Determine whether each observation describes a chemical or a physical property 1. When a piece of Sodium metal is placed in a test tube with water, the Sodium fizzes and
bubbles of gas are produced.
2. When salt is added to water in a test tube, the salt dissolves.
3. When water is placed in a freezer at zero degree selcious it becomes ice.
4. When an iron bicycle is left outdoors and is exposed to moist air, it gets rusty.

chemical, physical, physical, chemical

Explanation:

both rust and bubbles are products of chemical change whilst freezing ad dissolving are physical.

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)

un recipient conține 6,4 moli de gaz. gazul hidrogen reprezintă 25% din totalul kilometrilor din container. în cazul în care presiunea totală este de 1.24 atm ceea ce este