[Rafovafo]

Hi there. First post so I am not sure whether I am doing this right or not, but anyway. I got an assignment from my chemistry teacher and I can't figure out this: Calculate the volume of oxygen after the annealing of 3g of potassium chlorate within the standard conditions. (also please bare with me as English is not my first language so I am not sure whether I am using the correct terms in it, sorry if not)

[chenbeier]

What is your work.

Develop chemical equation potassium chlorate to oxygen
According to the equation look up the ratio of them
Calculate the mole of the 3 g
Convert this to the ratio
Then compute the volume

[Rafovafo]

What is your work.

Develop chemical equation potassium chlorate to oxygen
According to the equation look up the ratio of them
Calculate the mole of the 3 g
Convert this to the ratio
Then compute the volume

Hi, thanks for the answer. Honestly I had no idea how to start this assignment at all. Also, if possible, could you maybe describe what you answered in a bit more detail? Translating this to Croatian doesn't give me the best results, although I do think I know what you meant, and if so I should get this:

2KClO3 (s)  --> 2KCl (s) + 3O2 (g)

M(KCl) = Ar (K) + Ar (Cl) = 74.55

n(KCl) = m/M = 0.0402 mol

n(KCl)/n(O2) = 2/3

(O2) = 3n(KCl)/2

n(O2)=  0.0603 mol

and finally V0m = V0/n = 22.4/0.0603 = 0.0603 = 371.5L
however this seems like a huge amount of gas, what is the mistake in here?

edit:
First of all a friend told me its supposed to me n(KClO3)/n(O2) not n(KCL)
That led me to M(KClO3) = 122.55 and n(O2)=0.036
I also just realized its supposed to be V0m*n = 0.8064
Is that the right answer?

[chenbeier]

0,82 l is right answer.

2 KClO3 ..3 O2
1 KClO3....1.5 O2
3g KClO3  . 0,0245 mol ..0.036 mol O2
0.036 mol ...0.822  l

[Borek]

3 g is the mass of potassium chlorate that decomposed, not produced KCl.

and finally V0m = V0/n = 22.4/0.0603 = 0.0603 = 371.5L

Not sure where you got the formula from, but it is wrong - the volume is directly proportional to the number of moles, so you should multiply, not divide.