When acid and calcium carbonate are added together in a tube, and the CO2 is collected in a tube of limewater, what are all the signs that a chemical has taken place?
Chemical change is characterized by the formation of new substances, and the making and breaking of STRONG chemical bonds. And in practice this manifests in a colour change, a dead giveaway for chemical change, OR the evolution of a gas, OR the deposit of an insoluble precipitate.
And here we treat calcium carbonate with acid....
Certainly, the rather insoluble calcium carbonate would go up to give a clear, and colourless solution upon treatment with acid, but what else would you see?
And here we shunt the evolved gas to a solution of