Asample of a white solid contains 0.212 g of magnesium and 0.140 g oxygen. what is the empirical formula of this compound?

In determining the empirical formula of a compound, you must convert the mass of each element to moles. Since the given mass for this problem is 0.212 grams of Magnesium and 0.140 grams of Oxygen, just divide the mass by the molar mass of Magnesium (24.305 g/mol) and Oxygen (16 g/mol).You’ll get 0.00872 moles of Magnesium and 0.00875 moles of Oxygen. You then divide the each mole value with the smallest calculated number of moles which is 0.00872. You will get an empirical formula of MgO. 

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.