The properties of a solid compound that is mixed with and dissolved in a fluid without leaving any particles is called solubility.The only compounds that are notsoluble are ionic compounds.If you memorize a few rules or refer to a list of them, you can tell whether most ionic compounds will stay solid or not.If you can't see the change, you may need to know how to calculate the amount of dissolved molecule.
Step 1: You can learn about ionic compounds.
Each atom normally has a certain number of electrons, but sometimes they pick up an extra electron or lose one through a process known as electron transfer.The result is an electric charge.The negative and positive ends of 2 magnets bond together when an ion with a negative charge and a positive charge meet.An ionic compound is the result.Ions with negative charges are referred to as.The number of electrons in an atom is equal to the amount of protons.
Step 2: Understand how things work.
One end of the water molecule has a positive charge while the other is negative.When you drop an ionic compound in water, the water "magnets" will gather around it, trying to pull the positive and negative ion apart.Since the water will pull them apart, some ionic compounds aren't stuck together very well.Other compounds can stick together despite the water.The internal bonds of some compounds are similar to those of the water.A lot of compounds will be pulled apart, but the rest will stay together.
Step 3: The rules of solubility should be studied.
It's not always clear which compounds are insoluble and which are soluble because of the complex interactions between atoms.Look up the first ion in the compound to find out how it usually behaves, then check the exceptions to make sure the second one doesn't have an unusual interaction.If you want to check Strontium Chloride, look for Sr or Cl in the bold steps.Under it, check for exceptions.Sr is not listed as an exception.Under the rule, the most common exceptions are written.You are unlikely to see them in a typical chemistry class or laboratory.
Step 4: If compounds have alkali metals, be aware that they aresoluble.
Li, Na, K, Rb, and Cs are Alkali metals.The elements are called the Group IA elements.Every single compound has at least one of these ion.Li3PO4 is notsoluble.
Step 5: Understand that there are other compounds that are notsoluble.
These include compounds of NO, C2H3O2, NO2, and ClO4.These are the nitrates, nitrites, chlorate, and perchlorates.It is often abbreviated OAC.Hg(OAc)2 is insoluble.AgNO2 and KClO4 are notsoluble.
Step 6: The compounds of Cl, Br, and I are usually notsoluble.
halogen salts are made almost always by the chloride, bromide, and iodide ion.The result is insoluble if these pair with silver Ag, mercury Hg2, or lead Pb.Less common compounds made from pairs with copper Cu and thallium Tl are the same.
Step 7: You should know that compounds containing SO4 are usuallysoluble.
There are several exceptions to the sulfate ion formingsoluble compounds.The sulfate ion forms insoluble compounds with strontium Sr, barium Ba, lead Pb, silver Ag, calcium Ca, radium Ra, and diatomic Silver Ag2.Some people call silver sulfate and calcium sulfate soluble.
Step 8: You should know that compounds containing OH or S are insoluble.
The ion are hydroxide and sulfide.Remember how the alkali metals love forming compounds?Li, Na, K, Rb, and Cs all have the same chemistry.Sulfates are formed with the alkali earth's Group II-A ion: calcium Ca, strontium Sr, and barium Ba.The compounds resulting from hydroxide and an alkali earth have a small amount of bonds that stay together.
Step 9: CO3 and PO4 are insoluble.
You should know what to expect from your compound after one last check for carbonate andphosphate ion.The usual suspects are the alkali metals Li, Na, K, Rb, and Cs, as well as with Ammonium NH4.
Step 10: The Ksp is the product solubility constant.
You'll need to look it up on a chart in your textbook, because this constant is different for each compound.It is best to use your textbook's chart if it has one because the values can vary widely between charts.Unless otherwise stated, most charts assume you are working at 25oC.If you're dissolving PbI2, write down the product solubility constant.
Step 11: Write the equation.
Determine how the compound splits when it's dissolved.Write an equation with the Ksp on one side and the ion on the other.A molecule of PbI2 splits into three different parts.The total compound will always have a neutral charge if you look up the charge on 1 ion.The product solubility constant can be found in a solubility chart.I am to the second power since there are 2 I ion.
Step 12: Use variables to modify the equation.
If you know the number of molecule and ion, you can rewrite the equation as a simple algebra problem.Rewriting the variables representing the numbers of each ion in terms of x is possible if you set x equal to the amount of the compound that will be dissolved.Since there is one lead ion in the compound, the number of dissolved compound molecules will be the same.It's possible to set [Pb] to x.The number of I for each lead ion can be set at 2x squared.7.110 is the equation.
Step 13: If present, account for common ion.
If you are dissolving the compound in water, skip this step.If the compound is dissolved into a solution that already contains one or more of the common ion, the solubility is decreased.The ion effect is most notable in compounds that are mostly insoluble, and in these cases you can assume that the vast majority of the ions at equilibrium come from the ION already present in the solution.You can change the equation to include the molar concentration of the ion already in the solution.If our lead iodide compound was dissolved in a solution with 0.2 M lead chloride, we would rewrite our equation to reflect the change.Since x has a higher concentration than 0.2M, we can rewrite it as 7.110
Step 14: The equation can be solved.
If you solve for x, you will know the compound's structure.The answer will be based on the moles of the compound dissolved per liter of water.You might need a calculator to find the answer.The following is for water with no common ion.7.110 is 2x and 4x is 1x.This compound is insoluble, so it's a very small amount.