[bruhow]

I have a project where I am designing a mission to Mars.

I want students to test a “Mars” rock to see if it is a sulfate—which means it was formed in the presence of water.
The best way I can think of is to scrape a piece of gypsum into water in a test tube and shake it up, add a few drops of HCl, and then a squirt of Barium Chloride—which should precipitate and make the water turn milky.
1.   Will scrapes in water with HCl produce the reaction I need?
2.   What kind of HCl would be safest to use?
3.   What kind of Barium Chloride would be safest to use? (Here is an MSDS http://www.sciencestuff.com/msds/C1284.pdf)
4.   Are there alternative ideas/ or safer approaches? Or am I not even in the right ballpark?

On the HCl and BaCl, these can be bought from different supply houses in all different forms—as crystals, as toilet bowl cleaner, in various percentages/ normalities (example: http://www.sciencestuff.com/chemicals/H1.shtml ). I don’t have idea what to get. Really need some advice here.

The students will be working with rubber gloves on, inside a glovebox (no means of external ventilation)—so this is safe enough. I am more concerned with the part-time helpers who open up and setup the glovebox after hours who receive no safety training.

[Borek]

Sorry to be so blunt, but why are you trying to design an experiment if you have no idea how to do it? Questions you asked suggest you have no chemistry training, as calculating what to expect in your setup is something that is taught in GenChem101.

[Arkcon]

I'm confused too ... is this an exam or homework theoretical problem, or a schoolroom lab practical?  You have, theoretically I presume, transported rock samples from Mars, and you can't afford reagent grade chemicals?  I was pretty excited by the premise, I though you were going to transport the reagents to Mars and have a robot work there.  Now that would be cool.

[bruhow]

This is an activity to be used in a middle school STEM summer camp. My highest level of Chemistry was two years of college Chem as a pre-med. That is why I asked for help, especially in the safety factor. I can afford whatever is necessary. I am hoping someone can provide some advice on the safest kind of HCl and BaCl to buy that will do what I need it to do. The main reason I am doing it is for the gee-whiz cool factor. The idea of scraping a rock and running a test on it that actually works is what I am going for. I am open to other ideas. The point of the activity is to have a variety of geological specimens and the students to separate them into two groups-- those formed under aqueous processes and those that weren't. By running a sulfate test I am able to determine for instance whether the specimen is sandstone or olivine.