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Warm Up 4/9 Write the formula of magnesium chloride. Hint: Mg has a charge of +2. Cl has a charge of -1. Gas Laws. Lesson : Kinetic Molecular Theory. Solids/Liquids/Gases. Describe the molecules in the following images. - PowerPoint PPT Presentation
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Warm Up 4/9
Write the formula of magnesium chloride.
Hint: Mg has a charge of +2. Cl has a charge of -1.
Gas Laws
Lesson: Kinetic Molecular
Theory
Solids/Liquids/GasesDescribe the molecules in the
following images.
Kinetic Molecular TheoryA model that assumes that an ideal
gas is composed of tiny particles (molecules) in constant motion.
Ideal Gas- an imaginary gas that
perfectly fits all of the KMT.
5 Parts of KMT:
1. Matter is composed of very small
particles called molecules.
2. Molecules are in constant motion.
The collisions with the walls of the
container cause pressure.
Continued3. When the molecules collide with
each other or the walls of a
container, there is no loss of energy
(elastic collision).
4. There are no forces of attraction
or repulsion between gas particles,
but they collide and change
direction.
5. The average kinetic energy of gas
particles depends on the temperature
of the gas.
Temperature- measure of the
average kinetic energy of
particles.
Pressure Units Standard atmosphere (atm)
1 atm= 760 mm Hg = 760 torr
Pascal- SI unit for measuring
pressure:
1 atm= 101300 Pa = 101.3 Kpa
Draw a picture for each of
the parts of the KMT.
Warm Up
If an atom has a charge of -2, has it been oxidized or
reduced?
Lesson: Gas Laws
(Part 1)
Gas Laws
Gas laws express the behaviors of gases as
mathematical relationships.
Boyle's Law-Pressure and volume
-States that the pressure and volume of
a gas are inversely proportional to
each other at constant temperature.
Boyle's Law
Formula:
P1*V1 = P2*V2
P1= initial Pressure P2= final
pressure
V1= initial volume V2= final volume
A gas has a volume of 1.25 L and a pressure of 755 torr. What will the new volume be if the pressure is increased to 2667.6 torr?
Boyle’s Law Example
Charles' Law-Volume and temperature
-The volume of a gas is directly
proportional to the temperature
at constant pressure.
Charles' Law
Formula:
V1= initial volume V2= final volume
T1= initial temperature T2= final
temperature
**Temperature must be in Kelvin!
V1 V
2
T1 T
2
=
If a gas has a volume of 247 mL at 25.0°C, what will the new volume be if the temperature is increased to 308°C?
Charles’s Law Example 1
If a gas has a volume of 247 mL at 25.0°C, what will the new temperature be if the volume is increased to 255 mL?
Charles’s Law Example 2
Ideal Gas Law
P= pressure (in atm)
V = volume (in Liters)
n = number of moles
R = universal gas constant
T = temperature (Kelvin)
-
Formula: PV = nRT
Universal Gas Constant (R)
-value can vary depending on
pressure units being used.
R= 0.0821 L·atm mol·K
Example #1 (Ideal Gas Law)What is the pressure of 5 moles
of a gas at 30°C in a 2 liter container?P x 2 L = 5 mols x 0.0821 x 303 K
2 L 2 L
P = 60 atm
Example #2 (Ideal Gas Law)A 250 mL of a gas exerts a pressure
of 760 torr at 10°C. How many moles of gas are present?1 atm x 0.250 L = n x 0.0821 x 283 K
0.0821 x 283 K
n = 0.0108 mol
(0.0821 x 283 K)
7) If I have 4 moles of a gas at a pressure of 5.6 atm and a volume of 12 liters, what is the temperature?
8) If I have an unknown quantity of a gas at a pressure of 1.2 atm, a volume of 31 liters and a temperature of 87°C, how many moles of gas do I have?
9) If I put 3 moles of gas in a container with a volume of 60 liters and at a temperature of 400 K, what is the pressure inside the container.
10) If I have 7.7 moles of a gas at a pressure of 0.09 atm and a temperature of 56°C, what is the volume of gas?
Get your notebooks!
You will find your score near the last page.
AgNO3 (aq) + KCl (aq) → AgCl (s) + KNO3 (aq)
What type of reaction?
What type of reaction?
2NaOH + H2SO4 → 2H2O + Na2SO4
2Mg + O2 → 2MgO
What type of reaction?
Write the ionic formula of the following ions:
Na O
What is the following temperature in Kelvin?
20°C
How many torr are in 2 atm?
What is the ideal gas formula?
What is instrument is used to measure atmospheric gas
pressure?
Lesson: Gas Laws
(Part 2)
Dalton's Law of Partial Pressures-states that the pressure of a gas mixture is
the sum of the partial pressures of the individual components of the gas mixture.
Formula: Ptotal
= P1+P
2+P
3+...
Example (Partial Pressure)A mixture of oxygen, hydrogen and nitrogen
gases exerts a total pressure of 278 kPa. If the partial pressures of the oxygen and the hydrogen are 112 kPa and 101 kPa respectively, what would be the partial pressure exerted by the nitrogen?
Avogadro’s Law-Volume and number of moles
-States that the volume and # of moles
of a gas are directly proportional to
each other at constant temperature
and pressure.
Avogadro’s Law
Also means: Equal volumes of 2 gases at the same temperature and pressure have equal numbers of moles.
STP = Standard Temperature and Pressure (0°C, 1 atm)
1 mole of gas = 22.4 L at STP
Avogadro‘s Law
Formula:
V1= initial volume V2= final volume
n1= initial # of moles n2= final # of moles
Example
Mass: 0.214 mol Mass: 0.375Volume: 652 mL Volume: ?
ExampleCalculate the volume that .881 mol
of gas at standard temperature and pressure will occupy.
1. If a mixture of oxygen gas and water vapor have a total pressure of 754 torr, and the water vapor has a partial pressure of 21 torr, what is the partial pressure of the oxygen?
2.Mass: 46.2 g O Mass: 5.00 g OVolume: 100. L Volume: ?
Hint: the mass needs to be in moles, so look up the molar mass and use a molar mass conversion fact to calculate the # of moles.
Left Side Practice
Behavior of Gases
1. Gases can expand
2. Gases can be
compressed
** Expansion and compression are affected by temperature and pressure.
Temperature Measure of the average kinetic energy
Kinetic Energy = 1/2 mv2
Units: Fahrenheit (°F), Celsius (°C), and Kelvin (K)
Kelvin (K): directly relates temperature to kinetic energy
Absolute Zero: 0K, temperature where motion stops
Converting temperature
Celsius to Kelvin
TKelvin = TCelsius + 273
Kelvin to Celsius
TCelsius = TKelvin -273
PracticeConvert the following temperatures to Kelvin or Celsius.
1. 15°C
2. 100 K
3. 125°C
4. 0 K
5. 722 K
6. –100°C
Pressure
Pressure- force per unit of area
Gas pressure- the force exerted upon a container by a gas; caused by gas particles striking the sides of the container.
Standard Temperature and Pressure
*Standard set of experimental conditions used to make comparison of data easier.
At STP: T= 0°C and P= 1 atmosphere
