What was the product that was produced when calcium carbonate was reacted with hydrochloric acid in the experiment shown?

In Experiment II, 20 cm3 of 0.1 mol/dm3 hydrochloric acid is reacted with excess calcium carbonate. Suggest the concentration of hydrochloric used if the same volume was used for Experiment III.

A student conducted a back titration to determine the percentage by mass of calcium carbonate in an eggshell. To do this, the student first treated 0.230 g of eggshell with excess acid, using 50.0 cm3 of 0.100 mol dm–3 hydrochloric acid. The calcium carbonate present in the eggshell reacted as follows: CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l)The excess acid was then titrated using 18.75 cm3 of 0.101 mol dm–3 sodium hydroxide via the following reaction: HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)Calculate the percentage by mass of calcium carbonate present in the eggshell to 3 significant figures.

What is the gas produced when ethanoic acid reacts with calcium carbonate? Give the name, not the symbols.

For the reaction HCl + Ca CO3 -> Ca Cl2 + CO24a. Suggest 2 observations that makes you confirm a chemical reaction have taken place

How much calcium hydroxide is produced by the complete reaction of 150.0 g CaO with 50.0 g of water?