What properties do substances which undergo sublimation process?
One of the properties substances need to have is a relatively high vapor pressure. Sublimation is a process in which a substance changes from solid to gas without having to pass the liquid state.
Just like by distillation, the different components of a mixture have different boiling and sublimation levels. If a mixture is heated up, the component that takes the least amount of energy to undergo sublimation will be evaporated out first, and the other component remains there in its original state.
Sublimation is, in fact, a universal phenomenon exhibited by all solids at temperatures below their triple points. However, sublimation is a scientifically and technically useful phenomenon only when the vapor pressure of the solid phase is high enough for the rate of vaporization to be rapid. Four of such solids include iodine, sulphur, naphthalene, and even dry ice (solid carbon dioxide).
What properties of substances can you observe and how do these properties determine the usefulness or hazards of a substance?
You can observe physical, chemical, and characteristic properties of a substance and can be used to determine the usefulness of a substance by, giving us information about the substance usually using our 5 senses which are physical properties. Or being able to describe the substances ability to undergo changes to its composition to produce one or more new substances, chemical property. Or even just being able to identify whether or not the substance is pure…
A mixture is when two or more substances which have been combined such that each substance retains its own chemical identity. When two or more substances react they lose there chemical identity and have to undergo a chemical reaction (or if they are not reversible reactions a series of reactions) to return to there original chemical. With a mixture you can just exploit the physical properties of one of the constituent parts to separate them…
if during a change the chemical composition of the reactants change or any new products are formed then the reactant is said to undergo chemical change. if the state, color, phase or any other physical properties of the reactant change without any change the chemical composition of the reactants or formation of any new substances then it is said to undergo physical change