Answer:

Explanation:

Data:
Mass of NaCl = 4.6 g
Mass of water = 250 g
Calculations:
Mass of solution = mass of NaCl + mass of water = 4.6 g + 250 g = 254.6 g.

The substance most likely is an inert element because it is only composed of one kind of atom and cant be separated further. Also, it cannot be converted to another type of substance. An inert material doesn't react to any substance. Examples are Neon and Krypton.
A roller coaster reaches its maximum P.E when it is at the top ;)