Posted by Anonymous on .
Mass of flask, boiling chips, foil cap and unknown after cooling reaction 83.350g
2.Mass of flask, boiling chips,and foil cap. 82.657
3. water bath temperature C is 95.0 C
4. Barometric pressure inches of Hg 30.09
5. Accepted molar mass of unknown is 86.2g/moles
6. Volume of flask is 270 mls
1. Calculate mass of unknown.
2. Express water bath temperature in Kelvin
3. Express barometric pressure in standard atmospheric pressure
4. Express volume of flask in cm3
5. Calculate density of vaporized unknown.
Answers so far
1. 0.697 g
2. 368.15 K
4. 270 cm3
5. How can I determine the vaporized unknown?
I believe 1 is not quite right. Probably just a typo but 83.350-82.657 = ??
3. 30.09 inches Hg x 25.4 mm/inch = 764.286 mm Hg which is ok. However, the question asks for atmospheres, not mm Hg so divide by 760.
5. density. I am unsure exactly what you are doing.
P*molar mass = density*RT so you can calculate density BUT that doesn't use any of your data other than the molar mass. (It doesn't use the 0.693 g) so I don't think that is the approach to take.
However, you can calculate moles from
PV = nRT. From moles = grams/molar mass you can calculate experimental molar mass (which isn't 86.2), then
density = molar mass/22.4 g/mol which will give you the experimental density of the vapor.
A cubic piece of metal measures 6.50 on each edge. If the metal is nickel, whose density is 8.90 , what is the mass of the cube?