The average the natural abundances of the various isotopes of carbon to arrive at the fractional mass.
The computation for this problem is:
(1.55x10^4 / 1.0x10^3) x 19.8 mm Hg
= 15.5 x 19.88 mm Hg
= 308.14 mm Hg decrease
= 308.14 x 0.05 C = 15.407 deg C
deduct this amount to 100
100 – 15.407 = 84.593 C
ANSWER: 85 deg C (rounded to 2 significant figures)
I believe that the answer is D.
I hope this helps. :)
Molecules in a gas will have more movement than molecules in a solid. This is because the molecules in solid matter are packed very tightly together to maintain its shape, whereas with gases they are spaced much further apart and fairly free to move. Hope this helps!