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Unit 3-6 notes pages 153-171
*STP=The standard temperature and pressure
*Standard Pressure= The pressure exerted by the atmosphere at sea level.
1 atmosphere (atm) =760 mmHg=101.3 Kilopascals (kPa)
*Standard temp.=The temperature at which water freezes.
0oC =32 oF = 273 K
Charles Law=(p.494) At constant pressure, the temperature and volume are directly proportional.
*Temperature equations are vertical! THINK ABOUT HEAT RISING!
V1 =V2
T1 T2
Temp must be in K for Charles Law!
i.e
What is the new volume at 20 K if the volume was 10 L at 40 K?
V1 =V2 10L= V2 Or 10L/40K=V2/20K V2=5L
T1 T2 40K 20K
When you cross multiply think of an infinity sign to give you the order. It always points to the answer.
Boyle’s Law=
At a constant temperature, the volume and pressure are inversely proportional.
THINK ABOUT PRESSURE FLATTENING THINGS!
V1(P1)=V2(P2)
What is the new volume at 20 atm if the volume was 5 L at 40 atm?
V1(P1)=V2(P2)
5 L(40 atm)=V2(20 atm)
5 L(40 atm)=V2(20 atm) V2=10 L
20 atm 20 atm
Popcorn song to listen to while demonstrating
Boyles laws with the syringes.
https://www.youtube.com/watch?v=mBDgfBunNyc
*Ideal Gas Law PV = RnT
States that all gases at any pressure, volume, temperature, and # of moles will always equal this number.
*Ideal Gas Constant =(R)=8.31 kpa.l/mol.k
*Combined Gas Law = The combined expressions of the previous gas laws.
n=#OF MOLES
*Avagadro's Hypothesis =
Equal volumes of gases at the same temp and pressure contain equal # of atoms
At STP 1 mol of any gas has 6.022 X 1023 particles, and occupies a space of 22.4L
*Daltons Law of Partial Pressures=
The total pressure exerted by a mixture of gases is a result of the individual gas pressures
PTotal = P1 +P2 +P3
Ex.
What is the total pressure if 40 kpa of O2, 20 kpa of He and 25 kpa of CO2 are in a container?
40 kpa+ 20 kpa +25 kpa= 85 kpa
Kinetic theory- explanation of how particles in matter behave.
Melting point- temperature at which a solid begins to liquefy.
Heat of fusion- amount of energy required to change a substance from the solid phase to the liquid phase at its melting point.
(Energy needed to melt an object.)
Boiling point- temperature at which the pressure of the vapor in the liquid is equal to the external pressure acting on the surface of the liquid.
(temperature at which a liquid changes to a gas)
Heat of vaporization- amount of energy required for the liquid at its boiling point to become a gas
(Energy needed evaporate an object.)
Diffusion- spreading of particles throughout a given volume until they are uniformly distributed. (Movement from a high concentration to a low concentration.)
*Effusions= The escape of gases through tiny holes in a container
When two bodies of different masses have the same kinetic energy, the lighter body moves faster.
Grahms’ Law of diffusion=Smaller particles move faster than larger particles.
Helium
https://www.youtube.com/watch?v=CaMXHvGFGPw
Floating a ship in Sulfur Hexafluoride
https://www.youtube.com/watch?v=u19QfJWI1oQ
Helium Travels faster so it raises your pitch
https://www.youtube.com/watch?v=5wXzFZnIQm8
https://www.youtube.com/watch?v=FRKVQcbIByo
Plasma- matter consisting of positively and negatively charged particles
Thermal expansion- increase in the size of a substance when the temperature is increased
Buoyancy- ability of a fluid to exert an upward force on an object immersed in it
Real vs. Ideal gases
Real gases Ideal gases
Form liquids and solids. Always stay in gas state.
Have mass. Have no mass.
Occupy space. Atoms take up no space.
Tranfer energy on contact. Have perfectly elastic collisions.
**Real gases behave like Ideal gases at high temperature and low pressure.
PRESSURE= The force applied to one unit of surface area.
Pressure = Force/Area or P=F/A
THINK ABOUT STANDING ON ONE FOOT OR TWO!
Labels are:
Pressure is pascals =Force is Newtons/Area is m2
Example:
What is the pressure exerted if a force of 10 N is over 20 m2?
P = 10 N/(20 m2)
P = 0.5 pascals or Pa
1 kPa = 1000 Pa
Viscosity- resistance to flow by a fluid
*Newton(N)= The unit commonly used to express force.
At Sea level, for every kg, there is 9.8 N of force acting on the object.
Example:What is the force on a 20 kg object? Force=mass(Acceleration)
Mass in Kg X 9.8 N/kg
20 kg(9.8 N/kg)= 196 N
*Absolute zero= The lowest point on the Kelvin scale, at which all motion theoretically stops.(0 K OR -273 OC)
*Kinetic energy= The energy produced by the motion of the atoms.
Kinetic molecular theory =Postulates of gas behavior.
1. Gases consist of tiny particles.(atoms or molecules.)
2. Gas particles are in constant random motion.
3. Collisions of gases are elastic. (Kinetic energy is not lost when molecules collide.)
4. At any temperature, the individual molecules will have different amounts of kinetic energy.( Kinetic energy changes with temperature.)
Layers of the atmosphere
1. Troposphere=
Layer closest to the Earth. Most dense and contains most of the Earth’s gases. (Approximately 78 % N2, 21 % O2, and 1 % Ar, plus numerous other gases in trace amounts.)
2. Stratosphere=
The layer of atmosphere that contains the ozone layer. This layer is thin, cold until the U.V. light is absorbed, and contains little moisture.(Strato-Sun protection)
3. Mesosphere=
The coldest layer of the atmosphere and has high winds that reach 320 km/hr.
(Minnesota’s winters-cold and windy.)
4. Thermosphere =
The uppermost layer of the atmosphere that absorbs most solar radiation. This layer contains the ionosphere, which absorbs most gamma rays and X-rays. (Hottest layer.)
Archimedes’ principle= The relationship between buoyancy and the weight of the displaced fluid.
*Characteristic Property= A property used to identify and classify substances.
*Drag= The friction created as an object moves through a liquid or gas.
Bernoulli’s principle= The faster a fluid moves, the less pressure it exerts.
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