Presentation on theme: "Introduction: Sketch the pH scale"— Presentation transcript:
1 Introduction: Sketch the pH scale Solutions and pHIntroduction: Sketch the pH scale
2 Solutions & Suspensions Water is usually part of a mixture.There are two types of mixtures:SolutionsSuspensions
3 Water is the solvent of Life! Properties of WaterUniversal SolventWater is the solvent of Life!Solute – substance dissolved in a solvent to form a solutionSolvent – fluid that dissolves solutesExample: Ice Tea – water is the solvent and tea and sugar the solutes
4 Solution Ionic compounds disperse as ions in water Evenly distributed SOLUTESubstance that is being dissolvedSOLVENTSubstance into which the solute dissolves
6 SuspensionsSubstances that don’t dissolve but separate into tiny pieces.Water keeps the pieces suspended so they don’t settle out.
7 Acids, Bases and pH H2O H+ + OH- One water molecule in 550 million naturally dissociates into a Hydrogen Ion (H+) and a Hydroxide Ion (OH-)Hydrogen Ion Hydroxide IonAcid BaseH2O H+ + OH-
8 The pH Scale Indicates the concentration of H+ ions Ranges from 0 – 14 pH of 7 is neutralpH 0 up to 7 is acid … H+pH above 7 – 14 is basic… OH-Each pH unit represents a factor of 10X change in concentrationpH 3 is 10 x 10 x 10 (1000) stronger than a pH of 6
9 Acids and BasesStrength compared using pH scaleRanges from 0 – 14Logarithmic Scale (gets 10x bigger/smaller)Acid – donates H+ when added to aqueous solutionsRanges from pH 0-6.9Base – breaks up into hydroxide (OH-) ions andanother compound when placed in an aqueoussolutionRanges from pH 7.1 – 14Distilled water is pH 7.0 or neutral. Why?H2O H OH-
10 Acids: Bases:Taste sour. Taste bitter.Give sharp stinging pain in a cut or wound. Feels slipperyTurn blue litmus paper red. Turn red litmus paper blue.Turn phenolphthalein colorless. Turn phenolphthalein pink.React with metals to produce hydrogen gas.React with carbonates or bicarbonates to produce carbon dioxide gas.
17 Making Biological Molecules and H2OCondensation ReactionH2OHydrolysis Reaction
18 PracticeWhen most people think of chemistry the first terms that come to mind are acids and bases. Many of the chemicals that people run across have some connection to acids and bases. For instance many people take medicine every day to cure heart burn. These medicines are (acids/bases). One of these comes in a blue bottle and is known as “Dr. MOM”. The common name for this is Milk Of Magnesia Another product claims that it is better for us to use because it contains calcium. So in addition to helping relieve the heartburn, it also provides us with needed calcium. This product is called Tums and its chemical name is __________________.
19 PracticeAnother product that is used all the time is Draino. Draino is a(n) (acid/base) and it has the common name of “lye” the chemical name is _____________________, and the chemical formula is ___________________. This chemical is more dangerous than the ones used for heartburn and can cause blindness or burns. (Acids/Bases) are also commonly used to produce soaps and have a (bitter/sour) taste.
20 PracticeSeltzer water and all sodas contain a very mild (acid/base) known as _____________________. This is formed by dissolving carbon dioxide in water. The chemical formula for this substance is ___________________. Vinegar is a(n) (acid/base) finds its way into our diet in ketchup and most salad dressings. The chemical name for vinegar is , the chemical formula for this substance is ___________________.
21 HomeworkKeep track of what you eat today and determine which are acids and basesBring things in from home that you would like to test for pH
22 Application Why is it important to know about pH in Biology? What happens to pH of solutions in your body when you don’t drink enough?What happens to pH of solutions in your body when you eat to many sour foods?