Mole Concept + Stoichiometry

[anthropos]

The following shows two stages in which the raw materials, zinc blende, ZnS, is converted to the metal zinc.

 

2ZnS (s) + 3O2 (g) --> 2ZnO (s) + 2SO2 (g)

ZnO (s) +C (s) --> Zn (l) + CO (g)

 

194g of znc blend is used for this extraction process. The mass of zinc recovered from it is 125g.

Write the overall reaction equation, with state symbols of this extraction process.

 

 

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11.1 g of calcim chloride is added to 100cm3 of water. Calculate its concentration in a) g/dm3 and b) mol/dm3.

 

The thing i want to ask is :

 

Concentration (g/dm3) = Mass of solute (g) / Volume of solution in dm3

 

Therefore, do we use the volume of water only or use the volume of the CaCl2 + H20?

[anthropos]

um...anyway...ignore the second question. I have asked my teacher about it and she said that there was something wrong with it...haha...

[LucidDreamer]

Isn't the overall reaction just: 2ZnS (s) + 3O2 (g) + C (s)--> ZnO (s) + 2SO2 (g) +Zn (l) + CO (g)

It's been awhile since I heard the term overall equation, but don't you just cross out all the terms in common with the products from the first reaction and the reactants from the second reaction. In this case you can remove one ZnO (s) from both equations.