Question

can someone help me on a chem question

Answer 1

How many grams of CaSO4.2H2O will contain 18.02 g of water?

Answer 2

can you elaborate?

Answer 3

Im trying to figure out how they got this answer

Answer 4

1 mole of CaSO4.2H2O weighs 172g and 1 mole of H2O weighs 18.02g

There are 2 moles of H2O in each mole of CaSO4 so in order to have 18.02g of water we need to have 1/2 x 172g of CaSO4

Answer 5

Look at the atomic weights:
Ca: 40.078
S: 32.06
O: 15.999
H: 1.008

\(CaSO_4\cdot \color{red}{2H_2O} \)

\(= 40.078 + 32.06 + 4 \times 15.999 + \color{red}{2(2 \times 1.008 + 15.999)} \)

\(= 172.16\) g

Of which, \(2 ( 2 \times 1.008 + 15.999) = 36.03\) g is from \(2H_2O\)

Since 172.16 g of the compound contains 36.03 g of \(H_2O\),
then dividing both by 2, 81.08 g of the compound contains 18.02 g of \(H_2O\).

Answer 6

which is 86g

Answer 7

^ half of 172.16 is 86.08, not 81.08 as I wrote above.