How do we know that caramelizing sugar is a chemical change?

Calculate the number of moles of ethane in 100 grams

Can someone me with 3 and 4 plz. this is for masteries test.

The equation below shows a chemical reaction. a + b + heat —> c + d according to the law of conservation of energy, which statement is true? a. the reactants absorb heat because they have less energy than the products. b. the products release heat because they have more energy than the reactants. c. the reactants generate heat because they have more energy than the products. d. the products require heat to form because they have less energy than the reactants.