[gildude86]

my questions says...from the weight of BaSO4 you obtained, calculate the weight of pure BaCl2. 2H20 in the impure sample you used in the reaction with sulfuric acid.

i had .424g BaSO4 ...molecular mass of BaSO4 is 233.392  and mm of BaCl2. 2H20 is 244.37..idk wat to do....oh and i had 5.911 g of bacl2 but thats the one with impurities.

[Borek]

Describe experiment that you did, write reaction equation, and use English (just to not break forum rules)

[gildude86]

i prepared barium chloride dihydrate from crude barium carbonate.. I added hydrochloric acid to the carbonate to make the barium chloride. Then I evaporate the solution to allow some solid crystals to appear and filtered it. after having the barium chloride...i mixed it with sulfuric acid to make barium sulfate.

[AWK]

To find a percent purity, you should take a known mass of your BaCl2.H2O

[gildude86]

yea my mass of the bacl2 . 2h2o was 5.911g

[Borek]

There are two identical keys on both sides of your keyboard, they are marked Shift and they are used to write capital letter whenever necessary.

Now, write reaction equation explaining where did the precipitate came from.

[gildude86]

 BaCl2 (aq) + H2SO4 (aq) ----> BaSO4(s) + 2HCl (aq)

[Borek]

OK. You know mass of the precipitate - to calculate mass of barium chloride you need some simple stoichiometry. Try.

[gildude86]

yea i tried that i get .443g but i dont knw wat to do from there to get the percent purity

[gildude86]

is it just actual over theoretical x 100% to find purity?

[Borek]

Please remember about this Shift/English thing.

Do you know how to calculate percent composition of sample? Just do it (you will have to convert mass of barium chloride to mass of barium chloride dihydrate, but that's not more complicated than what you already did calculating mass of chloride from mass of sulfate).

Looks to me you have way too low mass of sulfate, but we will get there in a few posts from now probably.

[Borek]

is it just actual over theoretical x 100% to find purity?

What do you mean by theoretical?