If all of the chloride in a 3.512g sample of an unknown metal chloride is precipitated as AgCl with 70.90mL of 0.2010M AgNO3, what is the percentage of chloride in the sample?

How do you start this?

Question

If all of the chloride in a 3.512g sample of an unknown metal chloride is precipitated as AgCl with 70.90mL of 0.2010M AgNO3, what is the percentage of chloride in the sample?

How do you start this?

aaronq · Answer

find the moles of AgCl (or just $Ag^+$), which are equal to moles of $Cl^-$.
Find the mass, then find the percent of it in the 3.512 g sample.

anonymous · Answer

I got moles of Ag, which is .2010 (moles/.0709) = .0143  moles of Ag
then, 0.143 moles Ag (108g Ag/1 mole Ag) = 1.540 g Ag

is that correct so far?

aaronq · Answer

no, you don't need to find the mass of Ag, you need mass of $Cl^-$

anonymous · Answer

so instead of using 108g Ag, i should just use 35.5g Cl? I did that and got 0.508g Cl

aaronq · Answer

yep. now find what percent of the sample that is

anonymous · Answer

to do that, i do (3.512/0.508) * 100?

aaronq · Answer

hm almost it should be (0.508/3.512) * 100

anonymous · Answer

thank you!

aaronq · Answer

no probs !