Module Five - Gasses Flashcards
What is pressure?
Pressure is the force exerted on a unit area, and is calculated as force/area.
What is the SI unit of force?
The newton, which equals 1 kg m/s^2.
What is the pressure of one newton per square meter?
One pascal, or N/m^2.
What is a kilopascal approximately equal o?
It is roughly equal to the pressure exerted by a 10g mass resting on 1cm^2 area of the earth’s surface.
What is a bar equal to?
100,000 Pa, and approximately the pressure exerted by earth’s atmosphere on the surface.
What is atmosphere?
One atmosphere is 101.325 kPa, which is approximately the pressure of the atmosphere at Earth’s surface.
What is a millimeter of Mercury?
Also known as a torr, 760 mmHg is equal to 1 atm.
What is an ideal gas?
A gas that behaves EXACTLY as described by gas laws. Most gasses behave close to ideally at room temp and atmospheric pressure, however, can deviate quite widely at pressures higher than 1atm or temps higher than boiling point.
What is Boyle’s Law?
A law that states that the volume (V) of an ideal gas is inversely proportional to pressure (P) when temperature (T) and amount (n, moles) are constant.
P1V1 = P2V2 for a gas under two sets of pressure and volume conditions, given unchanging T and n.
What is the kinetic-molecular explanation for Boyle’s Law?
Decrease in gas increases its pressure because there is less room for the gas molecules to move around, thus, there are more collisions with the walls of the container. Each of these collisions means a higher pressure.
What is Charles’s Law?
The volume (V) of an ideal gas is directly proportional to the absolute temperature (T) at a constant pressure (P) and amount (n, moles).
V1/T1 = V2/T2 given unchanging P and n.
What is the kinetic-molecular explanation for Charles’s Law?
Higher temp means faster molecular motion and thus a higher average kinetic energy. This mean the fast-moving molecules strike the wall of the container more often, and each collision exerts a greater force. For this pressure to remain a constant, the volume of the container must expand.
What is Avocado’s Law?
The volume (V) of an ideal gas varies directly with the amount (n, moles) when the temperature (T) and pressure (P) are constant.
V1/n1=V2/n2 given unchanging T and P.
Essentially, at constant temp and pressure, if the gas doubles, so does the volume.
What is the kinetic-molecular explanation for Avogadro’s Law?
Increasing the number of gas molecules increases the number of collisions with the walls in proportion to the amount of molecules. Constant temp implies that the molecules have the same average kinetic energy. More collisions increases the pressure if the volume is held constant, so, to maintain constant P, V must increase.
What is the ideal gas law?
pV=nRT, which summarizes the relationship between these factors. All three other laws can be derived from this. Can be used to calculate one variable if the other three are known, but the gas must be behaving as an ideal gas - the temp must be above it’s boiling and the pressure no more than a few atmospheres.
Under two sets of conditions, this law can be written as P2V2/T2 = P1V1/T1. N is gone because the amount of gas is constant when dealing with the same sample.
