What happens when acids and bases are mixed?

Size: px

Start display at page:

Download "What happens when acids and bases are mixed?"

Henry Gallagher
5 years ago
Views:

1 c Acids and Bases ' - II,... Lesson What happens when acids and bases are mixed? KEY TERMS neutral: neither acidic nor basic neutralization: reaction between an acid and a base to produce a salt and water 109

2 LESSON 18 What happens when acids and bases are mixed? In a courtroom, a judge is not supposed to take sides. The judge is there to make sure that everything is fair for both sides. An umpire does the same thing in a baseball game. We say that people like judges and umpires are neutral. In chemistry, a liquid is neutral if it is not an acid nor a base. Take water, for example. Water is neutral. It is not an acid. It is not a base. Acids and bases have definite properties. In many ways they are opposite. What happens if you mix an acid with a base? When you mix an acid with a base, a chemical reaction takes place. The atoms from the acid and the base change the way they are linked up. New products are formed. These new products have their own properties. The properties are different from the properties of either acids or bases. What do you get? When you mix the right amounts of an acid and a base, you get a salt and water. The salt is dissolved in the water. It forms a salt solution. A salt solution is not an acid; it is not a base. It is neutral. ACID + BASE makes A SALT+ WATER The link-up of an acid and a base to form a salt and water is called neutralization [new-truh-li-zay-shun]. There are many kinds of acids. There are many kinds of bases. There are many kinds of salts. The salt you sprinkle on your food is just one kind of salt called sodium chloride. Its formula is NaCl. Different salts have different formulas. 110

3 MIXING AN ACID AND A BASE The test tube in Figure A contains twenty drops of sodium hydroxide (NaOH). One drop of phenolphthalein is added. The phenolphthalein turns deep pink. II This shows that sodium hydroxide (NaOH) is an acid, a base Figure A A different dropper is used in Figure B to add fifteen drops of hydrochloric acid (HC1) -one drop at a time. The solution stays pink. This shows that the solution is neutral, is an acid, is still a base Figure B More hydrochloric acid (HC1) is added - one drop at a time, until the pink disappears. The loss of the pink color shows that the solutionis an acid, no longer a base Figure C 111

4 The solution is tested with blue litmus paper. The blue litmus paper stays blue. This shows that the solution is not blue litmus paper an acid, a base Figure 0 The solution is tested with red litmus paper. The red litmus paper stays red. This shows that the solution is not an acid, a base Figure E CONCLUSION The mixture is, is not neutral Fill in the boxes to show what happened: SPIllSS Hydrochloric acid + Sodium hydroxide ~ Sodium chloride + Water HCl + Na(OH) NaCl NaCl in H 2 0 is an acid, a base, salt water 112

5 FILL IN THE BLANK Complete each statement using a term or terms from the list below. Write your answers in the spaces provided. Some words may be used more than once. water neutralization litmus paper an acid a base many kinds reaction a salt table neutral phenolphthalein 1. Lemon juice is an example of. Lye is an example of 2. Any substance that is not an acid or a base is said to be 3. An example of a neutral liquid is 4. The mixing of an acid and a base causes a chemical 5. If we mix the right amounts of an acid and a base, we get and 6. The chemical reaction between an acid and a base to produce a salt and water is called 7. There are of salts. 8. The most common salt is salt. 9. Salt water does not change the color of or 10. Salt water is neither nor. Salt water is MATCHING Match each term in Column A with its description in Column B. Write the correct letter in the space provided. Column A 1. HCl a) acid 2. NaOH b) water 3. H 2 O c) base Column B 4. NaCI d) indicator 5. phenolphthalein e) salt 113

6 TRUE OR FALSE In the space provided, write "true" if the sentence is true. Write 'false" if the sentence is false. 1. An acid is neutral. 2. A base is neutral. 3. Water is neutral. 4. There is only one formula for water. 5. There is only one kind of salt. 6. Salt water is neutral. 7. If you mix an acid with a base, you get only water. 8. Blue litmus paper changes to red in salt water. 9. Red litmus paper stays red in salt water. 10. Phenolphthalein turns pink in salt water. REACHING OUT When hydrochloric acid reacts with potassium hydroxide, potassium chloride is formed. The formula for hydrochloric acid is Hel. The formula for potassium hydroxide is KOH. What is the formula for water? What is the formula for potassium chloride? 114

Name: Date: Number: Acids

Name: Date: Number: Acids Acids The sour taste of the lemon juice tells us that it is an acid. Acids are special kinds of chemicals. They are common in everyday life. Some are helpful, others are harmful. There are some that are