Chemistry paper1 M/J 2003

[1992]

Hello, i need help in these 4 questions please : Q10, 20, 27, and 33.

 

[beacon_of_light]

q10:

H2 + I2 -------> 2HI

initial moles: 0.2 0.15 0

moles reacted: 0.13 0.13

moles at equilibrium: 0.07 0.02 0.26

here's hw i calculated this!

0.26 moles of hydrogen iodide are present at equilibrium... use molar ratios to find the moles of H2 and I2 reacted.

2HI reacted with 1H2
0.26HI would react with 0.26/2=0.13 moles of H2 ...similarly 0.13 moles of I2 react...

so Kc = (0.26)^2 / (0.07 x 0.02)

 

[beacon_of_light]

q20 & 27: explained that before in another topic. check that out!

for q33..draw hess's cycle in each case,,,and following the arrows....draw out ur conclusion...eg...if both are atomised...so the cycle would be graphite to diamond to atoms or directly from graphite to atoms..........

deltaH = delta H(atom of graphite) - deltaH(atom of diamond) ..and since delta H > 0 ...so obviously diamond has low enthalpy change of atomisation....do the rest in the same way!