# General Chemistry: Energy, Volume, Mass, Molarity, and Moles

Benzene is an organic solvent with the formula C6H6. It boils at 80.1 degrees celcius and melts at 5.5 degrees Celsius. Benzene's density is 0.88gm/ml; its heat of vaporization is 30.0 Kjoules per mole; its heat of fusion is 7500 Joules per mole; and its heat capicity is 120 Joules per mole degree C for liquid benzene, 75 Joules per mole degree C for solid benzene, and 90 Joules per mole-degree C for gaseous benzene. Calculate the following:

a) the energy removed to cool 39 grams of benzene from150 degrees celcius to 100 degrees Celsius.

b) the energy required to heat 3.9 grams of benzene from 15 degrees celcius to 60 degrees Celsius.

c) the energy removed to cool 390 grams of benzene from -70 deg celcius to -90 deg Celsius

d) the volume occupied by 1 mole of liquid benzene and the volume occupied by 1 mole of benzene as a vapor at STP (assume an ideal gas)

2. In the reaction barium chloride plus potassium chromate yields potassium chloride and barium chromate. 10.0 grams of barium chloride is mixed with 100 grams of water to make a barium chloride solution, which has a volume of exactly 100 ml. It is titrated with a solution of 100 grams of potassium chromate dissolved in sufficient water to make 500 ml of solution. Calculate the following:

a) the mass percent of the barium chloride

b) the molarity of the potassium chromate solution

c) the volume of potassium chromate solution required to react with all the barium chloride solution.

d) the mass off potassium chromate required to react with ten times the volume of the barium chloride solution

e) if 10.0 grams of barium chloride were dissolved in sufficient water to make 1 liter, how many grams of potassium chromate would be required to react completly with all the barium chloride?

3. Aluminum metal melts at 660 deg celcius and boils at 2450 degrees celcius. its density is 2.70 grams/ml. Calculate the following:

a) the volume occupied by 15 grams of aluminum vapor at its boiling point and under a pressure of 380 torr ( assume an ideal gas)

b) the volume occupied by 100 grams of the metal at 25 degrees Celsius.

c) if the specific heat capacity of aluminum metal is 0.89 joules per gram-degree C, how many Joules of energy are required to heat 10 moles of aluminum from 100 deg celcius to 600 deg Celsius?

d) if the mass in part 1 of this problem is subjected to 100 atmospheres pressure at the boiling point, what would the volume be (assume an ideal gas)

e) if the mass in part 1 was dissolved in an excess of aqueous HCL, what volume of hydrogen gas would be released at STP?

#### Solution Summary

Calculations and answers are provided in four attached JPG documents. Work is completed by hand and scanned.