Crushing a mineral into powder and mixing sand and gravel are both physical changes.
Physical changes are changes to the properties of substances that only affect their physical properties. The chemical properties of the substances are not altered by physical changes.
Unlike physical changes, chemical changes are changes that alter the chemical properties of substances. Most of the time, the physical properties of a substance are simultaneously altered by chemical changes.
Crushing a mineral into powder is a physical change because the chemical properties of the mineral remain intact but the physical property of being a solid has been altered to become a powder.
Mixing sand and gravel is also a physical change because the components of the mixture can be retrieved without changes to their chemical properties.
More on physical changes can be found here: https://brainly.com/question/17931044
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