Skills for this lab: Find the molar mass of a substance (grams per mole)- add up all the elements average atomic mass using the periodic table ex: H 2 0 = H = 1 x 2 = 2 0 = 16 x 1= 16 H 2 0 is 18g/mol Convert mass to moles  divide by the molar mass How many moles in 56g of water? How many moles in 0.958g potassium cyanide?

Finding the Formula of a hydrate 1. convert grams of anhydrous compound to moles (divide by molar mass) 2. find grams of water by subtracting the original mass from the mass you get afterwards 3. convert gram s water to moles (divide by 18-the molar mass of water) 4. divide moles of water by the moles of the anhydrous compound Example problem with solution: You heat 5.56g of a hydrate (MgSO 4 XH 2 O) and the anhydrous product has a mass of 2.75, what is the formula of the hydrate? molar mass of anhydrate MgSO 4 = 120.3g/mol mass of anydrate to moles 2.75 ÷ 120.3= mol find mass of water = 2.81 mass of water to moles 2.81g ÷ 18 = 0.156mol moles water / moles anydrate / = Answer = MgSO 4 7H 2 O

14.0g of Nickel (II) Chloride is hydrated. You perform an experiment to find the formula of the hydrate. After heating the hydrated Nickel Chloride, the mass of the anhydrate goes down to 9.0g. How many grams of water was lost? What is the formula of the hydrate? Practice hydrate problem:

Substance measuredmeasurement Hydrate (CuSO 4 x H 2 0) Anhydrate CuSO 4 Water lost Moles of hydrate Moles of water Moles of water/ moles of anhydrate What is the formula of the hydrate? How close were you to the answer? (find percent error) How could this improved next time? Finding the Formula of the Hydrate Lab Write a detailed procedure for this lab List all materials Create a data table (like the one below but you can add more) Use significant figures in all calculations How to find percent error (Actual-theoretical) theoretical