measure how acidic or basic a substance is. It goes from .
e. A substance with a pH of 7 is described as a
substance. f. A is a method used to find
out how much acid is needed to neutralise a base.
g. A neutralisation reaction is an . This means it is a reaction
that gives out energy.
h. An acid and a base react to give and
. i. A is a chemical compound,
formed when the hydrogen part of an acid is replaced by a
. j. The acid in our stomach is called . It is needed to help with acid can cause
. Excess stomach .
2. Name two acidic, two basic and two neutral substances.
3. Some foods, such as beetroot, are preserved in vinegar. Explain why the vinegar makes the vegetable last longer.
. is used to show whether a
4. Explain what an indicator is. What are the limitations of testing a substance with litmus indicator?
5. Draw the pH scale and add as many examples as you can for each pH. You may need to research additional examples online.
6. Calculate which solution is more concentrated:
Solution A, which has 22 g of alkali dissolved in 250 cm3 of water.
Solution B, which has 10 g of the same alkali in 500 cm3 of water.
Show your calculations.
7. Give an explanation for each of the following: a. A mixture of baking soda and vinegar fizz when combined.
b. Rubbing vinegar on a wasp sting reduces the irritation.
c. Taking an indigestion remedy relieves the symptoms of heartburn.
8. The soil in Claire’s garden has a pH 4.5. Claire really wants to grow an apple tree, which needs a pH of approximately 5.0–6.8 to grow. How can Claire adjust the pH of the soil to ensure that the tree grows? Research other plants she can grow in her garden.
9. Draw the hazard symbol you would see on concentrated acids and bases. Explain what this symbol means.
10. Acid rain can cause the pH of lakes to drop to dangerous levels. How could you deal with this problem?
