According to the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE), the minimum vacuum level in a system should be __________ microns. 

A. 1,000
B. 2,000
C. 3,000
D. 5,000


Answer: A

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This problem concerns a compound that can be modeled, in both the liquid and the vapor phase, by the following equation of state: Z=1+(aT^0.5)/?V+b/?V^2 Where a= -0.09 LK-0.5mol-1 and b = 0.5 L2mol-2. The table below gives the three possible molar volumes resulting from this equation at two different pressures and a temperature of 300K.


In the solid phase this compound has a molar volume of 0.35 L/mol and a fugacity f =2 atm at P = 1 atm and T = 300 K.

A) Derive algebraic expressions for the liquid and vapor fugacities of this compound (f^Land f^V) as a function of temperature, pressure, volume, and/or known constants.
B) Is this compound a solid, liquid or vapor at P=1 atm and T=300 K? Give calculations to demonstrate your answer.
C) Is this compound a solid, liquid or vapor at P=4 atm and T=300 K? Give calculations to demonstrate your answer.

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Soils that have a large percentage of clay can cause problems for plants

Indicate whether the statement is true or false

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Geese pair up on their _____ to begin reproduction

a. flight south b. summer areas c. resting areas d. wintering grounds

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The amount of extra water needed to over-irrigate a soil enough to leach salts out of root zones is

called the leaching fraction.

Indicate whether the statement is true or false.

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