Question

How many moles of oxygen will be released when 250.0 grams of KClO3 is thermally decomposed ? 2KClO3 --> 2KCl+3O2<br /><br /> (Must be made to fit into this chart)

Answer 1

Molar mass KClO₃ = 122.5 g/mol and O₂ = 32.0 g/mol

2 KClO₃ ----------------> 2 KCl + 3 O₂

2 * 122.5 g KClO₃ ---------> 3 * 32 g O₂
250.0 g KClO₃ ------------> ?

mass of O₂ = 250.0 * 3 * 32 / 2 * 122.5

mass of O₂ = 24000 / 245

mass of O₂ = 97.959 g

number of moles O₂ :

1 mole --------- 32.0 g
? mole -------- 97.959 g

moles = 97.959 * 1 / 32.0

= 97.959 / 32.0

= 3.061 moles of O₂

hope this helps!