In this introductory post from Berry Berry Easy on STPM Chemistry Form 6 titled Part 1 – Heterogeneous Ionic Equilibrium, you’ll be learning about definition relevant to heterogeneous ionic equilibrium such as dissolving, dissociation, solvent and solute, solubility, saturated and supersaturated, solubility product, common ion effect, molar solubility and gram solubility. Understanding and memorising the following definitions is crucial for your understanding of this topic.
[Tips: As with most of the opening posts of each chapters, the crucial thing to do is to first understand, then memorise the definitions involved. With this in the back of your head, you will have an easier time trying to understand concepts later, in the harder posts. So always try to recite them whenever you can.]
STPM Chemistry Form 6 Notes – Heterogeneous Ionic Equilibrium (Part 1)
- Dissolving – the breakdown of intermolecular forces between molecules as a solid becomes a solute within a solvent. The molecule remains intact when dissolving into solution.
- Dissociation – the breakdown of ionic bonds between atoms within a lattice structure as a salt turns into a solute within the solvent. The crystal lattice of the salt breaks apart when it dissociates into solution.
- Solvent – the species in greatest concentration into which the solute dissolves, or salt dissociates. A solvent must be a fluid.
- Solute – the species not in highest concentration that dissolves into the solvent, or in the case of a salt, dissociates.
- Solubility – a measurement of the degree of dissolving that a solute undergoes within a particular solvent.
- Saturated – the state of a solution at the point where no more solid (solute) can dissolve into solution. When an aqueous salt solution is saturated, the rate of dissociation of the salt equals the rate of precipitation.
- Supersaturated – the state of a solution where the amount of solid (solute) that is dissolved into solution is beyond the maximum amount at a given temperature. The solution is actually a suspension that when disturbed can form a precipitate rapidly.
- Solubility product (Ksp) – the equilibrium constant for a dissociation reaction, determined from the molar solubility according to standard rules for calculating equilibrium constant.
- Molar solubility – quantitative measurement of the maximum number of moles of solid (solute) that can dissolve into enough solvent to make one dm3 of solution under standard conditions.
- Gram solubility – quantitative measurement of the maximum number of grams of solid (solute) that can dissolve into enough solvent to make one hundred millimeters of solution under standard condition.
- Common ion effect – this cause in a reduction in the amount of solid (solute) that can dissolve into solution due to the presence in the solution of an ion that is also present in the solid. With the common ion effect, the ion causing the reduced solubility is present in solution at the beginning of the reaction, rather than being added once the solution has reached solubility equilibrium.
So this is the end of this introductory post to Heterogeneous Ionic Equilibrium for STPM Form 6 Chemistry students from Berry Berry Easy. In the next part, Part 2, Berry Readers will be treated to learning the solubility rules, or rules of generalisation of ionic solids in solutions. So stay tuned