Question

Reaction between potassium chlorate and red phosphorus?

The reaction between potassium chlorate and red phosphorus is highly exothermic and takes place when you strike a match on a matchbox. If you were to react 52.9 g of potassium chlorate (KClO3) with red phosphorus, how many grams of tetraphosphorus decaoxide (P4O10) would be produced?

KClO3 (s) + P4 (s)  P4O10 (s) + KCl (s) (unbalanced)

Thanks! Please Explain!

Answers

balanced equation is 10 KCLO3 + 3 P4 = 3 P4O10 + 10 KCL

molecular wt of KClO3 is 39.1 + 35.453 +3 (16) = 122.55 g/mol

moles of KClO3 is 52.9g/122.55g/mol = 0.4316 mol

from balanced eqn there are 3 mols of P4O10 per 10 mole of KCLO3, so

0.4136 mol (3/10) = 0.1295 mol P4O10

molecular weight of P4O10 is 4(30.974) + 10(16) = 283.9 g/mol

0.1295mol (283.9 g/mol) = 36.8 gram P4O10

#1