Question

50 g of zinc blende (znS) containing only silica as impurity is roasted to convert all the znS in itto znO the result in decrease in mass of 6g due to roasting the weight of the impurity in the sample is (zn=65.4)

Answer 1

@open_study1 , this stuff is too hard...

Answer 2

I'm in 9th grade bro, not enrolled in general chem.

Answer 3

the ans=13.5g

Answer 4

plz solve for it

Answer 5

The reactions is: 4 ZnS + SiO2 + O2 ----> 4 ZnO + 4 S + Si

Answer 6

ok then

Answer 7

plz go on

Answer 8

http://openstudy.com/study#/updates/4fb249cce4b055653428082b

Answer 9

what do you want to find anyway?

Answer 10

find the weight of the impurity in the sample is ?

Answer 11

man this is way too hard -_______- but yes first you need to get the equation of the reaction then find the mole

Answer 12

@open_study1 I found a way to do the problem, but I have another answer, is 15.7 gr, and I found you are getting your problems from this book http://goo.gl/tix97 Let me show you my answer

First you have to write down the chemical equation which is \[4 ZnS + 3 SiO _{2} + 3 O _{2} --> 4 ZnO + 3 Si + 4 SO _{2}\]

Then you have to convert the moles to grams so it will be easier to solve, that gives us this equation: \[390 ZnS + 180 SiO _{2} + 96 O _{2} --> 325 ZnO +84 Si + 256 SO _{2}\]

Then you know that the total mass of the \[ZnS + SiO _{2}=50\] so we will name x for the mass of ZnS and y for the mass of SiO2.

After this is just simple math, you have the chemical relationship from the equation: \[390 ZnS - 180SiO _{2}\] as \[x - y\]

So we conclude that \[x+0.4615x=50\]
The results are:\[x=34.21 gr, y=15.7 gr\]

if you look for the mass of the ZnO you will find that is 28.508 gr, which is 6 gr less than the initial mass of the ZnS.

I hope it's correct, if you found another way to do it please share it!