CLASS 6 · LEARNING KNOWLEDGE
Physical and chemical changes – basic principles
How it works
Physical changes affect the state, form, or distribution of a substance without new substances being formed. Examples are melting, evaporating, crushing, or dissolving. Chemical changes lead to the formation of new substances with different properties, for example when burning or rusting. To distinguish between them, one mainly considers whether new substances are formed and which substance properties are present before and after the process.
Note
Physical changes change only the state, form, or distribution of a substance, but not its chemical composition. Chemical changes lead to the formation of new substances with new properties.
Physical changes change only the state, form, or distribution of a substance, but not its chemical composition. Chemical changes lead to the formation of new substances with new properties.
An example
Ice melts into water. Is that a physical or chemical change?
Melting ice is a physical change, because only the state of aggregation changes, but no new substance is formed.
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50 Exercises
To the learning unit →Own explanation and own practice exercises by AmyMath. Subject reference framework: Chemistry. The topic assignment may vary by federal state.