Question

Potassium chlorate decomposes according to the following chemical equation:

2KCIO3 -- 2KCI + 3O2
If you start with 458g of KCIO3 , what mass (g) of O2 will be produced?
83.71 L O2
179.39 L O2
687 L O2
67.2 L O2

Answer 1

179.4 g of oyxgen will be produced.

Option 2.

Be careful because the units says L instead of g

Step-by-step explanation:

Decomposition reaction:

2KClO₃ → 2KCl + 3O₂

2 moles of chlorate can decompose to 2 moles of chloride and 3 moles of oxygen.

We convert the mass to moles, and then we make the rule of three:

458 g / 122.55 g/mol =3.74 moles of chlorate

2 moles of chlorate can produce 3 moles of oxygen

Then, 3.74 moles of chlorate may produce (3.74 .3) / 2 = 5.60 moles of O₂

We convert the moles to mass → 5.60 mol . 32 g / 1mol = 179.4 g

Answer 2

179.39 grams of O2 will be produced (option 2 is correct)

Step-by-step explanation:

Step 1: Data given

Mass of KClO3 = 458 grams

Molar mass KClO3 = 122.55 g/mol

Molar mass O2 = 32.0 g/mol

Step 2: The balanced equation

2KCIO3 → 2KCI + 3O2

Step 3: Calculate moles KClO3

Moles KClO3 = mass KClO3 / molar mass KClO3

Moles KClO3 = 458 grams / 122.55 g/mol

Moles KClO3 = 3.74 moles

Step 4: Calculate moles of O2

For 2 moles KClO3 we'll have 2 moles KCl and 3 moles O2

For 3.74 moles we'll have 3/2 * 3.74 = 5.606 moles

Step 5: Calculate mass O2

Mass O2 = 5.606 moles * 32.0 g/mol

Mass O2 = 179.39 grams

179.39 grams of O2 will be produced (option 2 is correct)