Properties of Water Lab
Introduction: Water is a simple molecule, yet itʼs most vital to all living things. It has the highest specific heat of everyday substances. Unique properties of water enable it to carry out functions that no other substances can. In a neutral aqueous solution, five molecules of water are bonded together by weak hydrogen bonds. Furthermore, due to the electronegativity of oxygen, water is a polar molecule. Due to its polarity, water is classified as the universal solvent. You will investigate the life-sustaining properties of water throughout this lab.
Part One: Polarity
Label the diagram of water below. Make sure you label the oxygen, hydrogen atoms as well as the partial charges which creates waterʼs polarity.
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What causes polarity?
Why does polarity allow water to be such a good solvent?
Measure 10 grams of NaCl and add this to a cup of 100 ml water.
Stir the salt to dissolve. Record how long it takes to dissolve all of the salt. __________
Which is the solute? _______________________
Which is the solvent? _______________________
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Add oil to a cup of water.
Does the oil mix with water? _______
Is oil considered a hydrophobic or hydrophilic substance? Why? __________________________________
Part Two: Hydrogen Bonding, Expansion on Freezing
Water tends to “hang-out” in groups of five molecules. This is due to hydrogen bonding. Label the 4 hydrogen bonds shown in the below diagram. Explain what a hydrogen bond is (as compared to covalent and ionic bonds). hydrogen ionic covalent
Water expands when it freezes. Describe a test that you could complete at home to prove water expands as it freezes.
Part Three: Adhesion, Cohesion, Surface Tension
Adhesion is the ability of water to stick to others substances. For example, water can stick to the side of a swimming pool. Cohesion is the ability of water molecules to stick to