Here's the pabaon for the 4-days of no classes....
Each problem must be placed in a 1/4 of a long sized
bond paper, then landscape orientation, problems may be printed but the solutions must be handwritten. Use black or blue ink.
60-point project -- 50 points for the problem, ten points for the technical aspect
Have a nice break!!!!!!
PROBLEM SET
A. Heat
Refer to the table below for some constants:
| substance | Melting point °C | Boiling point °C | Hv cal/g | Hf cal/g |
| Ethyl alcohol | -117 | 78.3 | 204 | 24.9 |
| Carbon tetrachloride | -23 | 76.7 | 52.1 | 4.2 |
| Water | 0 | 100 | 540 | 80 |
1. Calculate the amount of heat, in kilojoules, necessary for each of the following changes:
a. to melt 18.5 grams of ice at 0 °C.
b. to liquefy 0.780 mole of ethyl alcohol at its freezing point.
c. to vaporize 8.75 grams of carbon tetrachloride at its boiling point.
d. to convert 0.750 kg of liquid water to steam at 100 °C.
e. to convert 2.45 grams of ice at °C to water at 27.5 °C.
f. to convert 125 grams of water at 85.0 °C to steam at 100 °C.
g. to raise the temperature of 3.25 moles of water from 0 °C to 32.4 °C.
h. to convert 1.35 grams of water at 35 °C to steam at 100 °C.
i. to convert 2.75 kg of ice at 0 °C to steam at 100 °C.
j. to convert 124 grams of ice at 0 °C to water at 25 °C.
Calculate the amount of heat given off when 380.0 grams of steam at 100 °C is converted to ice at 0 °C.
Calculate the number of molecules of water that could be heated from 20 °C to 25 °C by the heat evolved on condensing 85 grams of water vapor to liquid at the boiling point.
Calculate the final temperature of the mixture of 100.0 ml of water at 92.0 °C and 150.0 ml of water at 24 °C.
The specific heat of ethanol (ethyl alcohol) is 2.48 J/g °C for the liquid and 1.60 J/g °C for the vapor. Calculate the heat required to change 5.0 grams of liquid ethanol at 0 °C to 5.0 grams of ethanol vapor at 100 °C.
B. Mole Problems
6. Calculate the mass in grams of 1 mole of each of the following:
a. CaCrO4 c. Na2C2O4
b. CaSO4 d. C6H12O6
7. Calculate the number of moles of the following:
a. 4.80 grams of Aluminum
b. 2.00 x 1024 atoms of Sodium
c. 8.25 grams of NaCl
d. 78.0 liters of CH4 at STP
e. 4.86 x 1026 molecules of Cl2
Calculate the number of molecules in each of the following:
2.50 lb of NH3
0.020 mg of SO2
1.25 gal of water
0.015 mg of carbon dioxide
8.07 mol of CH4
Calculate the mass, in grams, of each of the following:
1.80 mol CO2
2.25 x 1022 molecules of water
0.25 mol of SO3
9.25 liters of NO2 @ STP
2 formula units of Al2(SO4)3
Calculate the amount of heat, in Joules, necessary to carry out each of the following temperature changes:
4.20 x 1024 molecules of water from 0°C to 20°C.
8.20 x 1023 atoms of zinc from 15 °C to 55 °C (cZn = 0.092 cal/g °C)
2.10 x 1025 atoms of tin from 10 °C to 85 °C (cSn = 0.054 cal/g °C)
C. Gas Problems
A sample of gas occupies a volume of 625 mL at 22 °C and 1.12 atm.
Calculate the new pressure, in atmospheres, if the volume is changed to 750. mL and the temperature is changed to 27 °C.
Calculate the volume at STP.
Calculate the new temperature, in Kelvin, if the volume is changed to 535 mL and the pressure is changed to 750 mm Hg.
Calculate the density of each of the following:
carbon dioxide at STP
nitrogen gas at 20 °C and 745 torr
helium gas at 25 °C and 775 mm Hg
NO2 gas at STP
Calculate the molecular weight of each of the following gases:
a gas whose density id 1.75 g/L at STP
a volume of 125 mL of a gas at STP has a mass of 0.420 grams.
a gas whose density is 1.25 g/L at 0.75 atm and 20 °C.
a volume of 245 mL of gas at 27 °C and 740 torr has a mass of 0.825 grams.
Calculate the volume of each of the following:
4.25 grams of O2 gas at STP
0.530 g of Helium at 100 °C and 730 torr
8.25 f of Ne gas at 150 °C and 1.45 atm
Calculate the final temperature in degrees Celsius when 142 mL of gas measured at 480 torr pressure is allowed to expand to a volume of 200. mL at constant temperature.
=end=
due on Sept. 22, 2008
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