1.

What are indicators used for in science?

To show which things are acids and which are alkalis.

2.

What colour does litmus turn in acid?

Red (pink).

3.

What can you use to crush up a plant and get its colour out?

A pestle and mortar

4.

Why is Universal Indicator often more useful than other indicators?

Because it can tell you how strong or weak an acid or alkali is.

5.

What is the pH of a neutral solution?

7.

6.

Sodium hydroxide has a pH of 14. What does this tell you about sodium hydroxide?

It is a strong alkali.

7.

What would be the pH of a strongly acidic solution?

1.

8.

How does acid affect limestone?

It reacts (fizzes) wearing away (dissolving) the rock

9.

What is the missing word?

Alkali.

Acid + ________  = neutral solution.

10.

What causes indigestion?

Too much acid in the stomach.

11.

How do indigestion tablets work?

They neutralise the excess acid in the stomach

12.

Why is toothpaste usually slightly alkaline?

So it can neutralise the acids that cause tooth decay.

13.

How can farmers change the pH of acidic soil?

By adding lime (an alkali).

14.

How would you test the pH of some soil?

Add distilled water filter, then add Universal Indicator solution to the filtrate.

15.

Wasp and ant stings are caused by acidic chemicals. If a dock leaf can be used to neutralise a wasp sting, what sort of chemical does a dock leaf contain?

An alkali.              

Baking powder is a weak alkaline. What colour would it turn Universal Indicator?

Turquoise

17.

Lemon juice turns Universal Indicator solution yellow. What pH value does it have?

5-6