Chemistry(I don’t get it and can you please add steps? Thank you)

Question

Here is the question

Potassium chlorate is sometimes decomposed in the laboratory to general oxygen. The reaction is 2KCIO3(s) -> 2KCI(s) + 3O2(g). What mass of 3KCIO3 do you need to produce 0.50 mol O2?

Answer 1

Iris,

Here are the steps to solve this problem.

1). Look at the balanced equation: 2KClO₃(s) --> 2KCl(s) + 3O₂(g)

2). Note that it takes TWO mols KClO₃ to produce THREE mols O₂. This is the mol ratio and it is important.

3). Knowing that we want to produce 0.50 mols of O₂, we can use this mol ratio to find the mols of KClO₃ that we need. Using dimensional analysis, we see the following:

0.50 mols O₂ x 2 mols KClO₃ / 3 mols O₂ = 0.333..mols KClO₃ needed

4). Now we simply convert mols KClO₃ to grams of KClO₃ using the molar mass of KClO₃ (122.5 g/mol)

0.333 mols x 122.5 g/mol = 40.8 g KClO₃ needed = 41 g (2 sig. figs.)