pH Ionization and Hydrogen Bonding

pH pH is the concentration of hydrogen ions in a solution

Strong Acid and Base HCl – hydrochloric acid Strong acid H+ loses electron to Cl- Solution would have a HIGH concentration of H+ ions NaOH – sodium hydroxide Strong base Na+ loses electron to OH- Solution would have a HIGH concentration of OH- ions

Buffers Weak acids/bases that react with strong acids or bases to have a gradual shift in the pH scale Ex: Milk calming stomach acid

Why is water neutral? The molecule of H 2 O separates into H+ loses electron to OH- Equal parts of each ion H 2 O has a neutral pH of 7

pH scale

Demonstration Are the pieces of paper without water more attracted to each other? Why are the pieces of paper with water easier to stick together? What is holding the papers together? Water is a polar molecule Partial negative pole and partial positive side

Hydrogen bonding Due to partial positive and partial negative poles on the water molecule, other water molecules are attracted to each causing a hydrogen bond Not as strong as covalent or ionic bonding

Hydrogen Bond 1/animations/hydrogenbonds.html 1/animations/hydrogenbonds.html What are the other unique properties of water?

Cohesion

Cohesion – Surface Tension

Adhesion

Adhesion - Capillary Action How water moves up plants Plant tubes (xylem) are made of cellulose which is polar Water molecules are attracted to the sides of thin tubes of xylem What do you think will happen to the daisies?

Capillary Action How water moves up plants Water molecules are attracted to the sides of thin tubes plant walls This is also why water moves up a straw without you doing anything!

Activity! Drops of water on a penny What properties of water are shown in this experiment?