Acids, Bases and the Fizz: teacher key

Mixing and Reactions, grade 5 edition, written for 5th grade. Vinegar and baking soda fizz because an acid meets a base. Read how bubbles form, how scientists sort acids from bases, and why oil and water will not blend.

Read the book. Print this page for the key.

Questions and answers

1. What makes the bubbles when baking soda meets an acid?
   • Carbon dioxide gas (answer)
   • Salt
   • Oil
2. On the pH scale, which number is neutral?
   • Zero
   • Seven (answer)
   • Fourteen
3. A liquid has a pH of 3. What kind of liquid is it?
   • A base
   • Neutral
   • An acid (answer)
4. Red cabbage juice is a natural indicator. What does it do?
   • Shows one color in an acid and another in a base (answer)
   • Makes bubbles in vinegar
   • Turns iron to rust
5. In an emulsion, tiny drops of one liquid are what?
   • Burned away
   • Spread through the other (answer)
   • Turned to gas
6. What is amylase?
   • A kind of oil
   • A gas
   • An enzyme that helps us digest carbohydrates (answer)

Words

• acid: sour kind
• indicator: acid tester
• emulsion: drops in liquid
• enzymes: reaction speeders
• neutral: in the middle