What gas is most abundant in a nebula

Figure 10-1 study figure 10-1. the strong nuclear force felt by a single proton in a large nucleus

Match the mixture with the substance// i really need on this guys (it’s a pic btw)

Asample of hydrated tin (ii) chloride (sncl2) has a mass of 4.90 g. when it is dehydrated, it has a mass of 4.10 g. which is the correct chemical formula for the hydrate? sncl2•2h2o          sncl2•4h2o          sncl2•6h2o