NATURAL SCIENCES

Reactions that occur between different kinds of matter: acids and bases

EDUCATOR SECTION

Memorandum

Assignment 9:

a) Heartburn and peptic ulcers are caused by acids. An acid can be neutralised by an alkali. I will therefore drink an alkali to neutralise acids. The best household substances are milk or bicarbonate of soda, because they are alkalis that can neutralise heartburn. Also avoid the use of aspirin (acid).

b) A bee-sting is also acidic and needs to be neutralised with an alkali. I will put a bicarbonate of soda solution on the sting mark in order to neutralise the sting.

c) Since the sting is alkaline, it can be neutralised by putting an acid like vinegar/brandy on it.

d) Eat foods that contain less acids and are more alkaline or neutral. Avoid certain types of fruit, like oranges, tomatoes and fruit juices. Use a toothpaste that is more alkaline.

LEANER SECTION

Content

Activity: To discuss the effect of acids and bases on everyday phenomena [LO 2.3]

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The foodstuffs that we eat also contain many acids, which cause tooth decay. (d)

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ASSIGNMENT 9

Study the information in (a) – (d) and suggest household substances that could relieve or prevent the discomfort or effects caused by the above substances and explain why you have selected these particular substances.

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(2)

(b) __________________________________________________________________

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(2)

(c) _________________________________________________________________

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(2)

(d) __________________________________________________________________

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(3)

Assessment

Learning Outcome 2: The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

Assessment Standard 2.3: We know this when the learner interprets information by identifying key ideas in text, finding patterns in recorded data, and making inferences from information in various forms (e.g. pictures, diagrams, text).