Question

A) A plot of link vs 1/T for a reaction gives a slope of 4160 and intercept of 1.75. Find the ΔH° for this reaction.

B) The first order decay of radon has a half-life of 3.823 days. How many grams of radon remain after 7.22 days if the sample initially weighs 250.0 g?

C) Determine the ΔHsolute for KBr if the ΔHsolution (KBr)= +19.9 kj/mol and the ΔHhydration(KBr) = -670kj/mol

Answer 1

A)
slope of ln K vs 1/T is (-ΔH/R)
So,
(-ΔH/R) = 4160
(-ΔH/8.314) = 4160
ΔH = -34586 J/mol
= -34.6 KJ/mol
Answer: -34.6 KJ/mol

B)
1st find the rate constant using relationship between rate constant and half life for 1st order reaction
k = 0.693/half life
= 0.693/3.823
=0.1813 day-1

use:
[A]= [Ao]*e^(-k*t)
= 250.0*e^(-0.1813*7.22)
= 67.54 g
Answer: 67.54 g

none of your question are related. they all are different questions

I am allowed to answer only 1 question at a time