Reduction half equation

[Studyinghard]

hey,

(IO3)- to I-

reduction half equation. How do i do this.

thanks

[Edmund]

Add three to right side to balance Oxygen



Now add to the left side to balance Hydrogen



And finally add 6 electrons to the left side to balance the charge

[Studyinghard]

hm okay i think i get that..what about this question. stupid freking practice exams i think are trying to screw my mind.


2KNO3 (s) ----> 2KNO2(s) + O2 (g)

1.01g of potassium nitrate was decomposed.

calculate amount of mol of Oxygen produced.

answer says 0.02. wtf?

[Edmund]

First you find the moles of potassium nitrate which is 0.00999 mol

Looking at mol ratio, there will be 0.5 x 0.00999 = 0.004995 mol of O2


Now looking at KNO2, there will be 0.00999 mol of (1:1 ratio)
But how many O2? According to equation, there's two NO2. Therefore the total number of O2 is 2, so number of moles is 2 x 0.00999 = 0.01988 mol

Adding all up, 0.004995 + 0.01988 = 0.02

[Studyinghard]

First you find the moles of potassium nitrate which is 0.00999 mol

Looking at mol ratio, there will be 0.5 x 0.00999 = 0.004995 mol of O2


Now looking at KNO2, there will be 0.00999 mol of (1:1 ratio)
But how many Oxygen? According to equation, there's two . Therefore the total number of O2 is 2, so number of moles is 2 x 0.00999 = 0.01988 mol

Adding all up, 0.004995+0.01988 = 0.02

:S why would you times it by 2. shouldnt u halve it? cuz the mole of oxygen is 1.

[Edmund]

Now looking at KNO2, there will be 0.00999 mol of  (1:1 ratio)
But how many Oxygen? According to equation, there's two . Therefore the total number of O2 is 2, so number of moles is 2 x 0.00999 = 0.01988 mol

This is for the oxygen in the KNO2 molecule. In the equation, it shows 2KNO2, which means two sets of O2, so we times the moles by 2.

I think the question is asking for the total amount of oxygen produced which includes the one in KNO2?

(Sorry latex doesnt seem to be working)

[Studyinghard]

Now looking at KNO2, there will be 0.00999 mol of  (1:1 ratio)
But how many Oxygen? According to equation, there's two . Therefore the total number of O2 is 2, so number of moles is 2 x 0.00999 = 0.01988 mol

This is for the oxygen in the KNO2 molecule. In the equation, it shows 2KNO2, which means two sets of O2, so we times the moles by 2.

I think the question is asking for the total amount of oxygen produced which includes the one in KNO2?

(Sorry latex doesnt seem to be working)

oh so im confusing myself with the oxygen gas produced and they are asking for the oxygen solid produced?

[Edmund]

Now looking at KNO2, there will be 0.00999 mol of  (1:1 ratio)
But how many Oxygen? According to equation, there's two . Therefore the total number of O2 is 2, so number of moles is 2 x 0.00999 = 0.01988 mol

This is for the oxygen in the KNO2 molecule. In the equation, it shows 2KNO2, which means two sets of O2, so we times the moles by 2.

I think the question is asking for the total amount of oxygen produced which includes the one in KNO2?

(Sorry latex doesnt seem to be working)

oh so im confusing myself with the oxygen gas produced and they are asking for the oxygen solid produced?

I think so, I can't get 0.02 if it's just the gas....