Question

A gas of potassium chlorate molecules KClO3 all decompose into potassium chloride, KCl, and diatomic oxygen, O2. The products and reactants are in a closed container and can all be treated as ideal gases.A. Fill in the smallest possible integers that allows the stoichiometry of the reaction equation to be correct:__ KClO3 → ___ KCl ___ O2B. If there are N molecules of potassium chlorate in the initial state, how many product molecules are there

Answer 1

Answer: A. $2KClO_3\rightarrow 2KCl+3O_2$

B. $2.5\times N$ molecules of product.

Explanation:

According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

A. The balanced reaction for decomposition of potassium chlorate is:

$2KClO_3\rightarrow 2KCl+3O_2$

B. According to avogadro's law, 1 mole of every substance occupies 22.4 L at NTP, weighs equal to the molecular mass and contains avogadro's number $6.023\times 10^{23}$ of particles.

According to stoichiometry :

2 moles of reactant give 5 moles of products

Thus $2\times 6.023\times 10^{23}$ molecules of reactant give $5\times 6.023\times 10^{23}$ molecules of product

Thus N molecules of reactant give=  $\frac{5\times 6.023\times 10^{23}}{2\times 6.023\times 10^{23}}\times N=\frac{5}{2}\times N$ molecules of product.

Thus $\frac{5}{2}\times N=2.5\times N$ molecules of product are there.