Why is it important to do further investigations to determine if a chemical change really occurred?

A48 g piece of ice at 0.0 ∘c is added to a sample of water at 7.4 ∘c. all of the ice melts and the temperature of the water decreases to 0.0 ∘c. how many grams of water were in the sample?

Silver tarnishes as silver metal reacts with hydrogen sulfide, h2s, in the air. in this reaction, dark silver sulfide, au2s, covers the surface of silver. when silver is polished, this coating of silver sulfide can be removed from the surface. this makes the silver shiny again. enter the coefficients that balance the tarnishing reaction equation. (type 1 for no coefficient.)

How many moles of sulfur dioxide are produced when 4.38 moles of oxygen completely react with iron (iv) sulfide