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In an experiment, potassium chlorate decomposed according to the following chemical equation. KClO3 → KCl + O2 (Molar mass of KClO3 = 122.5 g/mol; KCl = 74.55 g/mol; O2 = 31.998 g/mol) If the mass of KCl produced was 180 grams, which of the following calculations can be used to determine the mass of potassium chlorate decomposed? (180 × 2 × 74.55) ÷ (122.5 × 2) grams (180 × 3 × 74.55) ÷ (122.5 × 2) grams (180 × 2 × 122.5) ÷ (74.55 × 2) grams (180 × 3 × 122.5) ÷ (74.55 × 2) grams

Respuesta :

Answer:

The correct option is :

(180 × 2 × 122.5) ÷ (74.55 × 2) grams

Explanation:

Here , mole concept is applied

[tex]moles = \frac{given\ mass}{molar\ mass}[/tex]

Balance the equation first, it should be :

[tex]2KClO_{3}\rightarrow 2KCl + 3O_{2}[/tex]

(1 mole = Molar mass of the molecule)

( 2 mole = 2 x Molar mass)

This means , if 2 moles of KCl is produced then 2 moles of KClO3 should be decomposed

2 x Molar mass of KCl  is produced = 2 x Molar mass  of KClO3 is decomposed

Molar mass of KCl = 74.55 g/mol(given)

Molar mass of KClO3 = 122.5 g/mol(given)

If,

2 x 74.55 gram KCl = 2  x 122.5 gram KClO3

Then

1 gram of KCl

[tex]= \frac{2\times 122.5}{2\times 74.55}[/tex] of KClO3

So , 180 gram of KCl will produce ,

[tex]= \frac{2\times 122.5}{2\times 74.55}\times 180[/tex] of KClO3

=  295.77 gram

The mass of decomposition of  [tex]\rm KClO_3[/tex] has been given by [tex]\rm \dfrac{180\;\times\;2\;122.5}{74.55\;\times\;2}[/tex] grams. Thus option C is correct.

The given chemical reaction is:

[tex]\rm KClO_3\;\rightarrow\;KCl\;+\;O_2[/tex]

For the production of 1 mole of KCl, 1 mole of [tex]\rm KClO_3[/tex] has to be decomposed.

The mass of KCl produced = 180 grams.

Moles of KCl produced = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]

Moles of KCl produced = [tex]\rm \dfrac{180}{74.55}[/tex] moles

For the production of  [tex]\rm \dfrac{180}{74.55}[/tex]  moles of KCl the same of  [tex]\rm KClO_3[/tex] has to be decomposed.

Thus, the moles of  [tex]\rm KClO_3[/tex] has to be decomposed =   [tex]\rm \dfrac{180}{74.55}[/tex]  moles

Mass of   [tex]\rm KClO_3[/tex] has to be decomposed = moles [tex]\times[/tex] molecular weight

Mass of [tex]\rm KClO_3[/tex] has to be decomposed = [tex]\rm \dfrac{180}{74.55}[/tex]  moles [tex]\times[/tex] 122.2 grams.

For the production of 2 moles of KCl,  [tex]\rm KClO_3[/tex] has to be decomposed =

[tex]\rm \dfrac{180\;\times\;2\;122.5}{74.55\;\times\;2}[/tex] grams.

Thus, the mass of decomposition of  [tex]\rm KClO_3[/tex] has been given by [tex]\rm \dfrac{180\;\times\;2\;122.5}{74.55\;\times\;2}[/tex] grams. Thus option C is correct.

For more information about the decomposition reaction, refer to the link:

https://brainly.com/question/8009068