Question

Potassium chlorate, KClO3, decomposes into potassium chloride, KCl, and oxygen, O2, when heated, as shown in the equation:
2KClO3(s) --> 2KCl(s) + 3O2(g)
The initial mass of potassium chlorate was 24.5 g. After heating, the mass of oxygen was 4.5 g.
How many more grams of O2 need to be produced for the decomposition of KClO3 to be complete?

Answer 1

There are a couple ways to approach this, but the most direct way would be to find the 100% theoretical yield of the 24.5g of potassium chlorate. You have a partial yield of 4.5g of O2. That's only after SOME of the potassium chlorate decomposes. You have to find out how much O2 would be produced when ALL of the potassium chlorate decomposes. Then subtract the 4.5g of O2 to find out how much more is produced.

Answer 2

@jfraser but isn't the equation backwards then?

Answer 3

@Somy do you know how I start this?

Answer 4

@Abmon98

Answer 5

oh yeah well
first step find moles

Answer 6

.204 moles of Potassium Chlorate

Answer 7

i am not sure of my working.

Answer 8

@Abmon98 so I do:
.2 x (3/2) = .3
.3 x 32 = 9.6g
9.6 - 4.5 = 5.1g

Answer 9

yes @dsood15

Answer 10

thats right :)

Answer 11

thanks!

Answer 12

your welcome :D