Verb, 4 letters; makes what when mixed with hot water

If a plot weight (in g) vs. volume (in ml) for a metal gave the equation y= 13.41x and r^2=0.9981 what is the density of the metal?

This is a characteristic of the elements in the periodic table that shows a pattern. it may increase or decrease across or down the table.

What is bromine+calcium iodide--> calcium bromide +iodine balanced