Alright, I need some help on this assignment, and the hints and things don't help me at all, so I was wondering if someone could just assist me in the method for it. I honestly can't figure out what it wants me to do.

Question

anonymous · Answer

Here's the stuff it gives me:
 We have seen that arsenic can exist in many different chemical species. Suppose the only method you have available at your lab for determining arsenic content is the colorimetric method seen in the previous problem: AsO2- + Red-K9 ---> AsO2-Red-K9-.

Unfortunately, your samples also contain arsenate besides the arsenite that can be quantified with this analytical method.

Luckily enough you have L-cysteine available, a compound that can reduce the arsenate to arsenite according to the following reaction: AsO4-3 + 2 L-cysteine ---> AsO2- + 2 L-cystine.

What is the concentration of arsenic (in milligrams per liter) in this sample? (please, give your answer with three significant figures.)

Activity 1:   Design and perform an experiment to determine the molarity of arsenite and arsenate in the well sample.
The solution contains ___   molar of arsenite and ___   molar of arsenate.

Activity 2:   What is the concentration of arsenic in the well sample?    ___   mg/L As 

The ___ are what I need to fill in. It's a virtual lab, with samples and randomly generated answers. I can try and send a link if anyone wants it, but I'm just hoping the process is clearer to someone on here than it is to me.

aaronq · Answer

Do you have data? like masses or volumes?