Chemistry: Ch. 11
Which of the following laws states that the volume of the gas and its pressure are inversely proportional?
Boyle's Law
If you double the volume of a constant amount of gas at a constant temperature, what happens to the pressure?
The pressure is one-half the initial pressure.
Pressure units
The simplest unit of pressure is atmosphere (atm) SI unit of pressure is the pascal (Pa) 1 Pa= N/m2 1 atm= 101,325 Pa milliliter of mercury (mm Hg) 1 atm= 760 mm Hg a milliliter of mercury is also called a torr 1 mm Hg= 1 torr inches of mercury (in. Hg) 1 atm= 29.92 in. Hg pounds per square inch (psi) 1 atm= 14.7 psi
Which of the following gases account for 78% of the pressure exerted by dry air?
nitrogen
When a gas is collected over water, is the gas pure?
no
What are the units used to measure pressure?
pascal (Pa) millimeter of mercury (mmHg) atmosphere (atm) torr (torr)
Boyle's Law
pressure and volume
Which of the following air pollutants is one of the main precursors of acid of acid rain?
sulfur dioxide
Compounds with very high vapor pressures must have very minimal intermolecular forces.
true
The measure of the resistance to the flow of a liquid is called
viscosity
Avogadro's law
volume and moles
Charles's law
volume and temperature
Describe the main properties of a gas.
Gases have low densities as compared with solids and liquids. Gases assume the shape and volume of their container. Gases are compressible.
What is the equivalent pressure of 760 torr in units of mm Hg?
760
Explain how drinking from a straw works. What causes the beverage to go up the straw?
A straw works by creating a pressure difference between the inside and outside of the straw. This is done by creating a low pressure on the inside of the straw. The pressure on the outside of the straw is higher than the inside.
Which of following statements are consistent with the Kinetic Molecular Theory? Gases have a low density because there is so much empty space between the particles. Gas particles collide with each other and surfaces without losing any energy. Gases are compressible because the volume taken up by the gas is almost entirely open space. Gases assume the shape and volume of their container because they are in constant, straight-line motion. All of the above statements are consistent with the Kinetic Molecular Theory.
All of the above statements are consistent with the Kinetic Molecular Theory.
Which of the following laws states that the volume of a gas and the amount of a gas in moles are directly proportional?
Avogadro's law
Which of the following laws states that the volume of a gas and its Kelvin temperature are directly proportional?
Charles's law
Pressure is calculated by: P = Area/Force.
False
What are the main assumptions of kinetic molecular theory?
Gas particles are in constant motion and move in straight line. The average kinetic energy (energy of motion) is proportional to the temperature of the gas. Gas particles do not interact with each other (no attraction or repulsion). There is a large distance between gas particles compared to the size of each particle.
What are the main assumptions of kinetic molecular theory?
Gas particles do not interact with each other (no attraction or repulsion). There is a large distance between gas particles compared to the size of each particle. Gas particles are in constant motion and move in straight line. The average kinetic energy (energy of motion) is proportional to the temperature of the gas.
Composition of Dry Air
Nitrogen (N2): 78% Oxygen (O2): 21% Argon (Ar): 0.9% Carbon dioxide (CO2): 0.04%
A gas, behaving ideally, fills a fixed volume container at a pressure P1 and at a temperature T1. The temperature of the container is changed to T2. Using Avogadro's, Charles', or Boyle's law, develop an expression that would solve for the new pressure P2. P1V1 = P2V2 V1/T1 = V2/T2 P1T1 = P2T2 P1/T1 = P2/T
P1/T1 = P2/T
A gas, behaving ideally, has a pressure P1 and at a volume V1. The pressure of the gas is changed to P2. Using Avogadro's, Charles', or Boyle's law, develop an expression that would solve for the new volume V2. P1V1 = P2V2 V1/T1 = V2/T2 P1T1 = P2T2 P1/T1 = P2/T2
P1V1 = P2V2
What is partial pressure?
Partial pressure is the pressure of a single gas in a mixture of two or more gases.
Which symbol used in the ideal gas law is called the ideal gas law constant?
R
All of the following statements are consistent with the kinetic molecular theory of gases EXCEPT:
Strong attractive forces hold the gas molecules together.
Under what conditions is the ideal gas law most accurate? Under what conditions does the ideal gas law break down?
The ideal gas law is most accurate under the conditions of low pressure and high temperature. The ideal gas law breaks down at high pressures and low temperatures.
Explain why hot-air balloons float above the ground.
The gas molecules in a hot air balloon are moving faster and, according to Charles's law, will occupy a larger volume than the same amount of gas at ambient temperature. As the volume occupied by a given amount of gas increases, the density of the gas decreases and the balloon rises due to the buoyancy effect. The air inside the balloon is less dense than air outside the balloon.
Why does the ideal gas law break down at high pressure and low temperature?
The gas particles start interacting, and the distance between gas particles is no longer large.
In the simulation, set the temperature of the sample gas to 304 K. Click on the "Run" button, and observe how the number of moles of the gas varies with an increase in the volume of the gas. Then, click on the "Reset" button, set the temperature of the sample gas to 504 K, and click on the "Run" button again. Observe the graph produced in the simulation, and select the correct options listed below.
The volume of the gas doubles when the number of moles of the gas is doubled at the same temperature. The volume of the sample gas increases linearly with the number of moles.
Which of the following correctly defines the principles of kinetic molecular theory?
There are no attractions between particles.
As you increase temperature, you increase the average energy of the gas particles.
True
Boyle's Law is expressed as:
V is proportional to 1/P
What is Avogadro's law?
V ∝ n
Standard temperature and pressure (STP) are considered to be 273 K and 1.0 atm. Predict which of the following changes will cause the volume of the balloon to increase or decrease assuming that the temperature and the gas filling the balloon remain unchanged.
Volume increases: (1) Balloon filled with helium under water at 1.15 atm is released and floats to the surface, which is at STP. (2) Balloon filled with helium at STP floats into the atmosphere where the pressure is 0.5 atm. Volume decreases: Balloon filled with helium at STP is submerged under water where the pressure is 1.25 atm. Volume unchanged: Balloon filled with helium at STP floats into air where the pressure equals 1 atm.
Determine which of the following relationships are correct according to Boyle's law.
V∝1P and P∝1V
What is Charles's law?
V∝T
Explain why scuba divers should not hold their breath as they ascend to the surface.
When a diver is more than a few meters beneath the surface, the air pressure in the lungs is greater than the air pressure at the water's surface. As the diver ascends to the surface, the volume of air in the lungs would expand as the external pressure decreased.
Evaporation is: an endothermic process. a cooling process for humans when they sweat. increased by increasing temperature. the opposite process to condensation. all of the above
all of the above
Ideal gases ___________.
are compressible
Pressure is the relationship between ___________?
force and area
According to kinetic molecular theory, the particles that compose a gas
have an average kinetic energy proportional to the temperature in kelvins