CHEMISTRY April 17 th, 2012. Brainteaser FRIDAY 4/20/12 Tell me how your are going to explain what...
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Transcript of CHEMISTRY April 17 th, 2012. Brainteaser FRIDAY 4/20/12 Tell me how your are going to explain what...
CHEMISTRY
April 17th, 2012
Brainteaser FRIDAY 4/20/12
Tell me how your are going to explain what happened in your experiment and WHY it happened to the rest of the class today during your presentations.
Please give me the title of your experiment too.
Brainteaser MONDAY 4/23/12
According to the KMT, what happens to pressure when you: increase the temperature? Increase volume? Increase the amount of gas molecules? Decrease volume?
Objectives Pressure and Volume: Boyle’s Law
Understand the law that relates the pressure and volume of a gas
To do calculations involving this law
Volume and Temperature: Charles’ Law To learn about absolute zero. To learn about the law relating the volume and temperature
of a sample of gas at constant temperature To do calculations involving this law.
The Combined Gas Law The Ideal Gas Law
To understand the ideal gas law and use it in calculations.
Boyle’s Law: Pressure and Volume
Boyle’s law states that the pressure and volume of a gas at constant temperature are inversely proportional.
Inverse relationship As pressure increases, volume decreasesAs pressure decreases, volume increases
This is Boyle’s LawPV = k
Boyle’s LawWe can use Boyle’s Law to compare:
Volume, at two pressuresPressure, at two volumes
In mathematical terms, this law is expressed as follows:
Temperature and mass (# of particles) are constant
Boyle’s Law: Pressure and Volume
A sample of compressed methane has a volume of 648 mL at a pressure of 503 kPa.To what pressure would the methane have
to be compressed in order to have a volume of 216 mL?
Charles’ Law: Temperature & VolumeCharles’s Law states that, for a given
amount of gas at constant pressure, the volume is directly proportional to the temperature (in kelvins).
Direct RelationshipTemperature increases, volume increasesTemperature decreases, volume decreases
This is Charles’ LawV = kT
Charles’ Law:
At -273 deg C or (O K), the volume of gas extrapolates to zero. This temperature is called the absolute zero.
Absolute zero is the lowest possible theoretical temperature. Theoretically, at absolute zero, the kinetic
energy of particles is zero, so all motion of gas particles at that point ceases.
Charles’ Law: Temperature and Volume
We can use Charles’ Law to compare:Temperature, at two volumesVolume, at two temperatures
In mathematical terms, this law is expressed as follows:
Pressure and mass (# of particles) must be constant
Charles’ Law
A weather balloon contains 5.30 kL of helium gas when the temperature is 12°C. At what temperature will the balloon’s
volume have increased to 6.00 kL?
Brainteaser WED/THURS 25-26
A gas at 330 K occupies a volume of 0.250 L. What volume will be occupied if the temperature drops to 273 K?
Combined Gas Law:Temperature, Volume, and Pressure
Boyle’s Law and Charles’ Law can be combined to look at all 3 variables.
This is the Combined Gas Law:
Temperature must be in Kelvin (K) K = C + 273
Use the combined gas law when pressure, volume or temperature are changing.
Combined Gas Law
A sample of nitrogen monoxide has a volume of 72.6 mL at a temperature of 16°C and a pressure of 104.1 kPa. What volume will the sample occupy
at 24°C and 99.3 kPa?