Estimate the average `S -F` bond energy in `SF_(6)`. The values of standard enthalpy of formation of `SF_(6)(g), S(g)`, and `F(g)` are `-1100, 275`, and `80 kJ mol^(-1)`, respectively.

Options

A. 301 kJ/mol
B. 320 kJ/mol
C. 309 kJ/mol
D. 280 kJ/mol

Answer

C

Explanation

`S(g) + 6F(g) rarr SF_(6)(g)`
`Delta H_(f) (s) + 6Delta H_(f)(F) - 6(S - F) B.D = Delta H_(f) = Delta H_(f) (SF_6)`
`275 + (6 xx 80) -6(S - F) = -1100`
`275 + 480 + 1100 = 6(S -F)`
`(1855)/6 = (S - F) = 309 kJ//mol`