Answer on Question #54212 – Chemistry – General chemistry
Question:
How many grams of O2 are produced in the decomposition of 43.4g KClO3? 2KClO3(s) --> 2KCl(s) + 3O2(g)
Answer:
First of all, the number of moles of KClO3 should be found:
ν(KClO3) = m(KClO3)/M(KClO3) , where m(KClO3) – the mass of KClO3, M(KClO3) – the molar mass of
KClO3.
Thus, ν(KClO3) = 43.4 g/122.55 g mol-1 = 0.3541 moles
According to the reaction, the amount of formed oxygen is in 3 times more than KClO3.
Therefore ν(O2) = 3 ν(KClO3) = 3 × 0.3541 moles = 1.0624 moles
The mass of oxygen equals:
m(O2) = ν(O2) M(O2), where M(O2) – the molar mass of oxygen.
Finally, m(O2) = 1.0624 moles × 32 g mol-1 = 34 g
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