Starter quiz
- When a substance changes from a solid to a liquid, it is called ______.
- 'melting' ✓
- Which of the following is an example of a chemical change?
- Ice melting
- Water boiling
- Iron rusting ✓
- Sugar dissolving
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- A ______ change is one that does not produce new substances and can often be reversed.
- 'physical' ✓
- Which of the following represents a physical change?
- Burning wood
- Baking a cake
- Dissolving sugar in water ✓
- Digesting food
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- What is the main difference between a physical change and a chemical change?
- Physical changes produce new substances, chemical changes do not.
- Chemical changes produce new substances, physical changes do not. ✓
- Physical changes are irreversible, chemical changes are reversible.
- Chemical changes involve only a change in state.
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- An ______ is a substance made of one type of atom.
- 'element' ✓
Exit quiz
- What is a chemical reaction?
- A process where atoms remain unchanged
- A process where atoms are rearranged to form new substances ✓
- A physical change
- A temporary change
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Where are products found in a chemical equation?- On the left-hand side
- On the right-hand side ✓
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- What do bubbles indicate in a chemical reaction?
- A liquid is evaporating
- A gas is being produced ✓
- A solid is dissolving
- A substance is melting
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- Which observation(s) always indicate a chemical reaction has taken place?
- Precipitation ✓
- Dissolving
- Bubbling
- Melting
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- ______ are the elements or compounds before a reaction takes place.
- 'reactants' ✓
- Most chemical reactions can be classed as ______ reactions, because the reaction occurs in one direction only (where the reactants are converted into the products).
- 'irreversible' ✓
Worksheet
Presentation
Video
Lesson Details
Key learning points
- Characteristics of chemical reactions include changes in colour, bubbling, or a change of temperature.
- Bubbles appear when a gas is produced in a chemical reaction.
- In a chemical reaction, atoms rearrange themselves to form new substances.
- Generally, chemical reactions are irreversible.
Common misconception
Pupils do not understand chemical reactions as changes, they considered them to be ‘events’. They focus on observable features e.g. colour change rather than formation of a new substance.
Use questioning to encourage pupils to make links between their observations as evidence that a new substance is formed when substances undergo chemical reactions.
Keywords
Chemical reaction - when atoms are rearranged to make new products and changes can be observed e.g. bubbles of gas forming.
Irreversible reaction - occurs in one direction only where the reactants are converted into the products.
Reactants - elements or compounds before a reaction takes place. Reactants are found on the left hand side of a chemical equation.
Products - elements or compounds that are formed after a reaction has taken place. Products are found on the right hand side of a chemical equation.