Which of the following choices is the most conclusive in determining whether a chemical reaction has taken place?
a change in color
a change in odor
a gas was formed
a change in the identity of the substance(s)

if different products are not created during a process, then a chemical reaction has not occurred. true or false?

chemical equations provide:
the physical state of each reactant and product.
the ratios of reactants and products.
the chemical identity of the reactants and products.
all of the above information