Can a physical change, change what a substance is? explain your answer by giving an example.

Physical changes are changes affecting the form of a chemical substance, but not its chemical composition. Physical changes are used to separate mixtures into their component compounds, but can not usually be used to separate compounds into chemical elements or simpler compounds.

Example: Ice melting involves a change from a solid to a liquid and the substances maintain the properties of water because the molecules never change.

29.1-12=17.1the answer is this one

Abbreviated as mg-25.