18. c
19. A
20. decomposition reaction
21. 4
22. 0.04%
Density is the mass of compound divided by its volume can be shown as follows:


40 mL of snow having 20 g of mass calculated from density.
Now, 10 cm of snow = 3.93 inches = 20 g
As, 10 inches of rain will produce 11 inches of ice as the volume of ice is bigger than rain water.
10 inches rain = 11 inches snow
3.93 inches of snow produced by

Thus, 3.57 incehs of rain produces by 10 cm snow.
No. Magnesium, and Bromine are a chemical compound when put together.
Neither Bromine, nor Magnesium react with any sort of water.
A physical property is what a substance is like; it's directly observable. On the other hand, a chemical property is how a substance behaves; its reactivity.
Examples of a physical property are: color, texture, boiling point, freezing point, and melting point.
Examples of a chemical property are: flammability, combustion, and formation of a precipitate.