Chemistry: Acids and Bases in Everyday Life
Identifying properties, pH, and safe uses of common substances
Chemistry: Acids and Bases in Everyday Life
Identifying properties, pH, and safe uses of common substances
Chemistry - Grade 6-8
- 1
Lemon juice, vinegar, and orange juice are common household substances. Explain whether these substances are acids or bases, and describe one property they often share.
Think about the taste of citrus fruits and vinegar, but remember that tasting chemicals in a lab is not safe.
Lemon juice, vinegar, and orange juice are acids. They often taste sour, and many acids can react with certain metals or with baking soda to make bubbles. - 2
Baking soda is often used in cooking and cleaning. Is baking soda acidic, basic, or neutral? Explain how you know.
Baking soda is basic. It has a pH greater than 7 when dissolved in water, and it can react with acids such as vinegar. - 3
A student tests four liquids with pH paper and records these results: Liquid A has pH 2, Liquid B has pH 7, Liquid C has pH 9, and Liquid D has pH 12. Identify each liquid as acidic, basic, or neutral.
On the pH scale, 7 is neutral, numbers below 7 are acids, and numbers above 7 are bases.
Liquid A is acidic because its pH is below 7. Liquid B is neutral because its pH is 7. Liquid C is basic because its pH is above 7. Liquid D is also basic because its pH is above 7. - 4
Toothpaste is usually slightly basic. Explain why a basic toothpaste can help protect teeth after eating acidic foods.
A basic toothpaste can help neutralize some of the acid left in the mouth after eating. This is helpful because acids can weaken tooth enamel over time. - 5
An antacid tablet is taken to help relieve an upset stomach caused by extra stomach acid. Explain how an antacid works using the words acid, base, and neutralize.
The word antacid means something that works against acid.
An antacid is a base that reacts with stomach acid. The base helps neutralize the acid, making the stomach contents less acidic. - 6
A bottle of drain cleaner has a warning label that says it is a strong base. Explain two safety precautions someone should follow when using it.
A person should wear gloves and eye protection when using a strong base. They should also avoid touching it, breathing fumes, or mixing it with other chemicals because strong bases can burn skin and eyes. - 7
Red cabbage juice can be used as an indicator. It turns reddish in acids, greenish in bases, and purplish near neutral. A student adds cabbage juice to a mystery liquid, and it turns green. What does this show about the mystery liquid?
An indicator changes color to give information about whether a substance is an acid or a base.
The green color shows that the mystery liquid is basic. Red cabbage juice changes to greenish colors when it is mixed with a base. - 8
Soap often feels slippery when mixed with water. What does this property suggest about soap, and why should students still avoid getting soap in their eyes?
The slippery feeling suggests that soap is basic. Students should still avoid getting soap in their eyes because even mild bases can irritate sensitive tissues. - 9
A recipe uses baking soda and vinegar together. The mixture bubbles and gives off a gas. Explain what type of reaction is happening in simple terms.
The bubbles are evidence that a gas is being produced.
An acid-base reaction is happening. Vinegar is an acid, baking soda is a base, and they react to form bubbles of carbon dioxide gas. - 10
A swimming pool test kit shows the pool water has a pH of 6.2. Is the pool water acidic, basic, or neutral? Explain why pool owners need to monitor pH.
Healthy pool water should usually stay close to a safe pH range, not too low or too high.
The pool water is acidic because its pH is below 7. Pool owners need to monitor pH because water that is too acidic or too basic can irritate skin and eyes and can damage pool equipment. - 11
Put these substances in order from most acidic to most basic: milk pH 6.5, lemon juice pH 2, water pH 7, soap solution pH 10.
The order from most acidic to most basic is lemon juice pH 2, milk pH 6.5, water pH 7, and soap solution pH 10. Lower pH values are more acidic, and higher pH values are more basic. - 12
A student says, "All acids are dangerous, and all bases are safe." Explain why this statement is not correct using everyday examples.
Compare weak substances used in food with strong cleaning chemicals.
The statement is not correct because some acids, such as lemon juice and vinegar, are safe in foods, while some bases, such as drain cleaner, can be very dangerous. Safety depends on the specific substance and how strong or concentrated it is.