Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: 3 hours left please help

  1. Oct 18, 2004 #1
    Under special conditions, sulfur reacts with anhydrous liquid ammonia to form a binary compound of sulfur and nitrogen. The compound is found to consist of 69.6% S and 30.4% N. Measurements of its molecular mass yield a value of 184.3 g/mol. The compound occasionally detonates on being struck or when heated reapidly. The sulfur and nitrogen atoms of the molecule are joined in a ring. All the bonds in the ring are of the same length.
    a) Calculate the empirical formula and molecular formulas for the substance.
    b) Predict the bond distances between the atoms in the ring (Note: the S-S bond distance in the S8 rign is 2.05 A)

    c The enthalpy of formation of the compound is estimated to be 480 KJ/ mol. The Hf of S(g) is 222.8 KJ/mol. Estimate the average bond enthalpy in the compound.

    i did a but i drew the lewis dot diagram out with the S4N4 and it turned out there were 2 double bonds while the rest were single bonds. How does that work if the bond distances in the ring are the same length?

    as for c i have no idea how to do this.

    i think the formula is this 2 S2(g) + 4 NH3(l) -> S4N4 + 6 H2(g)

    I'm given the N-H bond enthalpies as 391 KJ/mol but that's according to gas. NH3 is a liquid. How am i suppose to solve this. Please help. thanks
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted