Presentation on theme: "PH This is a rough measure of the acidity of a solution. The "p" stands for "potenz" (this means the potential to be) and the "H" stands for Hydrogen."— Presentation transcript:
pH This is a rough measure of the acidity of a solution. The "p" stands for "potenz" (this means the potential to be) and the "H" stands for Hydrogen. So you must write pH with a lower case (little) p and an upper case (capital) H. Writing PH would mean a public house! Writing Ph would mean philosophy as in PhD = a Dr. of Philosophy.
The acidity of a water sample is measured on a pH scale. This scale ranges from 0 (maximum acidity) to 14 (maximum alkalinity). The middle of the scale, 7, represents the neutral point. The acidity increases from neutral toward 0. Because the scale is logarithmic, a difference of one pH unit represents a tenfold change. For example, the acidity of a sample with a pH of 5 is ten times greater than that of a sample with a pH of 6. A difference of 2 units, from 6 to 4, would mean that the acidity is one hundred times greater, and so on. Normal rain has a pH of 5.6 – slightly acidic because of the carbon dioxide picked up in the earth's atmosphere by the rain. Click Click here
The gentleman who invented the pH scale wanted to measure how acid his beer was. As you know you have to use yeast to make beer or wine, and you also know that yeast uses enzymes. Enzymes only work if the pH is right. What he discovered was that acids and alkalis make the colors in plants change. Try grinding up some red cabbage or a beetroot. You will get a red or blue liquid. You can make the liquid change color by adding acids or alkalis. All that happens is that the color of the plant dye depends upon the concentration of Hydrogen ions.
Water is neutral – has a total charge of 0 O 2- H +1 O 2- H +1 O 2- H +1 Acids have an extra and are unbalanced H +1 Bases are missing a and are unbalanced – they are left with OH H +1
For example, hydrochloric acid (HCl) dissolves in water as follows: HCl in H 2 O gives you H+ + Cl- Bases are substances that dissolve in water to release hydroxide ions (OH-) into solution. For example, a typical base is sodium hydroxide (NaOH): NaOH in H 2 O gives you Na+ + OH- The neutralization reaction of an acid with a base will always produce water and a salt, as shown below: Acid + Base = Water + Salt HCl + NaOH = H 2 O + NaCl HBr + KOH = H 2 O + KBr
Ammonia in Water = NH 3 +H 2 0 = NH 4 + OH Lime water = CaO + H 2 0 = Ca(OH) 2 Bleach + water = NaOCl + H 2 0 = NaCl + (OH) 2 Milk does not have a chemical formula. It is a mixture of about 100 different things that DO have chemical formulas. The number one ingredient in milk is water (88%) with the formula H2O. After that there is the sugar Lactose (about 4.6%) with formula C12H22O11, the major protein Casein (3.2%) with a very complex formula, and Fat of various types of milk fat (3.4%).
pH Down – Sulfuric acid - lowers the pH number making it less alkaline (base) pH Up – Sodium Carbonate & Water - raises the pH number making it less acidic Alkaline water is unsuitable for egg laying fish, promotes green algae and can be harmful to certain live plants. Acid water is harmful to live bearing fish, promotes brown algae and can be harmful to plants and animals. Na 2 CO 3 H 2 O
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