One small-scale laboratory method for preparing oxygen is to...

One small-scale laboratory method for preparing oxygen is to heat potassium chlorate in the presence of a catalyst: $2 \mathrm{KClO}_{3}(\mathrm{s}) \rightarrow 2 \mathrm{KCl}(\mathrm{s})+3 \mathrm{O}_{2}(\mathrm{g}) .$ Find the STP volume of oxy- gen that can be produced by $5.74 \mathrm{g} \mathrm{KClO}_{3}$.

One small-scale laboratory method for preparing oxygen is to heat potassium chlorate in the presence of a catalyst:
$2 \mathrm{KClO}_{3}(\mathrm{s}) \rightarrow 2 \mathrm{KCl}(\mathrm{s})+3 \mathrm{O}_{2}(\mathrm{g}) .$ Find the STP volume of oxy-
gen that can be produced by $5.74 \mathrm{g} \mathrm{KClO}_{3}$.

Key Concepts

Stoichiometry

Stoichiometry is the calculation of reactants and products in chemical reactions. It uses the relationships expressed in a balanced chemical equation to determine the amounts of substances involved, converting between masses, moles, and numbers of particles using molar ratios.

Mole Concept and Mass-to-Mole Conversions

The mole concept is a fundamental chemical idea that relates the mass of a substance to the number of particles it contains through its molar mass. This conversion is critical for translating a given mass of a substance into moles, which then facilitates the use of stoichiometric ratios in chemical calculations.

Molar Volume at STP

The molar volume at standard temperature and pressure (STP) refers to the volume occupied by one mole of an ideal gas under these conditions, typically taken as 22.4 liters. This concept allows for the direct conversion between the moles of a gas produced and its volume at STP, which is essential in gas evolution reactions.

Decomposition Reactions

Decomposition reactions involve a single compound breaking down into two or more simpler substances. Understanding these types of reactions is important, as they often yield gases or simpler products that can be quantified and analyzed through stoichiometric methods.

Catalysis

Catalysis involves the use of a substance that increases the rate of a chemical reaction without being consumed in the process. In chemical reactions, catalysts lower the activation energy required and are crucial for enhancing reaction efficiency, although they do not alter the overall stoichiometry of the reaction.

Transcript

00:02 In this problem, we are given a balanced equation to begin with.

00:07 We have 2 kcl -03 decomposes to form 2kcl plus 3 -02, and the oxygen is, of course, a gas.

00:27 We're also told that this is at stp, standard temperature and pressure.

00:32 And we are given 5 .74 grams of kcl -03, and we want to know how many liters of the oxygen we can produce.

00:48 So this is our problem.

00:50 We are going to have to do some stoichiometry to get from grams of kcl -o -3 to liters of oxygen.

00:57 Let's plan this out for a moment.

01:00 We know that we can use molar mass to go from grams to moles of the kclo3.

01:06 Then we know that we can use stoichiometry or the mole ratio from the balanced equation to get us to moles of the oxygen.

01:20 And finally, we can use molar volume at standard temperature pressure of 22 .4 to get us to liters of the oxygen.

01:28 So that's our plan.

01:30 Let's go ahead and get started.

01:33 Starting with 5 .74 grams of the kcl -3.

01:39 I said that my first step was to divide by the molar mass to convert to moles of kclo3.

01:50 From the periodic table, the molar mass of kclo3, adding together a potassium, a chlorine, and three oxygen, i get 122 .55 grams of kclo3.

02:11 All right...

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