When the universal indicator was added to the water was this a physical or chemical change

It is a chemical change. the indicator reacts with the water giving a color change.

Chemical change, because its not a change in structure, just a change with mixing of chemicals.
Hope this helps~!
~{Dunsforhands}

Mg-26 and mg-24 are pair of isotopes. isotopes are defined as atoms of the same element having same atomic number but different mass number. i hope that was .

Idont really know sorry