Question

How many grams of $CS2$are needed to produce 6 moles of sulfur dioxide? $CS2+\,{{O}_{2\,}}\to \,C{{O}_{2}}\,+\,S{{O}_{2}}$

Answer 1

Hint:This question is based on the concept of basic stoichiometry and balancing of chemical equations. In this question we will firstly balance the given equation and then will perform the basic stoichiometry and unitary method.

Complete answer:
The balanced chemical reaction can be represented as $C{{S}_{2}}\,+\,3{{O}_{2\,}}\to \,C{{O}_{2}}\,+\,2S{{O}_{2}}$
The balanced reaction tells us that for every one mole of $C{{S}_{2}}$consumed, three moles of sulfur dioxide $(S{{O}_{2}})$is formed
In the question we are asked to find out the quantity of $C{{S}_{2}}$required to produce $6$moles of $S{{O}_{2}}$
Now we know that six is three times of two
Therefore, we will multiply the above balanced reaction by $3$.
 By this we will get $6$moles of $S{{O}_{2}}$ on R.H.S of the equation. Corresponding to it on RHS we will get the moles of $C{{S}_{2}}$that are required to produce$6$moles of sulfur dioxide.
The reaction can be written as
$3C{{S}_{2}}\,+\,9{{O}_{2\,}}\to \,3C{{O}_{2}}+\,6S{{O}_{2}}$
From the above reaction we can infer that $3$moles of carbon disulfide are required to produce $6$moles of sulfur dioxide.
But we need to find the quantity of $C{{S}_{2}}$in grams. For this we need to convert $3$ moles of carbon disulfide to grams.
We know that one mole of any substances contains mass equal to its molar mass.
Therefore, if we multiply 3 moles of carbon disulfide with its molar mass, we will get the quantity of carbon disulfide in grams.
Molar mass of $C{{S}_{2}}\,=\,76.139\,$g/mol
$\Rightarrow \,3\,\times \,76.139\,=\,228.417$grams of $C{{S}_{2}}$
Hence, $228.417$grams of $C{{S}_{2}}$are needed to produce $6$moles of $S{{O}_{2}}$.

Note:Stoichiometry becomes a sticking spot for many students due to some common errors. To avoid them make sure that the chemical equation is properly balanced. Determine the starting and ending points to figure out the necessary conversions. Calculate the molar masses of substances properly.