Lesson 7 - Acids , Bases, and Salts.pptx

Lesson 7 - Acids , Bases, and Salts.pptx for Grade Seven Students

1. ACIDS, BASES, and SALTS Investigate properties of acidic and basic mixtures using natural indicators Discuss the uses of acids and bases in our daily lives

2. What is the effect of an Acidic Mixture on Iron? Materials: 3 pieces of small iron nails 1 cup white vinegar 100 mL beaker 2 droppers Procedure: Make sure that all the iron nails and the beakers are free from moisture. Put one piece of iron nail in each bottle/beaker. Add 2-3 drops of vinegar on top of the iron nail in the beaker. Place the setup where you can observe changes in the iron for three days. Prepare a table for your observations. Analysis: Describe completely what happened to each sample. Explain your answer.

3. Indicators – are substances whose colors are affected by acids and bases. An example of an indicator is the litmus paper. Acids change a blue litmus paper to red. Bases change a red litmus paper to blue. Salts do not affect the indicators. More common examples of indicators are thymol blue and methyl orange.

4. Acids – are compounds that contain hydrogen, which when dissolved in water breaks loose as a hydrogen ion. The presence of hydrogen ion gives acids the following characteristics: Acids’ most distinct characteristic is their taste. They have a sour taste similar to the taste of citrus fruits. Do not taste to test the presence of acid. Some can produce painful burns. In industries, many acids are very strong. Therefore, they should be handled with care.

5. Acids change the color of certain substances like litmus paper. It changes from blue to red when placed in an acid solution. Acids are electrolytes. They produce hydrogen ions which can conduct electricity when dissolved in water. Acids neutralize bases, forming water and salts from the reaction.

6. SOME COMMON ACIDS Acid Formula May be found in: Acetic CH3COOH Vinegar Carbonic H2CO3 Soft drinks Ascorbic C5H9O5COOH Citrus fruits Formic HCOOH Red ants Lactic CH3CHOHCOOH Sour milk Nitric HNO3 Cleaning solutions Phosphoric H3PO4 Detergents/Fertilizers Hydrochloric HCI Muriatic acid

7. Sulfuric acid – is widely used for the manufacture of plastics, detergents, batteries, and metals. Hydrochloric acid – is found in the stomach to aid digestion. Nitric acid – is used in the manufacture of explosives, rubber, dyes, and pharmaceuticals. Phosphoric acid – used in manufacture of fertilizers, animal feeds, detergents, and ceramics. Acetic acid – used in manufacture of plastics and food supplements such as lysine and fungicide

8. CLASSIFICATION OF ACIDS Binary acid – is an acid that contains only two different elements: hydrogen and one of the nonmetals. Oxyacids – are composed of hydrogen, oxygen, and a nonmetal. Acids can have negative effects. Acid rain causes much damage to buildings, statues, iron works, and trees.

9. Bases – are called alkaline substances and they have their own characteristics when dissolved in water. Solutions of bases have a bitter taste. Remember that tasting bases can be hazardous since some are corrosive. Solutions of bases feel slippery on the skin. Bases change the color of substances. Red litmus turns blue when placed in a solution containing a base. Bases neutralize acids, forming water and salts from the reaction.

10. Safety in Handling Acids and Bases

11. Safety in Handling Acids and Bases Acids and bases with high concentrations can cause serious burns if not properly handled. (Ex. Muriatic Acid ) Q. How can you be safe in handling acids and bases? Read the product labels of common acids and bases properly for safety.

12. Labels Contain Signal Words Caution – appears on products that are less harmful to you. Warning – means a product has more serious effects than the one with a “Caution” label. Danger – means a product is a poisonous and should be used with extreme care.

13. Sulfuric acid – is widely used for the manufacture of plastics, detergents, batteries, and metals. Hydrochloric acid – is found in the stomach to aid digestion. Nitric acid – is used in the manufacture of explosives, rubber, dyes, and pharmaceuticals. Phosphoric acid – used in manufacture of fertilizers, animal feeds, detergents, and ceramics. Acetic acid – used in manufacture of plastics and food supplements such as lysine and fungicide