Answer:
1. temperature color
3. density of the products compared to the reactants
Step-by-step explanation:
In a chemical reaction, there is a rearregement in the atoms breaking and bonding different bonds producing a change in energy that means a change in temperature.
A chemical reaction can be detected by change in color in reactions as titrations, for example, where phenolphthalein is pink in basic pH and non-color in acid pH.
For the law of conservation of matter, overall mass of the products is the same to the mass of the reactants.
As in a chemical reaction you have a rearregement in the atoms, it is possible that this rearregement produce a better organization in the atoms increasing density or a poor organization decreasing density.
I hope it helps!