Empirical Formula of a Hydrate Lab Jan 6, 2014 Chemistry
Title: Empirical Formula of a Hydrate • The following should be in your lab NB: • Purpose: • Find the empirical formula of copper(II) sulfate hydrate by decomposition to its anhydrous form. • Materials: • hydrate, burner, balance, small test tube, ring stand, test tube holder, scoop, test tube clamp
Types of Hydrates • Efflorescent Hydrates: • Spontaneously lose water • Hygroscopic Hydrates: • Spontaneously gain water • Don’t become completely dissolved to form solutions • Deliquescent Compounds: • absorb water from atmosphere until dissolved as a solution
Hygroscopic Compound Use • Silica gel packets • Often packaged with electronics and leather goods. • Hygroscopic hydrate – removes moisture from the air
Equation • We’re using Copper(II) sulfate • What’s the formula for Copper(II) sulfate? • CuSO4 • And we’re going to add water… • So our equation looks like: • CuSO4 nH20 CuSO4 + nH2O • Your task is to determine n
How do you determine n? • What could you measure? • mass • What is empirical formula? • moles • You have a mass to moles conversion
Lab Safety • Personal Protective Equipment (PPE) Required: • Goggles • Lab Apron • When working with open flames/heat sources, assume EVERYTHING is hot! • Don’t touch with your hands/fingers. • Never leave your burner unattended! • Keep anything flammable well away from the source of the fire. • Tie back long hair • Roll up sleeves • Watch out for drapey/flowy sleeves
Lab Techniques Test Tube Evaporating dish Only use proper evaporating dish tongs Don’t put your face over the dish (you don’t want to breathe in any fumes) Remember from your lab safety training that we treat all chemicals in the lab as hazardous! • Inspect for cracks BEFORE heating • Only use proper test tube clamps • Point opening of test tube AWAY from anyone’s face • Heat gently and uniformly • Don’t hold it in just one spot over the flame. • As condensation appears, you will move it up the tube until it is all removed.