An aqueous solution is 15.0% by mass of copper(ii) sulfate pentahydrate, cuso4∙5h2o. what
is the molarity of cuso4 in this solution at 20°c? the density of this solution at 20°c is1.167
g/ml(molecular weight of cuso4∙5h2o = 249.5, molecular weight of cuso4 = 159.5)

0.702 mol / dm³.

Consider a 1,000 mL sample of this solution. Mass of the sample:

.

The mass ratio of copper(II) sulfate pentahydrate in this sample is 15 %. In other words, among that 1,167 grams of the solution is .

Number of moles of in that of the hydrate:

.

Concentration of the hydrate:

.

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

i think its 100.

hope this !