10.1 Properties of Gases Flashcards
Gases have no defininite shape or volume
* will take up the same or volume of whatveer container you stick it in
* This is different than liquid, liquid will take on the shape of the container, but its not going to expand to fill up the container
* So liquid has a definiate volume, but not shape
* Solid has both definite shape and volume
Gases are made up of mostly empty space
* in a liquid/solid this isnt true
* So this makes gases be able to fill spaces they’re in and also makes them very compressible.
* So gases are much more compressible than liquids and solids
Gases mix with other gases in all proportions
* so this is not true of liquids. Think about mixing oil and water, its going to break into their own layers and not mix –> these molecules don’t like eachother very much so they seperate
* However, in gas it doesnt matter how much the molecules dislike eachother, since they’re seperated by empty space mostly they dont ever come that close, but appear to mix –> so they can mix in any proportion
Gases:
P = F/A
* F = Force (Newton)
* A = Area M^2
Si unit for pressure = a pascale (Pa)
* however were going to use atm/tor as well, w/ atm being most common
You stab a watermellon with a marker and a knife
* You stab it with the same amount of force w/ both, however the knife punctures because the area on the tip of the knife is much smaller, and a smaller area = bigger pressure (P = F/A), so essentially you’ve increased the pressure you’ve stabbed it w/.
1atm = pressure of the atmosphere at sea level
* This is just caused by the weight of all the air above you at see level
* thats why if you climb up a tall mountain, you’re not going be under 1atm of pressure - its going to be less - theres less total air pressing down on you.
1atm = 760 mmHg
* 1 atm caused that mecury to push up to 760 mmHg at sea level
1 atm = 760 mmHg = 760 torr = 101,325 Pa
* as long as you’re at the surface of the earth at sea level mmHg = torr - were going to make this assumption in this class
convertin 2atm to torr
1ATM = 760 Tor
convert 2 atm to Pa
