Question

physical and chemical changes - 7.6c
what other changes do you see happening around you?
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Explanation:

To answer this, we can list common physical and chemical changes:

Physical Changes (no new substance, just form/state change):

• Melting ice: Ice (solid $\ce{H2O}$) becomes liquid water.
• Freezing water: Liquid water turns to solid ice.
• Evaporating water: Liquid water becomes water vapor (gas).
• Crushing a can: Changes shape, but still aluminum.
• Mixing salt and water: Salt dissolves (physical, reversible by evaporation).

Chemical Changes (new substance forms, often irreversible):

• Burning wood: Wood (cellulose) reacts with $\ce{O2}$ to form $\ce{CO2}$, ash, etc.
• Rusting iron: Iron ($\ce{Fe}$) reacts with $\ce{O2}$ and $\ce{H2O}$ to form rust ($\ce{Fe2O3}$).
• Cooking an egg: Proteins in the egg denature (chemical change, new structure).
• Digesting food: Enzymes break down food into new substances (e.g., starch → glucose).

For example, you could write: "I see physical changes like ice melting into water (state change) and chemical changes like iron nails rusting (new substance, rust, forms) or wood burning in a fire (produces ash and smoke)."

This explains both types of changes with real - world examples.

Answer:

To answer this, we can list common physical and chemical changes:

Physical Changes (no new substance, just form/state change):

• Melting ice: Ice (solid $\ce{H2O}$) becomes liquid water.
• Freezing water: Liquid water turns to solid ice.
• Evaporating water: Liquid water becomes water vapor (gas).
• Crushing a can: Changes shape, but still aluminum.
• Mixing salt and water: Salt dissolves (physical, reversible by evaporation).

Chemical Changes (new substance forms, often irreversible):

• Burning wood: Wood (cellulose) reacts with $\ce{O2}$ to form $\ce{CO2}$, ash, etc.
• Rusting iron: Iron ($\ce{Fe}$) reacts with $\ce{O2}$ and $\ce{H2O}$ to form rust ($\ce{Fe2O3}$).
• Cooking an egg: Proteins in the egg denature (chemical change, new structure).
• Digesting food: Enzymes break down food into new substances (e.g., starch → glucose).

For example, you could write: "I see physical changes like ice melting into water (state change) and chemical changes like iron nails rusting (new substance, rust, forms) or wood burning in a fire (produces ash and smoke)."

This explains both types of changes with real - world examples.