Question

A chemist measures the energy change delta h during the following reaction: 2 HgO₍ₛ₎ → 2 Hg₍ₗ₎ + O₂₍g₎

ΔH = 182 kJ How much heat will be released or absorbed when 72.6 g of HgO reacts?

A. 15.24 kJ
B. 30.49 kJ
C. 45.73 kJ
D. 60.98 kJ

Answer 1

To find the amount of heat released or absorbed, we need to use stoichiometry. By calculating the number of moles of HgO and using the stoichiometry of the reaction, we find that 30.49 kJ of heat will be released.

Step-by-step explanation:

To calculate the amount of heat released or absorbed when a given amount of a substance reacts, we need to use the concept of stoichiometry. In this reaction, 2 moles of HgO react to form 2 moles of Hg and 1 mole of O₂.

The molar mass of HgO is 216.59 g/mol. Therefore, the number of moles of HgO in 72.6 g is:

Number of moles = mass / molar mass = 72.6 g / 216.59 g/mol = 0.335 mol

Since the reaction produces 182 kJ of heat for 2 moles of HgO, we can calculate the amount of heat produced for 0.335 mol using stoichiometry:

Amount of heat = (182 kJ / 2 mol) * 0.335 mol = 30.49 kJ

Therefore, the correct answer is B. 30.49 kJ.