with a cold surface
What is conVection?
Vent like AC Vent
-conVection is when heat is transferred from fluid flowing over a solid while the temperature between the two are different
What is an example of convection?
air flowing over a patient’s body
- sauna = hot air flows over you and heat is transferred in and you get hot
- if air temp is less than body temp then air will absorb heat from the body surface = cooling
What is radiation?
Radiation = radiate like sunshine
- the transfer of heat through divergence in all directions from the center
- change the ATP bonds into energy & that energy can be radiated as heat through the skin from our bodies and bound and hit various gas molecules around us & will radiate throughout a particular direction
What is an example of radiation?
body heat will radiate to other objects in a room
What is evaporation?
is the conversion of a liquid to its vapor below the boiling temp of the liquid
What is an example of evaporation?
humidification of dry inspired air
- sweat = comes out at body temp but it is water on skin, the vaporization of sweat is heat leaving and we cool down.
What is the formula for pressure?
Pressure = force/area
Pressure is generated by….
Pressure is generated by KE, molecular weight and molecular motion
-gravity and energy are imparted to the particles
Pressure formula is =
pressure = force/area…
- the force applied to an object over its surface area
What direction is pressure applied?
pressure is applied perpendicular to the surface of the object
Is pressure a scalar quantity?
YES! Pressure is a scalar quantity.
Will an object move because pressure is applied to it?
No, an object will sit motionless at one atmosphere of pressure and will not be compelled to move simply because of the presence of pressure
With an increase in surface area, pressure will _________.
Increase in surface area = decrease in pressure
With an increase in force, pressure will __________.
Increase in force = increase in pressure.
With a decrease in surface area, pressure will _____________.
With a decrease in surface area, pressure will increase.
With a decrease in force, pressure will ___________.
With a decrease in force, pressure will decrease.
If density increases, pressure _________.
If density increases, pressure increases.
If density decreases, pressure ____________.
If density decreases, pressure decreases.
What is Pascal’s Law?
When an external pressure is applied to a confined fluid (gas or liquid), it is transferred to every point within the fluid.
Pressure has ____________, but not ___________. This is what makes it scalar.
Pressure has magnitude, but not direction. This what makes it scalar.
Force is a vector that has magnitude and direction.
Force is a vector that has magnitude and direction.
That is why force is different from pressure.
IS PRESSURE AFFECTED BY GRAVITY?
NO! Pressure is not affected by gravity.
Is pressure uniform throughout a fluid?
Yes, pressure is uniform through a fluid?
Is KE uniform throughout a fluid?
NO!
What is a torr?
A torr is a unit of measurement for pressure that is sufficient to support a 1 mm column of Hg at 0 C.
What does torr define?
Pressure
1 torr = _____ mmHg
1 torr = 1 mmHg.
1 atmosphere of pressure = ______ mmHg
1 atmosphere of pressure = 760 mmHg
1 atmosphere of pressure = ________ torr
1 atmosphere of pressure = 760 torr
1 atmosphere of pressure = _______ kPa
1 atmosphere of pressure = 100 kPa
1 atmosphere of pressure = _________ PSI
1 atmosphere of pressure = 14.7 PSI
1 atmosphere of pressure = ___________ cm H2O
1 atmosphere of pressure = 1000 cm H20
10,000 feet of altitude = __________ atmosphere
10,000 feet of altitude = 0.66 atmosphere
20,000 feet of altitude = _______ atmosphere
20,000 feet of altitude = 0.5 atmosphere
60,000 feet of altitude = _______ mmHg
60,000 feet altitude = 47 mmHg because water boils at 37 C at 60,000 feet up
33 ft H20 = _______ meters underwater = _______ atmospheres
33 ft H2O = 10 meters underwater = 2 atmospheres
66 ft H2O = ________ meters underwater = ________ atmospheres
66 ft H2O = 20 meters underwater = 3 atmospheres
99 ft H2O = ________ meters underwater = _______ atmospheres
99 ft H2O = 30 meters underwater = 4 atmospheres
What percent is O2 in the air?
21% oxygen in RA
What percent is N2 in the air?
79% nitrogen in RA
As altitude increases, then _______ decreases.
As altitude increases then atmospheric pressure decreases.
As altitude increases, the partial pressure of oxygen and nitrogen ________.
As altitude increases, the partial pressure of oxygen and nitrogen decrease.
What is dew point?
Dew Point is the temperature at which the water vapor in the air will begin to condensate and precipitate out.
A higher dew point means there is more or less moisture in the air?
A higher dew point means there is more moisture in the air.
A lower dew point means there is more or less moisture in the air?
A lower dew point means there is less moisture in the air.
For dew point, if there is more moisture in the air then the chances of water vapor molecules dropping into the liquid phase (condensing) is _________.
For dew point, if there is more moisture in the air than the chances of water vapor molecules dropping into the liquid phase (condensing) is greater.
Dew point is the temperature at which water vapor in the air will begin to do what two things?
Dew point is the temperature at which the water vapor in the air will begin to condensate and precipitate out.
If water vapor can condense at really high temps (70 F), then air must be more/less laden with water?
If water vapor can condense at really high temps (70 F), then air must be more laden with water.
A higher dew point means at a higher temp, water can still condense so the air must be pretty loaded with water.
A higher dew point means at a higher temp, water can still condense so the air must be pretty loaded with water.
atmospheric pressure is….
atmospheric pressure
-earth’s atmosphere is composed of air molecules
-these molecules are pulled towards the ground by gravity
-the weight of these air molecules pushes against us
at sea level there is enough atm air pressure to shift the mercury up the column a distance of 760 mm. Thus, atm pressure at sea level is 760 mmHg.
is the term barometric pressure the same as atmospheric pressure?
yes barometric pressure is the same as atmospheric pressure
what is ambient pressure?
ambient pressure is the pressure of the surrounding medium (i.e. gas, liquid) on you (or an object)
- if you are in air, the then ambient pressure = atm
- if you are underwater, then ambient pressure = atm + water (hydrostatic) pressure
if you are in the air, does ambient pressure = atmospheric pressure
YES, when you are in the air ambient pressure = atmospheric pressure
if you are underwater, then what does ambient pressure =
if you are underwater, then ambient pressure = atmospheric pressure + water (hydrostatic) pressure
What does Dalton’s law state?
Dalton’s law states the total pressure of a gas is equal to the sum of the pressures of the individual gases in a mixture
What does Dalton’s law state in formula form?
P1 + P2 + P3 +Pn = Ptotal
