Question

1 what is matter, and what does it mean when we say matter can change?

1. what makes a property physical instead of chemical?

1. what happens to the composition of a substance during a physical change?

1. why is melting ice considered a physical change?

Explanation:

1. Matter is defined as anything that has mass and occupies space. When we say matter can change, this refers to it undergoing either physical changes (altering form/state without changing composition) or chemical changes (forming new substances with different properties).
2. A property is physical if it can be observed or measured without changing the chemical composition of the substance it describes. Chemical properties require a substance to react and change its composition to be observed.
3. During a physical change, the chemical composition of the substance remains entirely unchanged; only its physical state, shape, or appearance is altered.
4. Melting ice is a physical change because the solid water (ice) only changes its state to liquid water, and the chemical composition ($H_2O$) stays the same throughout the process. No new substance is formed.

Answer:

1. Matter is anything with mass and volume. Matter changing means it undergoes physical/chemical alterations to its form or composition.
2. A physical property is observable/measurable without changing the substance's chemical makeup.
3. The composition of the substance stays exactly the same during a physical change.
4. Melting ice is a physical change because it only changes from solid to liquid water, with no change to its $H_2O$ chemical composition, and no new substance is created.