Question

9) How many moles of oxygen are formed when 58.6 g of KNO3 decomposes according to the
following reaction? The molar mass of KNO3 is 101.11 g/mol.
4 KNO3(s) ? 2 K2O(s) + 2 N2(g) + 5 O2(g)
9) _______
A) 0 .724 mol O2
B) 0 .580 mol O2
C) 1 .73 mol O2
D) 0 .290 mol O2
E) 1 8.5 mol O2

Answer 1

This is a fairly straightforward two-step problem. Our first step is to convert the given grams of reactant (KNO3) to moles:

Next, we use the balanced reaction equation (given in the problem) to see that for every 4 moles of KNO3 that react, we get 5 moles of O2 (Oxygen). Usin gthis information, we can determine how many moles of Oxygen we will get when our given 0.579 moles of KNO3 react:

This is our final answer which corresponds with choice "A"

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