How many grams of carbon disulfide are needed

Question

How many grams of carbon disulfide are needed to completely consume 83.6 L of chlorine gas according to the following reaction at 25 °C and 1 atm?

 

carbon disulfide ( s ) + chlorine ( g ) carbon tetrachloride ( l ) + sulfur dichloride ( s )

 

______grams carbon disulfide

Answer 1

Hello Hussein

 

This questions combines using (a) the ideal gas law, and (b) a stoiciometry calculation.  The first step is to write the balanced chemical reaction.

 

CS₂ (s)  +  4Cl₂ (g)   -->   CCl₄ (l)  +  2SCl₂ (s)

 

We are given 83.6 L of Cl₂ (g) at P = 1 atm, and T = 25 °C (25 + 273 = 295 K)

 

Using the ideal gas law, first calculate the # of moles of Cl₂ gas.

 

PV = nRT

 

n = PV / RT  = (1 atm x 83.6 L) / (0.0821 L atm mol^-1 K^-1  x  295 K)  =  3.45 mol Cl₂

 

Using the balanced chemical reaction, you now need to use stoichiometry to convert moles of Cl₂ to moles of CS₂.  From the reaction, you can see that for every 4 moles of Cl₂ that reacts, you need 1 mole of CS₂.  Therefore,

 

3.45 mol Cl₂  x  1 mol CS₂ / 4 mol Cl₂  =  0.863 mol CS₂

 

Finally, convert mol CS₂ to grams CS₂ using its molar mass (76 g/mol).

 

0.863 mol CS₂  x  76 g CS₂ / 1 mol CS₂  =  65.6 g CS₂