A student investigates the thermal decomposition of basic copper carbonate, Cu2CO3(OH)2(s)\text{Cu}_2\text{CO}_3(\text{OH})_2(\text{s})Cu2CO3(OH)2(s), which decomposes to form solid copper(II) oxide, carbon dioxide gas, and water vapour.
Two separate experimental setups are prepared on high-precision analytical balances to monitor the total mass over time, ttt:
- Setup 1: Heated in an open crucible, allowing any gaseous products to escape freely into the atmosphere.
- Setup 2: Heated in a rigidly sealed, gas-tight test tube.
Which graph in the diagram below correctly represents the total mass of each reaction vessel and its contents over time?
Graph A
Graph B
Graph C
Graph D