1. Pre-Lab Hydrated Compounds

2. Answer the following. Where appropriate answer in complete sentences. If a calculation is required show all your work. 1. Define: a)hydrated compounds b) anhydrous compounds 2. What is the purpose of the desiccator? The purpose of the desiccator is to remove water from the hydrated compound after heating, leaving behind the anhydrous compound.

3. 3. Answer the following questions about the compound CoCl 2  6 H 2 O a)What does the dot mean? The dot gives the mole ratio of the anhydrous compound to water. b) What is the mole ratio of cobalt (II) chloride to water? c)What is the molar mass of CoCl 2 ? d)What is the molar mass of 6 H 2 O? e)What is the molar mass of CoCl 2  6 H 2 O? f)What is the theoretical percentage of water in CoCl 2  6 H 2 O? water mass x 100 hydrate mass

4. 4. Sample data table. Complete this table. Show calculations under the table. 1. Mass of evaporating dish 11.49 g 2. Mass of evaporating dish + hydrated copper (II) sulfate 15.66 g a.Mass of hydrated copper (II) sulfate 3. Mass of evaporating dish + anhydrous copper (II) sulfate 14.16 g b. Mass of anhydrous copper (II) sulfate c. Mass of water d. % water in the hydrate e. Moles of anhydrous copper (II) sulfate f. Moles water g. Mole ratio h. Formula of hydrate = #2 - #1 = #3 - #1 = #2a - #3b = #3c / #2a * 100 = #3b / molar mass = #3c / molar mass = #3e/ smallest mol : #3f/ smallest mol = write formula with mole ratio #s as coefficients

5. 5. A 140.5-g sample of NiSO 4 XH 2 O is heated until no further decrease in mass. The mass of the anhydrous salt is 77.5 g. Find the coefficient for water in the formula of this hydrate of nickel (II) sulfate. Steps 1)Find g H 2 O 2)Convert anhydrous g  mol and H 2 O g  mol 3)Divide both by smallest = whole # coeff.