G Copper (II) Sulfate forms several hydrates with the general formula CuSO4 times xH2O, where x is an integer. If the hydrate is heated, the water can be drive off leaving pure CuSO4 behind. Suppose a sample of a certain hydrate is heated until all water is removed, and its found that the mass of the sample decreases by 31%. Which hydrate is it? THat is, WHAT IS X?

Water of crystallization, X = 4.

Explanation:

Molar mass of

64 + 32 + (4x18) + x ( 1 × 2 + 16)

= 160 + 18x

Given: % water of crystallization (decrease in mass after heating) = 30%

⇒

1800x = 31 (160 + 18x)

58.0645x = 160 + 18x

(58.0645 - 18)x = 160

x = = 3.99 ≅ 4.

Water of crystallization, X = 4.

explanation: no but i do not usually comment

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.