Reversible and irreversible changes — task. Science CBSE, Class 7 New.

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Select the correct option:

1. Ice cream melts when kept outside the freezer (Change – A). The melted ice cream is placed back in the freezer and becomes solid again (Change – B). The following statements pertain to these changes. Choose the correct one.

Process A is an irreversible change.
Both processes A and B are irreversible changes.
Both processes A and B are reversible changes.
Process B is an irreversible change.

2. A lump of candle wax is heated and melts into liquid wax (Change – A). The melted wax is then poured into a mould and allowed to cool, forming a solid candle again (Change – B). The following statements pertain to these changes. Choose the correct one.

Both processes A and B are reversible changes.
Process A is irreversible and Process B is reversible.
Both processes A and B are irreversible changes.
Process A is reversible and Process B is irreversible.

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27. Reversible and irreversible changes

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