Water & pH Packet #7 Chapter #2

Introduction Most abundant liquid in the world Makes up at least half of all living organisms and up to 95% of some species. 75% of earth is submerged in water Monday, December 03, 2018Monday, December 03, 2018

The Water Molecule Monday, December 03, 2018Monday, December 03, 2018

Properties of Water Density

Density H2O (l) is more dense than H2O (s) Water freezes from top downward allowing ice to form at the top Ice at top can insulate the warmer water below that layer from colder temperatures above Prevents large bodies of water from freezing solid and allowing the survival of aquatic organisms Monday, December 03, 2018Monday, December 03, 2018

Properties of Water Cohesion and Adhesion

Cohesion & Adhesion Cohesion Attraction of molecules of the same substance. The hydrogen bonding allows water to be cohesive Causes individual water molecules on the top to be drawn inward allowing for the appearance a smooth surface.

Cohesion & Adhesion Adhesion Attraction of molecules of different substances. Example of water in a graduated cylinder.

Properties of Water Specific Heat

Specific Heat Specific heat is defined as the amount of heat, measured in calories, required to raise the temperature of one gram of a substance by one Celsius degree. Water has a very high specific heat It takes a long time for water to heat up.

Major Properties of Water Density Cohesion Adhesion High Specific Heat

Other Important Water Fact(s)

Solubility Water makes an excellent solvent and makes up most solutions Any solution that contains water is called an aqueous solution.

Solubility Water is a versatile solvent due to its polarity Can form an aqueous solution. Monday, December 03, 2018Monday, December 03, 2018

Other Important Points II Hydrophilic substance Water loving Has an affinity for water Hydrophobic substance Water hating Does not have an affinity for water Monday, December 03, 2018Monday, December 03, 2018

pH

pH The pH scale will tell us how willing a compound is in giving hydrogen ions (H+) 12/3/2018 10:04:22 PM

pH—Acid & Base Reaction Bronsted-Lowry Acid A substance that donates a hydrogen ion (H+) An acidic solution has a higher concentration of H+ than pure water and have pH values below 7 Bronsted-Lowry Base A substance that accepts a hydrogen ion (H+) A basic, or alkaline solution, contain lower concentrations of H+ than pure water and have pH values above 7. Using H2O (Base) and HCl (Acid) H2O = Water HCl = Hydrochloric Acid The hydrogen in the compound HCl donates/gives it’s electron to Cl Hydrogen will have a positive charge because it is missing an electron and Chlorine will have a negative charge because it has gained an electron (These are called ions; H+ and Cl-) The oxygen atom, located in the water molecule and is electronegative, decides to give the Hydrogen ion an electron Hydrogen attaches to H2O to make H3O+ It has a positive charge because the Hydrogen ion attached missing an electron H3O+ is called the Hydronium ion In the end as a result of the Acid-Base Reaction, the end produces are H3O+ and Cl- 12/3/2018 10:04:22 PM

pH Scale 12/3/2018 10:04:22 PM

Review

Water is a polar substance Review Water & pH Properties of Water Density Cohesion Adhesion Specific Heat Solubility Mixtures Solutions Aqueous Solutions pH Acid Donates hydrogen ions Base Accepts hydrogen ions pH Scale Acids pH < 7 Neutral pH pH of 7 Bases pH >7 Water is a polar substance