Gases and Work Flashcards
Pressure
W = Pressure/Area (P/A)
SI units for volume
m^3
1 m^3 = _____L
1000L
Work (W) cylinder
P x Delta Volume (Vfinal - V initial)
Calculating work, WORK DONE is always reported in
Joules
Ventilator doing work for the body, operating at a constant pressure of 600Pa is used to increases the volume of air in the lungs by 00ml
W= 0.300 J
What is a calorie defined as
The energy necessary to raise 1 g of water 1 degree Celsius
Food calories are _______ written as a “capitalized
C
1 Calorie = _______Joules
4.184 Joules
1 Kilocalories = ____Joules
4184 J
Kinetic energy is
the energy a mass has by virtue of being in motion
Formula for KE =
1/2 m x v^2
v^2
sq.root of 2KE/m
Potential Energy is stored by
virtue of position
NOT IMPORTANT Potential energy (PE) =
mgh
Internal Energy
The sum of all the kinetic and potential energies in particles in a system
Internal energy represented by letter
“U”
Thermodynamics, definition
4 laws, cite
Study of how energy is converted from one form to another and how it flows in and out of as system
Zeroth law of thermodynamics
if 2 system are in thermal equilibrium with a third system, then they are in thermal equilibrium with each other
First law of thermodynamics:
Change in U = Q + W
The change in internal energy of a system equals the sum of heat (Q) flowing in or out of the system; and the work done by or on the system
change U = Q-W (change U = heat- work)
When W is positive = (Q enters +)
When W is negative = (Q leaves gas -)
the system is absorbing energy or heat
the system is releasing energy or heat
Compressing a gas gives the gas molecules _________
energy since they are at a higher pressure than the surrounding atmosphere.
potential energy
How to add internal energy in a gas
Heat
Change in volume (compression –>exerting a force on a distance)
Work done by the gas is
Work done on the gas = work done by the gas
W is (definition)
joules of work energy done by or on the system
If Q > 0, process is endothermic: heat flows into system ___
[+Q]
If Q < 0, process is exothermic: heat flows out of system
[-Q]
If W < 0 work done by system on surroundings (expansion) ______
[-W]
If W > 0 work done on system by surroundings (compression) ____
[+W]
Second law
Entropy of the university is constantly increasing
If there is expansion, the system is doing work, energy is lost from the system so the sign for W is a _____
negative
Specific heat *** unimportant
the amount of heat per unit mass required to raised the temperature of something by 1 degree Celsius.
Formula of specific Heat (c)
c = Q / m (delta T)
This describes the change in velocity in time
Acceleration
This equals the product of an applied force times distance
Work
These kinds of quantities have both magnitude and direction
Vector
An object at rest remains at rest until a force act upon it
Newton’s First law
This is the ability to do work
Energy
The change in position with time is the
Velocity
This results from the acceleration of gravity action upon an object’s mass
Weight
This describes an object’s innate tendency to resist acceleration
INERTIA
Force divided by area gives
Pressure P= F/A
The specific heart of a good insulator should be ______WhY?
Large; less heat loss by the system
Work is
Force x distance
Define work
Expenditure of energy
Define work
Define energy
Expenditure of energy
The ability to do work
What is the formula for KE
1/2mv^2
The Change in internal energy of a system ( Delta U) is equal to
the sum of the heat processes (Q) that cause energy to flow into/out of the system and the work done by/on the system.
Delta U = Q + W
What is the endothermic process ? What does the system feels like Hot/cold? (change Q ? 0)
heat flows into the system from the surroundings . The system feels COLD. (change Q >0)
What is the exothermic process ? What does the system feels like Hot/cold? (change Q ? 0)
heat flows from the system into the surroundings . The system feels WARM. (change Q < 0)
Why does the temperature in the endothermic system drop?
- Heart flows in the system of endothermic process and contributes to the total internal energy of the system.
- Energy is necessary for an endothermic reaction to proceed and thus gets consumes in the chemical reaction. As molecules from the surroundings and the system lose KE (because it is being absorbed into the internal energy of the system) They slow down and get cooler. Thus the temperature drops.
The average KE of a smile is more closely related to
The heat content of the sample
What are the metric units for work?
Joules
1 J is ___/___
N/m
Work = formula
Force used x Distance moved
Work definition
Defined as a measurement of force displacing an object.
1 N (kg/m^2)
kg/ m^2
To solve a Work problem with weight in Kg?
change to Newton by using w=mg
KE =
½ mass x velocity ²
KE is expressed as J or _____
(kg/m²/s²)
Therefore, we can calculate
the work done by ________
expanding gases.
The gas will expand until ______ _____
the pressures are equalized.
1J for gas and pressure
Pa x m^3
1 C = ______kilocalories ____calories
1 ; 1000
When doing a problem, if there is expansion, the system _______. The sign for work of the system should be ______
is doing work and losing energy ; negative
W
When the problem stated that “x joules was absorbed, what should be inferred? It is ____ and should be _____
Heat flowed into the system (endothermic)
Q; positive
Remember for gas expansion or volume and pressure problems always convert L to
m^3
Under which of the following conditions is a gas least likely to be ideal?
High Pressure, Low temperature
Which of the following processes must always result in a net increase in internal energy of the system?
A system gains energy as heat and has work done on it by the surroundings.
