What are the three signs that a chemical change has taken place

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

Calculate the estimated density of each ball. use the formula d = m/v where d is the density, m is the mass, and v is the volume. record your calculations in table a of your student guide. given that the density of water is 1.0 g/cm3, make a prediction about whether each ball will float in water. record your prediction in table a. what is the estimated density of the table tennis ball? record your answer to the nearest hundredth

How many moles of co2 are produced during the complete combustion of 3.6 moles of c2h6