crhs academic chemistry unit 11 gas laws notes academic chemistry unit 11 gas laws notes quiz date...
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Name _______________________ Period ______
CRHS Academic Chemistry
Unit 11 Gas Laws
Notes
Quiz Date ______ Exam Date _______ Lab Dates ______ _______
Notes, Homework, Exam Reviews and Their KEYS located on CRHS Academic Chemistry Website: https://cincochem.pbworks.com
Page 2 of 12 Unit 10 Notes
11.1 GAS PROPERTIES
In Chemistry, we will consider ALL GASES to be ____________________.
Q: What is an ideal gas? An ideal gas is any gas that meets the 5 basic assumptions of ___________________
______________________ theory stating how the particles of any _______________ move.
The 5 Basic Assumptions:
1. Gas particles do not ___________________ or ______________ each other.
2. Gas particles are much ____________________ than the distances between them.
a. almost all the volume is _____________ ____________
b. explains high compressibility
3. Gas particles are in _______________ _____________ motion.
a. particles move in _________________ ____________ until collision
b. explains why gases __________________ any container
4. No __________________energy is lost when gas particles collide with each other or the walls of their container.
5. All gases have the _______________________ average kinetic energy at a given ________________________.
Gases and Increasing Temperature
When gases are heated, kinetic energy ___________________..
When a gas has _______________ kinetic energy, its particles push harder on the container or surroundings.
If the container can expand, the gas _______________will increase.
o A rubber balloon
If the container cannot expand, gas _______________ will increase.
o A rigid container, like a glass jar.
Avogadro’s Law – two different gases of equal volume at the __________________ pressure and temperature have
equal numbers of _______________________, _________________ and _____________ , regardless of the identity of
either gas. So, gas particles, when under the same sets of physical conditions, will all behave the same way.
Unit 10 Notes Page 3 of 12
We learned in the stoichiometry unit that 1 mole of ANY gas at standard temperature and pressure contains
________L of gas.
Dalton’s Law of Partial Pressures
In a ___________________ of gases, the _____________pressure exerted by the mixture of gases is equal to the
____________of the partial pressure of each gas.
Example – Air contains N2, O2, H2O, Ar, CO2, the sum of which makes up the air pressure around us at any time.
At sea level, the air pressure is 101.3 kPA, but air is not a pure gas, it is a mixture of the above gases along with a few
other trace gases.
N2 + O2 + H2O + Ar + CO2 = Air 78.1 kPa + 20.9kPa + 1.28kPa + 0.97kPa + 0.05kPa = 101.3kPa
Ptotal = PGas 1 + PGas 2 + PGas3 …
Page 4 of 12 Unit 10 Notes
11.2 IDEAL GAS LAW
1. Pressure (____)
created by the molecules of gas _____________________ with the walls of the container
Standard International Unit, or ______ unit, is the _________________________________, kPa.
Standard pressure = ______ kilopascals
_________kilopascals = _____ atmosphere = ________ mm Hg
Practice: Convert 1.4 atmospheres of pressure to kPa.
2. Temperature (____)
a measure of the ____________________energy of gas particles
temperature is _______________________ proportional to kinetic energy
SI unit is _____________________ (K) –NO degree symbol!
ALL calculations in this unit are in KELVIN
To convert from Celsius,
Standard temperature = ________K = _______C
0 K is called “___________________ zero”, the temperature at which the motion of particles theoretically
_______________.
Practice: Convert 33°Celsius to Kelvin.
3. Volume (_____)
the 3-D space enclosed by the a container’s ______________
SI unit is ______________(L)
At standard temperature and pressure (STP), there are __________________ of a gas per one mole of that gas.
K =
Unit 10 Notes Page 5 of 12
4. Number of Moles (_____)
_____________________of gas present, in _______________
if amount is given in grams, we will ______________ to moles
STP = standard temperature and pressure
o Temperature: 0°C = 273K
o Pressure: 101.3kPa = 1 atm = 760 mmHg
We can use the ________________________ that describe a gas to find unknown properties of an _____________ gas.
Remember…
Pressure (P) Temperature (T) Volume (V) Moles (n) All calculations are done using KELVIN temperatures!
Q: What is R? – R is the ideal gas _______________________________. There are ideal gas constants for pressure in
kPa, atm, and mmHg. .
Example 1 – When the temperature of a hollow sphere with 685 L (volume) of helium gas is held at 621 K
(temperature), the pressure of the gas is 1.89 x 103 kPa. How many moles of helium does the sphere contain?
pressure in kilopascals
𝑹 =8.31 L ∙ 𝐤𝐏𝐀
mol ∙ K
pressure in atmospheres
𝑹 =0.0821 L ∙ 𝐚𝐭𝐦
mol ∙ K
pressure in mm Mercury
𝑹 =62.4 L ∙ 𝐦𝐦𝐇𝐠
mol ∙ K
Page 6 of 12 Unit 10 Notes
Example 2 – What pressure in kPa will be exerted by 0.450 mole of a gas at 25 C if it is held in a 0.650L container?
Example 3 – What volume will 2.50 mol of nitrogen gas occupy at STP (0°C and 1 atm of pressure)?
Example 4 – What volume will 12.0 grams of oxygen gas occupy at 25 C and a pressure of 0.520 atm?
Hint 1: HOFBrINCl Hint 2: convert grams to moles
Unit 10 Notes Page 7 of 12
11.3 COMBINED GAS LAWS AND BOYLES LAW Combined Gas Law - states the relationship among pressure, volume, and temperature of a fixed amount of a gas under
_________ sets of conditions.
We are given 5 of 6 values, so we can calculate the missing value.
We MUST use Kelvin for temperature
Example 1 – A gas at 155 kPa and 25.0C occupies a container with an initial volume of 1.00 L. By changing the volume,
the pressure of the gas increases to 605 kPa as the temperature is raised to 125C . What is the new volume?
Practice 1 – A 5.00 L air sample at a temperature of –50.0C has a pressure of 1.056 atm. What will be the new pressure
if the temperature is raised to 102C and the volume expands to 7.00 L?
Practice 2 – A 6.000 L sample of air has a pressure of 757.6 kPa. What volume will it occupy at 187.5 kPa if the
temperature is held constant at 273 K?
Page 8 of 12 Unit 10 Notes
Q: What is Boyle’s Law?
Boyle’s Law - _________________________________ is held constant.
As pressure ____________________________, volume ____________________________.
As pressure ___________________________,
volume __________________________.
______________________ relationship
Record your observations from the class demonstration below.
__________________________________________________________________________________________________
____________________
Example 1 - A high altitude balloon contains 30 L of helium gas at 103 kPa. What is the volume when the balloon rises to
an altitude where the pressure is only 25 kPa? (Assume that temperature remains constant.)
Practice 1 - A tank of nitrogen has a volume of 14.0 L and a pressure of 1.0 atm. Find the volume of the nitrogen when
the pressure is increased to 2.1 atm while the temperature is held constant.
Practice 2 - The volume of the lungs is measured by the volume of air inhaled or exhaled. If the volume of the lungs is
2.40 L during exhalation and the pressure is 101.70 KPa, and the pressure during inhalation is 101.01 kPa, what is the
volume of the lungs during inhalation? Temperature is constant.
Unit 10 Notes Page 9 of 12
11.4 CHARLES AND GAY LUSSAC LAW
Q: What is Charles’s Law?
Charles’s Law - _______________________________ is held constant.
As temperature _______________________, volume __________________________.
As temperature _______________________, volume __________________________.
______________________ relationship
Record your observations from the class demonstration below.
__________________________________________________________________________________________________
____________________
Example 1 - A balloon inflated in a room at 24 °C has a volume of 4.0 L. The balloon is then heated to a temperature of
58 °C. What is the new volume if the pressure is held constant?
Practice 1 - If 15.0 liters of neon gas at 25 °C is allowed to expand to 45.0 liters, what must the new temperature be to
maintain constant pressure?
Practice 2 – A 600L sample of oxygen gas is stored in a flexible container at 15 °C. It is suddenly heated to 42°C. What
will the new volume be, assuming pressure is unchanged?
Charles’s Law
Page 10 of 12 Unit 10 Notes
Q: What is Gay-Lussac’s Law?
Gay-Lussac’s Law - ______________________________is held constant.
As temperature ___________________________, pressure ______________________.
As temperature ___________________________, pressure ______________________.
_____________________ relationship
Record your observations from the class demonstration below.
__________________________________________________________________________________________________
____________________
Example 1 - The gas left in a used aerosol can is at a pressure of 103 kPa at 25°C. If this can is thrown into a fire, what is
the pressure of the gas when its temperature reaches 928 °C?
Practice 1 - If a gas in a closed container is pressurized from 15.0 atm to 16.0 atm and its original temperature was 25 °C,
what would the final temperature of the gas be?
Practice 2 –A solid, sealed steel container full of carbon dioxide gas is being heated from a starting temperature of 22°C.
The final temperature is 635°C and the final pressure is 431 kPa. What was the original pressure of gas inside the
container?
Gay-Lussac’s Law
Unit 10 Notes Page 11 of 12
Dalton’s Law
Ideal Gas Law
Combined Gas Law
Boyle’s Law
Charles’s Law
Gay-Lussac’s Law
STP Temperature: 273K = 0°C Pressure: 101.3 kPa = 1.0 atm = 760 mmHg K = °C + 273
𝑃1𝑉1 = 𝑃2𝑉2
𝑃1𝑉1
𝑇1=
𝑃2𝑉2
𝑇2
𝑃𝑉 = 𝑛𝑅𝑇
𝑉1
𝑇1=
𝑉2
𝑇2
𝑃1
𝑇1=
𝑃2
𝑇2
𝑃𝑇𝑜𝑡𝑎𝑙 = 𝑃1 + 𝑃2 + 𝑃3 …
Page 12 of 12 Unit 10 Notes