Due Wednesday 11:59 PM February 22, 2000 Quiz 7: Solids, Liquids & Gases: States of Matter

Short essay questions

1.	10 points
-----	A barometer is shown in the illustration. What is the approximate indicated air pressure in mm Hg? What is this pressure in atmospheres? What is this pressure in PSI, pounds per square inch? Would this be classed as LOW pressure? What would happen to the mercury level if the density of the atmosphere above decreased? Justify your answer.

2.	10 points
-----	A balloon initially had a volume of 3000 liters at 20oCelsius and 1.0 atmospheres. Show set ups for calculations. a. How many moles of gas are in the balloon? b. What is the volume of the balloon at 30o Celsius and a pressure of 0.96 atm?

 

3.	6 points
-----	Does a compound like propane, CH3CH2CH3, show hydrogen bonding? Tell what kind of forces exist in propane. Justify your answer.

4.	10 points
-----	Which of the four has the strongest intermolecular forces? Justify your answer. If possible tell what the approximate boiling point for each liquid would be if the opposing pressure was lowered to 400 torr (400 mm Hg)? Compound diethyl ether ethyl alcohol water Boiling point at 400 torr ------------------------------ ------------------------------ ------------------------------

5.

8 points

Which of the following gases has the smallest density at STP? What generalization can be made about the relation of gas density to molar mass? Calculate the densities to support your answer. Explain your answer. Show a sample calculation. Compound N2 CO2 Density at STP ---------------------------------- ---------------------------------- Molar mass ---------------------------------- ----------------------------------

	True false 2 point each
1.	A simple cubic unit cell has one "atom" inside the cell.
2.	The body centered cubic unit cell contains 2 atoms inside the unit cell.
3.	Hydrogen bonding can exist when molecules have any of the following bonding combinations. H-F, H-O, H-N.