Acids and Bases #2

A "traditional" base is a substance that dissolves in water to form "hydroxide" ions. These are usually ionic compounds which contain a positive metal ion, and a negative "hydroxide" ion, which is a negatively charged oxygen atom bonded to a hydrogen atom. Look what happens below. Go to the website listed below and watch the video entitled "Strong Base". There is a flash version and a .mov version. watch the following: define "base" in your own words. Also, explain what the water would be doing here. How would this differ from what happens when an acid dissolves. Be specific. Review of Acid Base Properties List the common properties of acids and bases ACIDS BASES Acids, Bases, and pH Go to the virtual lab linked below. Read the definition and instructions and then test the pH of the various substances listed. Continue until you have tested all the substances available. Fill in the table below with substance and pH. 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 11 11 12 12 13 13 14 14 15 15 16 16 17 17 18 18 Fill in the pH scale below with substances that you have NOT tested. You will need to google for this. Fill in the blanks in the text below using these words: more, greater, concentration, equal, indicators, gentler, alkaline, measuring, dangerous, dissolved, neutral, acid, base, scale An acid is a substance that releases hydrogen ions (H+) into a solution containing water. A base is a substance that releases hydroxide ions (OH-) into a solution containing water. If a base can be dissolved in water, it is also known as an alkali. The solution it forms is an alkaline solution. Acids have a reputation for being extremely dangerous, but some are safe enough to eat and use in cooking. Bases also vary, from the caustic soda used to strip paint to gentler bases found in soap. Indicators show whether a solution is acidic of basic (alkaline), with some measuring how acidic or alkaline a solution is. The concentration of hydrogen ions in a solution is measured using the pH scale. In an acidic solution, there are more hydrogen ions than hydroxide ions. In contrast, an alkaline solution has more hydroxide ions than hydrogen ions. If it has equal numbers of hydrogen and hydroxide ions, then the solution is said to be neutral. It will have a pH of 7. Acids have a pH less than 7, while bases and alkali solutions have a pH greater than 7. pH Indicators pH paper is not the only common acid base indicator. Complete the following sentences by matching up the correct pair. You may use the intnernet. Litmus paper turns red in an acid. Litmus paper turns blue in a base. Phenolphthalein turns an acid colourless and a base pink. Universal indicator has a different colour for each pH. Bromothymol blue turns acids yellow.green and bases blue. Methyl orange turns pink in an acid and yellow in a base.