A1-m depth of stagnant water lies on top of a 0.35 cm thickness of nacl. at time t < 0, the water is pure. at time t 0, the salt begins to dissolve into the water. if the concentration of salt in the water at the solid-liquid interface is maintained at saturation (0.00685 mol nacl/cm3) and the diffusivity of nacl is 2.3c-005 cm2/s, independent of concentration, estimate, by assuming the water to act as a semi-infinite medium, the time of salt in the water when: (a) 10% of the salt has dissolved; ; (b) 50% of the salt has dissolved, and (c) 90% of the salt has dissolved. density of nacl 2.165 g/cm3. molecular weight of nacl 58.44 g/mol.

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).

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.