barium chloride dihydrate, BaCl2*2h2o, contains 2 moles of water molecules per 1 mole of BaCl2. however, water

Question

accounts for only 15% of the mass of this hydrated salt. Explain why water does not amount to 66% of the mass of this hydrate?

Answer 1

water does account for 66% if you are counting parts, there are two moles of water per one mole of BaCl2, but your question doesn't ask for parts, it asks for mass.

The mass of BaCl2 is found by adding the mass of one barium atom to two chlorine atoms.

2 chlorine atoms have a mass of 70.9 grams/mole (35.453 g/mole each)

1 barium atom has a mass of 137.33 grams/mole

for a total of 208.2 grams/mole for BaCl2

Water has a mass of 18.015 grams/mole (add up the parts, 2 hydrogens and one oxygen like I did for BaCl2 above)

Then divide the mass of each part of the compound by the mass of the whole compound:

For water: mass of the water (remember there are two water molecules) divided by mass of hydrated compound (BaCl2 with the two waters)

this is: (18.015 x 2) / 208.2 x 100 = 15%

For Barium Chloride: mass of the BaCl2 divided by mass of the hydrated compound (BaCl2 with the two waters)

this is: 137.33 / 208.2 x 100 = 85%

Checking your answer, the two percentages do add up to 100% so you did your calculations right and didn't leave any parts out.

Answer 2

Look at the atomic masses on the periodic table. If all 100 some odd atoms had the same mass then yes, that would be so.

But Ba and CL atom weight more than H and O.

Ba + 2*Cl = 137.3 * 2 (35.45)

2 (H 20) = 2 (1 + 2(16)

you can see how much more mass Barium Chloride has.

Answer 3

this is been a at the same time as for the reason that I did stoichiometry yet i might say one mole of water. Their elemental aspects are lighter and less difficult (it would take extra of them to equivalent a denser molecule like glucose or sodium chloride)

Answer 4

Yes, there are 2 molecules of water to every 1 molecule of barium chloride. But the barium chloride molecules are much heavier than water molecules so their weight takes up most of the dihydrate. By way of analogy, consider 2 ping pong balls in a sack with one golf ball. There are twice as many ping pong balls as there are golf balls, but most of the weight of the sack is from the golf ball.

Answer 5

you people are the biggest dorks.