Last quiz...

I don't think that I did so well on the Gas Laws quiz. I know that for the test, I'll need to study the different laws closer, and notice the differences between them. I missed a day, and totally had no clue what STP was, which seems pretty important now.


STP

Air Bag Lab

We had to construct an air bag... one that would save our passenger's life but also not hurt the passenger from being too full of air.
Here's what we decided to do...

1. Find maximum volume of the bag
• Fill bag with water
• pour H2O into a graduated cylinder--- Volume H2O=Volume CO2
2. Calculate to determine amount of NaHCO3 needed
• Volume from step 1, convert to L
• Looking for NaHCO3... n=PV/RT
• solve for moles of CO2
• use stoich to find grams of NaHCO3
• Baking soda=vinegar 1:1 molar ratio
• Use D of vinegar to find volume of vinegar
• x.20 because vinegar is only 5% acetic acid
3. Multiply measurements by .65 to not completely fill up the bag (or explode it)

http://www.chemistry.wustl.edu/~edudev/LabTutorials/Airbags/airbags.html

http://chemistry.about.com/od/chemicalreactions/f/What-Is-The-Equation-For-The-Reaction-Between-Baking-Soda-And-Vinegar.htm

PVNRT

PV=nRT
R=universal gas constant .0821 L atm/ mol K

 

 

 

EX. Calculate the pressure in atm exerted by 1.82 mol of Sulfur Hexaflourine gas in a steel vessel with a volume of 5.43 L at 69.5 degrees C (+273.15)

PV=nRT
P= nRT/V

(1.82 x .0821 x 342.65)/ 5.43
=9.43 atm
http://www.phscale.net/idealgaslaw.htm
http://www.westfield.ma.edu/cmasi/gen_chem1/Gases/ideal%20gas%20law/pvnrt.htm

Measuring Pressure

Common units of pressure:

• Pascal Pa
• Avg Air pressure at sea level 101,325
• Kilopascal kPa
• Avg Air pressure at sea level 101.325
• Atmosphere atm
• 1 exactly
• Millimeters of Mercury mmHg
• 760 exactly
• Inches of Mercury inHg
• 29.92
• Torr torr
• 760 exactly
• Pounds per square inch psi
• 14.7

CONVERT 688 mmHg to atm
688mmHg x (1atm/760mmHg) =  .905 atm

http://www.sengpielaudio.com/ConvPress.htm

Boyle's Law

TELLS THE RELATIONSHIP BETWEEN PRESSURE AND VOLUME IN AN INVERSE RELATIONSHIP

P1V1=P2V2

Ideal gas at low pressure holds strictly to this relationship

http://www.wisegeek.org/what-is-boyles-law.htm

https://www.boundless.com/chemistry/textbooks/boundless-chemistry-textbook/gases-5/gas-laws-51/boyle-s-law-volume-and-pressure-254-8360/