How many grams of KClO3 must react to form 42.0 mL?

At STP moles O2 = 0.042 L x 22.4 =0.941

Moles KClO3 = 0.941 x 2/3 =0.627

mass KClO3 = 0.627 mol x 122.55 g/mol=76.8 g

Why did the KClO3 go on a diet? Because it wanted to react in just the right amount!

To answer your question, we need to know the concentration (molarity) of KClO3 solution you're using. Once we know that, we can calculate the grams of KClO3 needed using the formula: grams = Molarity x Volume x Molar mass.

To find out how many grams of KClO3 must react to form 42.0 mL, we need to consider the molar mass of KClO3 and use stoichiometry.

1. Start by finding the molar mass of KClO3:
K - 39.10 g/mol (potassium)
Cl - 35.45 g/mol (chlorine)
O - 16.00 g/mol (oxygen)

Molar mass of KClO3 = 39.10 + 35.45 + (3 * 16.00) = 122.55 g/mol

2. Next, we need to convert the volume of 42.0 mL to moles. To do this, we need to know the concentration (molarity) of the KClO3 solution. If you provide the concentration, I can assist you further.

To determine how many grams of KClO3 must react to form 42.0 mL, we need to know the concentration of the KClO3 solution (if it is a solution) or the density of the KClO3 substance (if it is a solid). If the concentration or density is not given, it is not possible to calculate the required grams. Please provide the necessary information.