Exam 3 - Gas Lecture Flashcards
What is a gas?
A substance that has no defined volume or shape
The volume and shape of a gas depend on…
…the size and shape of its container
“Gases are highly compressible”; what does this mean?
When pressure is applied, the volume of a gas changes.
Most of the volume of a gas is actually…
…empty space. Because of this, each gas molecule behaves as if no other molecules are present.
Generally, gases are small molecules comprised of…
…nonmetals
What is pressure?
The force exerted on a given unit area.
What is the SI unit for pressure?
Newtons per square meter
What is the most common English unit for pressure?
Pounds per square inch, or psi.
What are the four variables used to describe a gas?
Pressure, amount, temperature, and volume. They are all interrelated.
The mass of a 1 square meter cross-sectional volume of atmosphere has a mass of 10,000kg, which corresponds to…
100,000N
Total pressure is also called…
…absolute pressure
Difference of height is sometimes called…
…Pressure gage
What is a barometer?
It is a device used to measure atmospheric pressure. The gases in the atmosphere exert pressure on the Hg, causing it to rise in the tube. The pressure is reported as the distanced the Hg moves up the tube. Under typical atmospheric conditions, the distance is approximately 760mm, or 30 inches.
What is a manometer?
A device used to measure the pressure of a gas sample. It is similar to a barometer, but instead of one end being under a pol of Hg, it is attached to a gas sample.
What are the relationship between pressure, temperature, amount, and volume?
Gas Laws
What are the three Gas Laws?
Boyle’s law, Charle’s law, and Avogadro’s law.
Boyle’s law…
…relates the volume of a gas to its pressure. At a constant temperature and with a fixed quantity of gas, pressure and volume are inversely related. (If we decrease the volume of a gas, its pressure increases)
Charle’s law…
…It relates the volume of a gas to its temperature. The law states that at a constant pressure and with a fixed quantity of gas, temperature and volume are directly related.
When dealing with gases, temperature needs to be in…
…Kelvin
What is the Charle’s Law formula?
V1/T1 = V2/T2 (KELVIN)
What is the Boyle’s Law formula?
P1V1=P2V2
What is the Avogadro’s Law formula?
V1/n1 = V2/n2
What is the Ideal Gas Law?
Pv=nRT (R is 0.08206)
What is the combination between Charle’s and Boyle’s formulas that relates pressure, temperature, and volume of a sample of gas?
P1V1/T1=P2V2/T2
What happens to the molecules of gas when they get bigger?
They start to deviate from standard behavior
What type of mixture is formed when gases are mixed with other gases?
Homogeneous, ALWAYS!
What is the law of partial pressures?
It is the pressure exerted by an individual component of a mixture, which is called partial pressure
The overall pressure of a gas depends on:
The number of moles of gas, temperature and volume
