Flashcards in Chemistry Set 3 Deck (41)
What are gas laws?
Gas laws are theories about what makes gasses tick.
What are the four gas laws?
Boyle's law, Charles's Law, Gay-Lussac's Law, Avogadro's Law
Who was Robert Boyle?
Robert Boyle was an English chemist who in 1662 found that if you push on gas its volume will decrease (it will get smaller)
Explain what Boyle found?
Boyle discovered that if you increase the pressure on gas two times, it will reduce its volume by ½. And the opposite is also true, if you reduce the pressure on gas by ½ then the volume will double. There is a ratio to predict the size change in the gas.
What type of relationship is Boyle's law?
Boyle's law is an inverse relationship. When one goes up, the other goes down.
How was Boyle's law used to help female flight attendants?
British Airways flight attendants had a skirt problem. It fit on take off but was too tight in the air. They realized that as cabin pressure in the cabin increases, pressure in the stomach decreases making their tummies too big for their skirt. Now they wear adjustable clothes.
How does a syringe use Boyle's law?
When the plunger of a syringe is pulled out, the pressure inside the syringe decreases as its volume increases. Fluids flow from high pressure to low pressure so flow into the syringe.
How do your lungs use Boyle's law?
When you inhale your diaphragm lowers which increases the volume in your lungs, lowering the air pressure in your lungs, so your body draws in air. When your diaphragm pushes upwards, the volume is reduced and air is pushed out.
How do weather balloons need to be adjusted for Boyle's law?
They are only partly filled with gas at ground level, as the gas will expand as it gets higher in the air as the air pressure outside the balloon will be less that the pressure inside the balloon so the gas will expand.
What did Jacques Charles find out?
Charles discovered in the 1870s that heating gas will make it expand.
How does heating or cooling affect molecules?
Heating speeds up molecules and cooling slows molecules down.
What is Charles's law?
Charles's law is that if you heat up a gas it will expand; if you cool gas it will shrink
How is Charles's law used in hot air balloons?
They heat the air, the air expands inside the balloon, its density decreases, so when the density of the air inside the balloon decreases the balloon rises
How does a turkey thermometer use Charles's law?
When the air inside the turkey thermometer expands, the top pops up, and it is timed so that you know the inside of the turkey is hot enough.
What did Gay-Lussac find out?
In 1802 Gay-Lussac found that if you keep the volume of a gas constant, like in a closed container, and yo apply head the pressure of the gas will increase.
Why does the pressure of gas increase if it is heated in a closed container? (a fixed volume container)
The pressure builds because the gas molecules have nowhere to go except get squished up against each other which they don't want to do, they want to expand
What do molecules gain from heat?
Molecules, when heated, gain energy, which becomes kinetic energy which is moving energy, so they hit the walls of the container with more pressure when they are heated.
How does a pressure cooker use Gay-Lussac's law?
The food and water is in a tightly sealed pot, the heat is increased, the temperature goes above boiling but nothing can escape as steam, so the food cooks much faster and tough meat is tender
Why does a tire's air pressure go up after you are driving for a while?
The friction of the tire on the road heats the tire, which heats the air inside the tire, so the pressure goes up because the air has no where to go in the sealed tire.
What did Amadeo Avogadro find out?
Avogadro, in 1811, found out that a volume of any gas has a relationship (is proportional) to the number of molecules of the gas.
How are molecules measured?
Molecules are measured in Moles mol
How can you compare gasses with Avogadro's law?
the temperature, pressure and volume of the container must be identical, the measurement of mol must be the same, but then you can compare the weight of the gas in grams.
If temperature, volume, mol, and pressure are all the same, what is the only thing that changes when you are comparing gasses?
The overall weight (mass) measured in grams will change.
one mole of any matter is equal to how many molecules?
6.02 x 10 to 23 this is Avogadro's number
What frequent activity is an example of Avogadro's law?
Blowing up a balloon adds molecules to the inside of the balloon.
What is the Ideal Gas Law?
The ideal gas law combines all four discoveries about gas.
What is the equation for the ideal gas law?
What is p in pV=nRT
What is V in pV=nRT