This investigation is based on the Arrhenius law, A formula created by Professor Svante Arrhenius that combines the Boltzmann distribution law with the concept of activation energy (Stephen Lower 2011a) to depict one of the most important relationships between temperature and rate of reaction in chemistry to date. In the formula,
K = e ≈ 2.71828
A = Arrhenius’ constant = Activation Energy
RT = Average kinetic energy (Universal gas constant × Temperature in Kelvins) In this experiment, the main focus is placed on the Arrhenius plot, which is derived through the manipulation of the Arrhenius equation to remove its exponential form by taking the natural log of both sides of the equation which forms lnk=lnA-E_A/RT A…show more content… This topic appealed to me, as it seemed like a sound concept in theory, but could not find any discussion based on using the Arrhenius plot for physical processes.
2.1 Sublimation; an endothermic process
Sublimation is the term describing the transition of a substance from the solid phase to the gas phase without passing through an intermediary liquid phase. (Anne Marie Helmenstine 2014a) It is a physical change of state, which occurs at temperatures and pressures below the triple point of the substance, the point where the temperature and pressure causes the 3 phases: solid, liquid and vapour, of a single component system to be in equilibrium. (Blackwell Scientific Publications Oxford 1997) This definition shows that sublimation is a purely physical process; so a substance does not undergo a chemical reaction during sublimation.
This diagram represents a typical endothermic reaction: Fig. 2: Endothermic reaction enthalpy change (hferrier n.d.)
As displayed in figure 2, a substance requires kinetic energy greater or equal to its activation energy in order for it to change from its initial form to its product. The activation energy shown is one of the pathways that a reaction takes with respect to the pressure that it is subjected to. Consider that for a substance to change from its solid phase to its gas phase the bonds are all fixed in a position and when the particles have enough energy, they are able to