Question

A chemist measures the energy change ΔH during the following reaction:
2HgO (s) → 2Hg (l) + O2 (g), ΔH = 182.0 kJ
Use the information to answer the following questions.

(1) This reaction is:

a. endothermic.
b. exothermic.

(2) Suppose 72.8g of HgO react. Will any heat be released or absorbed?

a. Yes, absorbed.
b. Yes, released.
c. No.

(3) If you said heat will be released or absorbed in the second part of this question, calculate how much heat will be released or absorbed. Round your answer to 3 significant digits.

Answer 1

Answer:

1. The reaction is endothermic as the ΔH is positive. option A

2. molar mass of HgO =216.59

     mass of HgO = 72.8g

   no of moles of HgO = 72.8/216.59

                           = 0.336mol

2HgO (s) → 2Hg (l) + O2 (g), ΔH = 182.0 kJ

from the equation above ; moles of HgO will react and heat absorbed is 182KJ

0.336moles will require      (0.336*182)/2

                                         = 30.576KJ

Option a is correct.

3.  Heat absorbed = 30.6KJ (3.s.f)