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Rault's Law, reaction enthalpy


Ice-cream

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can i have some confirming plz?

 

1. The vapour pressure of pure water at 25 degrees c is 23.8 mmHg. Determine the vapour pressure of water at 25 degrees C above a solution containing 33.2 g of urea (a nonvolatile, nonelectrolyte, MW = 60g/mol) dissolved in 75 g of water.

 

(i found no. of moles of urea = 0.5533 and no. of moles of water = 4.1667. since P(solution) = x(solvent) x Pure pressure (solvent), P(solution) = 21.01 mmHg.) does anyone agree with my answer?)

 

2. Calculate the reaction enthalpy in kJ for the formation of anhydrous aluminium chloride

 

2Al(s) + 3Cl2(g) --> 2AlCl3(s)

 

from the data:

2Al(s) + 6HCl(aq) --> AlCl3(aq) + 3H2(g) delta H = -1049 kJ

HCl(g) --> HCl (aq) delta H = -73.5 kJ

H2(g) + Cl2(g) --> 2HCl(g) delta H = -185 kJ

AlCl3(s) --> AlCl3(aq) delta H = -323 KJ

 

(the answer i got was -1399kJ...does anyone agree?)

 

thanx

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