In this case, the answer must be D.Q: Equal masses of barium carbonate and magnesium carbonate powders are mixed together. The mixture is then heated using a Bunsen burner flame until there is no further change. A gas is given off. Which statements are correct?
1) The residue left after heating reacts with aqueous hydrochloric acid to produce carbon dioxide.
2) The percentage decrease in mass after heating is 26% (to 2 significant figures).
3) The gas given off during heating relights a glowing splint.
1. The fact that some carbon dioxde is produced when the residue is treated with acid means that there is a carbonate present.
2. If 50% of the mixture is magnesium carbonate (relative mass = 84) and it decomposes to MgO (relative mass 40), then the 50% loses 44/84 x 100 % of its mass = 52.4%
so the mass loss of the 100% mixture = 26.2%( dont get this part)
How from 52.4 become 26.2?