Y10 Science 16/02/2016
ACIDS AND INDICATORS
2 weeks
Material World Achievement Objectives:
Properties and changes of matter:
 Investigate the chemical and physical properties of different groups of substances, for example acids and bases, fuels and metals.
 Distinguish between pure substances and mixtures and between elements and compounds.
The structure of matter:
 Describe the structure of the atoms of different elements.
 Distinguish between an element and a compound, and a pure substance and a mixture at particle level.
Chemistry and society:
 Link the properties of different groups of substances to the way they are used in society or occur in nature.
Focusing questions?
 What is an acid?
 How are acids detected?
 What is pH a measure of?
 How is acid rain formed?
 What sorts of substances react with acids?
 How is chemical equation written?
Key competencies focus:
All key competencies are incorporated into this unit of work, however, in this unit there is particular emphasis on:
 Using language, symbols, and texts.
Assessment focus:
 Nature of science: Investigating in science – Acids in food
 Written test
Literacy focus- keywords:
Key words/terms: formula, compound, reactant, product, equation, acid, base, carbonate, neutral, neutralise, indicator, litmus, Universal Indicator,
hydrochloric acid, sulphuric acid, sodium hydroxide, sodium bicarbonate, calcium carbonate, limewater, pop test, carbon dioxide, hydrogen.
Note: NOS = Nature of Science text NMS = New Millennium Science text KISS = Kiwi Integrated Science text WB = Science 10 workbook
Learning Experiences
Resources
1. Acids and indicators
 Make a list of common acids and bases in school (including formulae) and at
home (simple formulae only).
 Test a variety of lab and consumer/food acids and bases with litmus paper and
Universal Indicator solution.
NOS 2 p30-35
WB Prac 15A1 p134
WB Prac 15A3 p136
WB Prac 15A4 p137
NMS 2 p44-45 (Acids)
Nature of
science focus
Investigating
Y10 Science 16/02/2016
Learning Experiences
Resources
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
KISS Bk 3 p32
NMS 2 p42-43 (Neutral)
KISS Bk3 pg42
WB Acid or base, Understanding pH, pH
perfect p23 - 25
WB Prac 15A5 p137
KISS Bk3 pg50
2.




Copy scale and colours of Universal Indicator.
Taste some tartaric acid.
Plant Indicators
Boil up dark red or blue flowers, red cabbage, beetroot or a dark fleshed fruit.
Soak filter paper in pigment and dry overnight.
Keep some solution and test with acid and base.
Next day, put a drop of acid on a small piece of plant indicator paper and do the
same with base. Stick a bit of original indicator paper in book with the two other
bits.
3. Reactions of acids 1
 Acid + metal e.g Mg + HCl
 React and collect gas and carry out ‘pop test’.
 Record qualitative observations first.
 Write word equation, particle picture equation and symbol equation.
 General equation: ACID + METAL = SALT + HYDROGEN
 Write equations for pop test also.
 Hydrogen + oxygen = water
4. Reactions of acids 2
 Acid + carbonate e.g Sulfuric acid + calcium carbonate (marble chips).
 Bubble gas through limewater.
 Record qualitative observations first.
 Write word equation, particle picture equation and symbol equation.
 Write equation for pop test.
 General equation: ACID + CARBONATE = SALT+WATER+CARBON DIOXIDE.
 Try juicing a lemon and tasting, then add baking soda bit by bit until fizzing stops.
Taste again. It should be less sour. Shows that carbonates also neutralise acids.
5. Reactions of acids 3 (two periods needed)
 Acid + base e.g HCl + NaOH
 Practical: React equal volumes of 2M solutions of NaOH and HCl and record
temp of each solution and temp change upon mixing (temp increases which
proves chemical reaction has occurred).
 Pour solution into evaporating basin and boil off liquid – salt should be left.
 Practical: Titrate 0.1M solutions of ethanoic acid and ammonia solution. Add
Universal indicator to ethanoic acid first. Add ammonia bit by bit until indicator
changes colour from red to green. Add more ammonia until blue.
Nature of
science focus
Investigating
Communicating
KISS Bk 3 p34-36
Investigating
Communicating
KISS Bk 3 p34-36
Freshly prepared limewater (make sure it is
prepared at least 24hrs earlier to allow solid to
settle)
WB Prac 15B1 p138
WB Chemical detective p31
WB Baking soda p29
Investigating
Communicating
NOS 2 p36-39
NMS p46-47 (Bases)
KISS Bk3 pg40
WB Prac 15A2 p135
WB Prac 15B2 p139
WB Tummy trouble p32
WB Acid attack p30
Investigating
Communicating
Y10 Science 16/02/2016
Learning Experiences
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6.

Proves that ammonia (a base) neutralizes the acid.
Write word equation, particle picture equation and symbol equation.
General equation: ACID + BASE = SALT + WATER
Application of knowledge of acids and bases: Acid rain
Teacher demo: Make a gas jar full of oxygen leaving a small quantity of water.
Add a squirt of Universal Indicator. Burn some sulphur using a deflagrating
spoon. Watch U.I change colour. Add spatulas of sodium carbonate (in lieu of
lime as works quicker) to show how acid is neutralised.
 Discuss acid rain formation both natural (volcanoes) and man-made (factories).
 Discuss how in Scandinavia lakes were topdressed with lime to reduce acidity.
7. Summary of reactions
 Write word and symbol equations (for those who can cope) for a variety of
reactions.
 Rules: Hydrochloric acid produces chloride salts, sulphuric acid produces
sulfates, nitric produces nitrates etc
8. Acids in food investigation assessment
 Compare the effect of different food/drinks on a piece of Mg.
Resources
Nature of
science focus
KISS Bk 3 p38
Participating &
contributing
WB Find the family p28
WB Household cleaners p27
WB Common.. but dangerous p26
Reaction Mix and Match
Formula Mix and Match
Investigation: Acids in food
Post-test & Unit test
Investigating
Participating &
contributing