AH2
AH
The enthalpy diagram to the right represents a set
of thermochemical equations. Which set of
equations could it represent?
A+BCAH = - 500 kJ
C + D →E + 2F AH2 = 100 kJ
F+D →BAH3 = 200 kJ
CA+B →CAH = 800 kJ
C + D + E + 2F AH2 = - 200 kJ
F+D+BAH3 = - 300 kJ
A+DE AH = 500 kJ
DF AH2 = - 300 kJ
E +F
AH
ΔΗΧn
DONE
A + 2D
(Arrow lengths are not to scale.)

A + B  C   H1 = 800 kJ

C + D  E + 2F   H2 = - 200 kJ

F + D  B   H3 = - 300 kJ

Explanation:

Just answered it correctly on EDGE

Option B

---> A + B Right arrow. C   Delta.H1 = 800 kJ

C + D Right arrow. E + 2F   Delta.H2 = - 200 kJ

F + D Right arrow. B   Delta.H3 = - 300 kJ

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol