Phosphorous pentachloride (PCl5) is used in the industrial preparation of many organic phosphorous compounds. Preparation of phosphorous pentachloride from PCl3 and Cl2 is given by the reaction :
(Eqn. 1) PCl3(l) + Cl2(g) PCl5(s)
Use the two equations below to calculate Hrxn of equation (1)
(Eqn. 2) P4(s) + 6 Cl2(g) 4PCl3(l)
H = -1280kJ
(Eqn. 3) P4(s) + 10Cl2(g) 4PCl5(s)
H = -1774 kJ
Hrxn = kJ
2007-11-19 10:14:48 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
-123.4 kJ
Equ 2 should be reversed which means that H should be positive now. Nothing is done to equ 3. This gives an H of -494kJ. But, the equation is 4 Cl2 + 4PCl3 --> 4 PCl5 so you need to divide the 494 by 4 which gives -123.4 kJ
2007-11-19 10:22:33 · answer #1 · answered by Anonymous · 0⤊ 0⤋
To use Hess Law, the equations from which you wish to deduce a third reaction must balance.
So reverse equation 1
Add equations 2 and 3, including Hrxn values
Divide by 4 to get result on a per-mole basis.
2007-11-19 18:53:10 · answer #2 · answered by cattbarf 7 · 0⤊ 0⤋
Can't you use Phosphorous pentachloride as an oxidizer in methcathinone?
2007-11-19 18:54:31 · answer #3 · answered by Anonymous · 0⤊ 0⤋