If 125 grams of KClO3 decomposes completely, how many moles of oxygen gas is produced?
To find the number of moles of oxygen gas produced when 125 grams of KClO3 decomposes completely, we need to follow a few steps:
Step 1: Determine the molar mass of KClO3.
The molar mass of KClO3 can be calculated by summing up the atomic masses of its constituent elements: potassium (K), chlorine (Cl), and oxygen (O). The atomic masses are found on the periodic table.
- The atomic mass of K is approximately 39.10 grams/mol.
- The atomic mass of Cl is approximately 35.45 grams/mol.
- The atomic mass of O is approximately 16.00 grams/mol.
So, the molar mass of KClO3 is:
(1 x K) + (1 x Cl) + (3 x O) = (1 x 39.10) + (1 x 35.45) + (3 x 16.00) = 122.55 grams/mol.
Step 2: Calculate the number of moles of KClO3.
The number of moles of KClO3 can be found using the formula:
moles = mass / molar mass.
Here, the mass is given as 125 grams, and the molar mass of KClO3 is 122.55 grams/mol.
So, moles of KClO3 = 125 grams / 122.55 grams/mol.
Using a calculator, we can determine that moles of KClO3 ≈ 1.019 mol (rounded to three decimal places).
Step 3: Determine the stoichiometry of the reaction.
The balanced chemical equation for the decomposition of KClO3 is:
2 KClO3 → 2 KCl + 3 O2
From the equation, we see that for every 2 moles of KClO3, 3 moles of O2 are produced.
Step 4: Calculate the moles of O2 produced.
We've determined that there are 1.019 moles of KClO3.
Using the stoichiometry from the balanced equation, we can calculate the moles of O2 produced by setting up a ratio:
1.019 mol KClO3 x (3 mol O2 / 2 mol KClO3) = 1.529 mol O2
Therefore, when 125 grams of KClO3 decomposes completely, approximately 1.529 moles of oxygen gas (O2) are produced.
figure moles of KClO3, then three halves times that.
MolesKClO3=125g/122.5
moles O=3*125/122.5
molesO2= 3/2 * 125/122.5