1. Draft Changing substances: hierarchy of knowledge Chemical & physical
How is an expert’s understanding of the subject organised?
Big idea Reactions rearrange matter
During a chemical reaction, bonds are broken and the atoms of the reacting substances rearrange to form new bonds. The products have different properties to the reactants. In physical changes the molecules do not change, but their positions and their motion may.
Unit concept
Chemical & physical
Unit concept
pH scale
Unit concept
Neutralisation
Sub-concepts
Chemical change, physical change
Sub-concepts
Acid, alkali
Sub-concepts
Base
Facts
Neutral substances have pH 7
What scientific reasoning, maths, literacy and problem solving skills are developed?
Skill area
Develop hypotheses
Identify and record key observations and suggest a hypothesis
Skill area
Consider risks
Identify ways of reducing hazards and risks when carrying out an investigation
Skill area
Engineer solutions
Design a solution to meet criteria
Draft
Note: the content is in draft form and may change when published © Mastery Science, 2018

2. I can use my knowledge to
Changing substances unit
Chemical engineer
Activate
I understand earlier concepts
Acquire
I can make sense of the idea that ..
Apply
In unfamiliar situations, I can use the concept to ..
Analyse
I can use higher order thinking to ..
Chemical & physical
Material properties
A chemical change makes a new substance. It is identified by changes in appearance, energy, mass, or chemical tests
Use observations to identify a chemical or physical change
Suggest a hypothesis about mass in a chemical change
Evaluate an experimental method in terms of the hazards and risks
pH scale
Material properties
The pH scale measures how acidic or alkaline a solution is. Indicators are substances whose colour depends on pH
Identify the best indicator to distinguish solutions of different pH, from data
Deduce the hazard of a substance from data about concentration and pH
Neutralisa- tion
pH scale
Neutralisation is a chemical change when acid and alkali (or base) react to produce neutral substances
Work out how to neutralise solutions based on pH
Develop a method to design and test a safe, effective antacid
Act
I can use my knowledge to
Design and build a system to reduce ocean acidification
Note: the content is in draft form and may change when published © Mastery Science, 2018

3. (AQA Trilogy combined science)
Changing substances: national curriculum
Which parts of KS3 are covered?
AQA KS3 syllabus: Acids and alkalis
Which parts of GCSE are covered?
(AQA Trilogy combined science)
pH scale
The pH scale and neutralisation
Develop hypotheses
WS 2.1 Use scientific theories and explanations to develop hypotheses
Consider risks
WS 1.5 Evaluate risks in practical science
WS 2.4 Identify risks and hazards
What practical skills can be developed?
Apparatus and techniques
AT.3.C
AT.6.C
What resources are there to teach this unit?
Below are some ideas. Visit to see more teaching & assessment resources, including:
Advanced planners with teaching ideas for Acquire
Mastery Practice Books to practise Apply
Diagnostic and summative assessments for Acquire, Apply and Analyse
Teaching
ideas
Analyse Students use information about the hazards and pH of a range of acidic and alkaline substances to choose a suitable chemical to use as an antacid. They then test their ideas and measure effectiveness by using them to neutralise acid, modelling what happens in the stomach
Act Seawater acidity caused by increasing concentrations of carbon dioxide in the atmosphere has negative effects on sea life. In this activity, teams use plastic tubing, bottles and balloons to design and build a system that blows bubbles of air to reduce the amount of dissolved carbon dioxide in water, changing the water from acidic to neutral
Note: the content is in draft form and may change when published © Mastery Science, 2018