Question

how many moles of kclo3 solid must be reacted according to the following balanced chemical reaction to transfer -34.2 kj of heat? 2 kclo3(s) → 2 kcl(s) + 3 o2(g) δh = -89.4 kj

Explanation:

Step1: Set up the mole - heat ratio

From the balanced equation \(2KClO_3(s)\to2KCl(s) + 3O_2(g)\), \(\Delta H=-89.4\ kJ\). This means that for every \(2\) moles of \(KClO_3\) reacted, \(- 89.4\ kJ\) of heat is transferred.
We can write the ratio as \(\frac{2\ mol\ KClO_3}{-89.4\ kJ}\)

Step2: Calculate the moles of \(KClO_3\)

We want to find the moles of \(KClO_3\) when \(q=-34.2\ kJ\).
Using the ratio from Step1: \(n =-34.2\ kJ\times\frac{2\ mol\ KClO_3}{-89.4\ kJ}\)

$$n=\frac{-34.2\times2}{-89.4}\ mol\ KClO_3=\frac{68.4}{89.4}\ mol\ KClO_3 = 0.765\ mol\ KClO_3$$

Answer:

\(0.765\)