5. A vitamin contains 1.5 x 10' grams of zinc. How many moles of zinc are in the vitamin?

                      2.29 × 10⁻⁴ moles

Explanation:

Data Given:

                 Chemical Symbol of Zinc  =  Zn

                 Mass of Zinc   =  1.5 × 10⁻² g

                 A.Mass of Zinc  =  65.38 g.mol⁻¹

The Atomic Mass of Zinc can be obtained from periodic table. While, the mass is given in statement. Also, it is important to know the symbol because some elements exist in diatomic or polyatomic forms i.e. H₂, N₂, S₈ e.t.c.

                 Mole is the unit used to calculate the amount of substance. It has following general forms,

                                             Mole =  Mass / M.Mass

And,

                     Mole =  # of Particles / 6.022 × 10²³ particles.mol⁻¹

Hence, using first equation,

                     Moles  =  1.5 × 10⁻² g / 65.38 g.mol⁻¹

                     Moles =  2.29 × 10⁻⁴ moles

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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.