Water, Water, Everywhere

Formula: H2O

Bond within H2O: Covalent bond (shared electrons)

The electrons in water are unevenly shared, which results in water being a polar molecule

Hydrogen-bonding between water molecules give water very special properties!

Density of Water (liquid) is larger than the Density of Ice (solid) because ice needs more space than water

This means that: Ice floats in Water! This creates an insulating layer of ice allowing sea life to survive!

Water is called the Universal Solvent! This means that most things will dissolve in water What things do not dissolve in water???

“Like dissolves Like” Polar solutes dissolve in polar solvents Ionic compounds are considered extremely polar Nonpolar solutes dissolve in nonpolar solvents Dry cleaners use nonpolar solvents to remove oil and grease stains.

Salt dissolves in water by breaking apart its ions This is called Dissociation

Dissociation The process in which positive and negative ions of an ionic solid mix with the solvent to form a solution

More Definitions! Electrolytes – Compounds that produce solutions of ions in water. Solutions containing electrolytes conduct electricity Could not live without Example: Salt (NaCl)

Nonelectrolytes – Substances that form no ions in water. Do not conduct electricity Examples: Fats and sugars

Solute = the “little”____ = table salt

Solvent = the “big”________ = water

Salt Water Solution_____:

Water Related Questions 1 Swimmers find that they can float more easily in the ocean than in a freshwater pond. The most likely reason for this phenomenon is that the — A viscosity of pond water is greater than that of ocean water B density of ocean water is higher than that of pond water C temperature of pond water is lower than that of ocean water D mass of ocean water is greater than that of pond water

2 Which factor makes water an effective solvent? A The presence of molecular oxygen B Its lack of covalent bonds C The polar nature of its molecules D Its abundance on Earth’s surface

3 Fish survive through severe winters because of the property of water that allows water to — A form chemical bonds as it freezes, raising the water temperature below the ice B increase in density while it freezes, dissolving more oxygen from the air C expand when it freezes, creating a floating and insulating layer of ice D precipitate vital nutrients when it freezes, increasing the food supply

4 The diagram shows water molecules and ions from a NaCl crystal 4 The diagram shows water molecules and ions from a NaCl crystal. What is the reason that each water molecule is arranged so that the oxygen part of the molecule faces a sodium ion? A The oxygen in a water molecule contains a partial negative charge B Gravity rotates the oxygen atoms to face the more massive sodium atoms C Hydrogen atoms create repulsive forces with chloride ions D Oxygen atoms form covalent bonds with sodium ions

The End!