If 120. grams of KClO3 reacts, how many grams of oxygen are produced?

2KClO3 ==> 2KCl + 3O2

mols KClO3 = grams/molar mass.
Using the coefficients in the balanced equation, convert mols KClO3 to mols O2.
Now convert mols O2 to grams. g = mols O2 x molar mass O2 = ?

To determine the number of grams of oxygen produced when 120 grams of KClO3 reacts, we need to use the balanced chemical equation for the reaction. The balanced equation for the decomposition of KClO3 is:

2 KClO3(s) → 2 KCl(s) + 3 O2(g)

From the balanced equation, we can see that 2 moles of KClO3 produce 3 moles of O2. To solve the problem, follow these steps:

Step 1: Convert grams of KClO3 to moles.
To convert grams to moles, we use the molar mass of KClO3. The molar mass of KClO3 is obtained by adding up the atomic masses of each element in the compound:
K: 39.1 g/mol
Cl: 35.45 g/mol
O: 16.00 g/mol (x 3 because there are three oxygen atoms in KClO3)

Molar mass of KClO3 = 39.1 + 35.45 + (16.00 x 3) = 122.55 g/mol

120 grams of KClO3 × (1 mol KClO3 / 122.55 g KClO3) = 0.979 mol KClO3

Step 2: Use the mole ratio from the balanced equation to find the moles of oxygen produced.
From the balanced equation, we know that 2 moles of KClO3 produce 3 moles of O2.

0.979 mol KClO3 × (3 mol O2 / 2 mol KClO3) = 1.469 mol O2

Step 3: Convert moles of oxygen to grams.
To convert moles to grams, we multiply the molar mass of oxygen, which is 32.00 g/mol.

1.469 mol O2 × 32.00 g/mol = 46.93 grams of O2

Therefore, when 120 grams of KClO3 reacts, approximately 46.93 grams of oxygen are produced.