Question

a 5.00g sample of a hydrate of barium chloride was heated, and only 4.30g of the anhydrous salt remained. what is the formula of the hydrate?

Answer 1

how many moles of BaCl2 is in 4.3g?
how many moles of H2O is in .70g?

now look at the ratio. If there were 7 times as many moles of water as BaCl2, the formula would have been BaCl2.7H2O

Answer 2

thanks!!