Saturday, May 22, 2010

Please help! Aluminum metal melts at 660 degrees C and boils at 2450 degrees C. Its density is 2.70 grams/cc.?

Calculate the following:


A. Assuming an ideal gas, the volume occupied by 20.0 kilograms of aluminum vapor at its boiling point and under a pressure of 2280 torr.


B. The volume occupied by 1000. kilograms of the metal at 25 degrees C.


C. If the specific heat capacity of aluminum metal is 0.89 Joules per gram-degree C, how many calories of the energy are required to heat 10 kilomoles of aluminum from 250 degrees C to 500 degrees C


D. If 13.5 grams of aluminum were dissolved in an excess of concentrated HCI, what volume of hydrogen gas would be released at STP? You may assume that the ideal gas law holds and that the vapor pressure of water is negligible compared to the pressure of the released hydrogen.

Please help! Aluminum metal melts at 660 degrees C and boils at 2450 degrees C. Its density is 2.70 grams/cc.?
A. Divide 20000 g of Al by its g-atomic weight, call result M g-atoms. Using PV = MRT, compute V for P=2280 torr and 2450+273 degK and the R in units which include torr.


B. Divide 1000 kg by 2.70 kg/L, result in in L


C. Multiply 10^4 g-atoms of Al by its g-atomic weight, call result G grams.


Then Energy = G * 0.89 * [500-250] in joules.


convert to calories.


D. Divide 13.5 g by g-atomic weight of Al, call result A g-atoms. From rxn,


2 Al+ 6 HCl -%26gt; 3 H2 + 2AlCl3


3 moles of H2 are formed from 2 g-atoms of Al. So, find moles of H2 by finding (3/2)*A.


Multiply (3/2)*A by 22.4 L/mole to get gas volume


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