Oxygen and magnesium come together in a chemical reaction to form this compound. After it burns, it forms a white powder of the magnesium oxide. Magnesium gives up two electrons to oxygen atoms to form this powdery product. This is an exothermic reaction.
CaCO3 is the reactant in excess. The amount of CaCO3 remaining is 11.5 g . ... Hydrochloric acid and calcium chloride. 2 mol HCl1 CaCl2. Determine the mass of CaCO3 that reacted with the limiting reactant HCl .