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Sample Exam 4 CHM2045



Numeric Response
 

 1. 

A 11.8 L gas cylinder contains three gases. 7.8 moles of Ar, 0.64 moles of Ne, and an unknown quantity of a contaminant. The pressure of gas in the cylinder is 21.5 atm at room temp (25.0 ºC). How many moles of the contaminant are present? What is the partial pressure of the contaminant?

 

 2. 

You are on a deserted island and need a barometer to predict tropical storms. The fluids on the island are Corn Oil  d=0.9222g/mL, gasoline d=0.69g/mL and whale oil d=0.925g/mL. Which should you use, and how long will the tube need to be to read atmospheric pressure in mm? ( It may be useful to know that dHg is 13.69 g/mL) . Explain.

 

Short Answer
 

 3. 

A person applying cologne in the back of a lecture hall is detected almost immediately by the instructor in the front of the class. Explain, in terms of Kinetic Molecular Theory.
 

 4. 

van der Waal's equation accounts for what deviations from ideal behavior?
 

 5. 

Water evaporates from a glass at normal room temperature. Why?
 

 6. 

Arrange the following in order of increasing melting points. Explain your reasoning.

samex4_files/i0080000.jpg
 

 7. 

A can of beanie weenies is placed, unopened, on an open fire ( Temp roughly 2700 ºC). At room temp (25.00ºC) , 6.24 ml of air are present. The pressure is the unopened can was 740 torr. Assuming that the can doesn't explode, what is the pressure of gas in the can while it is in the fire?
 

Essay
 

 8. 

4. Consider the phase diagram below.
a)What phase(s) are/is present at 25 atm and 70 C?
b) Label pertinent features
samex4_files/i0110000.jpg
 

 9. 

Once upon a time, a young marshmallow peep was sent into outer space.  His space suit got a tear in it.  What was his ultimate fate?
 

 10. 

A bag of potato chips is purchased in Denver and placed in the trunk of a car.  As the car travelled back to Jacksonville, what happened to its appearance and why?
 

 11. 

Two gases,  Moxium and Bellium are released in a tube.  It is observed that Moxium travels at twice the speed as Bellium.  What can be concluded about the two particles?
 



 
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