It applies to both physical and chemical changes.
We tend to think the greater the mass, the greater the volume but that is not true. What weighs more a pound of lead or a pound of feathers? Obviously they are the same however there would be a lot more feathers than lead. Mass and volume are not really related.
It should be 8 O atoms. 3O atoms in Na2S2O3 and 5O atom in 5H2O. The reason there are 5 O atoms are because the 5 in front of H2O means you multiply each atom in the compound by that number (like the distributive property). The H2 molecule becomes 10 Hydrogen atoms (5*2) and the Oxygen becomes 5 Oxygen atoms (5*1). Then you add the 5O atoms to the 3O atoms which equals 8
Rain bc it’s hot then cools
