Answer to Question #158835 in General Chemistry for Kimberly

Question

1. Calculate the percent composition by mass of ​water in the compound CaSO​4​ • 6 H​2O​ ​ [​GFM = 244].

2​.​ Calculate the percent composition by mass of ​water in the hydrate CaCl​2 ​ • 2H​2O​ .

3. ​Calculate the percent composition by mass of water​ in the hydrate ​CuSO​4​ • 5 H​2O​ ?

4. Calculate the percent composition by mass of water​ in the hydrate CaO​ ​ • 4H​2O​ [GFM = 128]

5. ​ ​What is the percent mass concentration of 45 g of a solution containing 9.0 g of KClO​3

6 ​ A single 500.0 gram serving of one sports drink contains 0.055 grams of sodium ions. Calculate the concentration of sodium ions in this sports drink, expressed as percent by mass.

Answer 1

$\omega H2O=M(H2O)/M (CaSO4*6H2O)*100$

$\omega H2O=6*18/244*100=44.26$

2.

$\omega H2O=2*18/147*100=24.49$

3.

$\omega H2O=5*18/250*100=36$

4.

$\omega H2O=4*18/128*100=56.25$

5.

$\omega KClO3=m KClO3/m*100 = 9/45 * 100=20$

6.

$\omega K+=m(K+)/m*100=0.055/500*100=0.011$