The law of conservation of mass applies to every reaction. In this case, you start with 1 Mg, 2 H, and 2CL and end up with the same five only their bonds have been rearranged, or in other words, they are joined up differently.
The question is asking to state the conclusion that can be formulated, base on the problem or the given analysis of the data, about the accuracy and precision and base on my research, i would say that the Accuracy is Poor but the Precision is Good. I hope this would help you
Answer:
CO2 (s) -->Co2 (g) will be the answer