Report issue Transcript Now we're going to say example 1. Consider the following compounds. Which has the highest concentration of OH- ions?
It also explores the relationship between the solubility product of an ionic compound and its solubility. What are solubility products, Ksp? Solubility products are equilibrium constants Barium sulphate is almost insoluble in water. It isn't totally insoluble - very, very small amounts do dissolve.
That's true of any so-called "insoluble" ionic compound. Over time, some of these will return from solution to stick onto the solid again. You get an equilibrium set up when the rate at which some ions are breaking away is exactly matched by the rate at which others are returning.
The position of this equilibrium lies very far to the left.
The great majority of the barium sulphate is present as solid. In fact, if you shook solid barium sulphate with water you wouldn't be aware just by looking at it that any had dissolved at all.
But it is an equilibrium, and so you can write an equilibrium constant for it which will be constant at a given temperature - like all equilibrium constants.
The equilibrium constant is called the solubility product, and is given the symbol Ksp. To avoid confusing clutter, solubility product expressions are often written without the state symbols. Even if you don't write them, you must be aware that the symbols for the ions that you write are for those in solution in water.
Why doesn't the solid barium sulphate appear in the equilibrium expression?
For many simple equilibria, the equilibrium constant expression has terms for the right-hand side of the equation divided by terms for the left-hand side.
But in this case, there is no term for the concentration of the solid barium sulphate. This is a heterogeneous equilibrium - one which contains substances in more than one state. In a heterogeneous equilibrium, concentration terms for solids are left out of the expression.
The simplest explanation for this is that the concentration of a solid can be thought of as a constant. Rather than have an expression with two constants in it the equilibrium constant and the concentration of the solidthe constants are merged to give a single value - the solubility product.
Solubility products for more complicated solids Here is the corresponding equilibrium for calcium phosphate, Ca3 PO4 2: And this is the solubility product expression: Just as with any other equilibrium constant, you raise the concentrations to the power of the number in front of them in the equilibrium equation.
There's nothing new here.
Solubility products only apply to sparingly soluble ionic compounds You can't use solubility products for normally soluble compounds like sodium chloride, for example.
Interactions between the ions in the solution interfere with the simple equilibrium we are talking about. The units for solubility products The units for solubility products differ depending on the solubility product expression, and you need to be able to work them out each time. Working out the units in the barium sulphate case Here is the solubility product expression for barium sulphate again: Each concentration has the unit mol dm So the units for the solubility product in this case will be: The units this time will be: It isn't very hard - just take care!
Solubility products apply only to saturated solutions Let's look again at the barium sulphate case. Here is the equilibrium expression again: Ksp for barium sulphate at K is 1.
In order for this equilibrium constant the solubility product to apply, you have to have solid barium sulphate present in a saturated solution of barium sulphate.
That's what the equilibrium equation is telling you.A-8 Selected Answers (a) gas (b) liquid (c) solid (d) gas (e) solid (f) solid lithium and potassium (a) chlorine, Cl (b) potassium, K (c) silicon, Si Because manganese is a metal, we expect it to be malleable. Protons and neutrons are in a tiny core of the atom called the nucleus.
CaCO3(s) ↔ Ca2+(aq) + CO(aq) Write the equilibrium expression for this dissolution. Solubility Equilibria CaCO3(s) ↔ Ca2+(aq) + CO(aq) K = [Ca2+(aq)][CO(aq)] = Ksp The equilibrium expression is called the solubility product (sp), because it only involves products of the concentrations of the dissolved species and not the solid.
The expression shown by Equation  does represent that of the Ksp for gypsum. So what then is the difference between the IAP and Ksp?
Simple, the Ksp represents a condition were equilibrium is achieved and the IAP is just the measured product of Ca2+ and SO activities in solution at that time.
AP* Chemistry Solubility Equilibrium As dissolution proceeds, the concentration of ions increases until equilibrium is established.
This occurs when the solution is Write the Ksp expression for each of the following reactions and find its value in the table above. Complete the following tasks, and then answer the question. a) Write the chemical equation corresponding to Ksp.
b) Write the defining expression for the thermodynamic on the solubility of NiCO3" lab": If HCl(aq) were added to write a balance chemical equation and a solubility product expression for its dissolution in water. AP Chemistry Lab Manual. Lab Notebook Guidelines 2. QRS lab 5. Determine the mass you will use of the M and the HCl.
Write a procedure that will determine the H for the reaction #2 above per mole of M. Write the Ksp expression.