Could you help me with this please

Question

Could you help me with this please. % chlorine in substance was measured at 12.3 %. %chlorine in a whole mixture was measured at 0.095%. M.w of a substance is 818.5 with 4 chlorine atoms in. What is the percentage of substance present in a whole mixture?

Answer 1

This is just a matter of using ratios to determine this.  

 

(x parts Cl / y parts substance) = 0.123

 

0.00095 = (x parts Cl / z parts mixture)

 

You can substitute one equation into the other to find that the percentage of y in z is 0.77%