Is the reaction between corn starch and vinegar a chemical reaction?

Yes, the reaction between cornstarch and vinegar is a chemical reaction. When cornstarch and vinegar are mixed together, the vinegar's acetic acid reacts with the cornstarch's amylose and amylopectin molecules to form a new substance called starch acetate. This reaction is an example of a chemical change, because the starting materials (cornstarch and vinegar) are transformed into a new substance (starch acetate) with different properties.