A solution of a metal carbonate, M2CO3, was prepared by dissolving 7.46 g of the anhydrous solid in water to give 1000 cm3 of solution. 25.0 cm3 of this solution reacted with 27.0 cm3 of 0.100 mol dm-3 hydrochloric acid. Calculate the relative formula mass of M2CO3 and hence the relative atomic mass of the metal M
A solution of a metal carbonate, M2CO3, was prepared by dissolving 7.46 g of the anhydrous solid in water to give 1000 cm3 of solution. 25.0 cm3 of this solution reacted with 27.0 cm3 of 0.100 mol dm-3 hydrochloric acid. Calculate the relative formula mass of M2CO3 and hence the relative atomic mass of the metal M
how do you know the molar ratio is 2??
hydrochloric acid has only one acidic hydrogen atom that provides hydrogen ions in solution.
H+(aq) comes from HCl(aq)
These react with carbonate ions to make carbon dioxide and water, CO2 + H2O.
But to make water you need two hydrogen atoms, so you must use two mol of HCl per mol of carbonate.
2H+(aq) + CO32- --> CO2 + H2O.
All acids react with carbonates in this way (although it is actually a two stage reaction, but that's for another day)