REPUBLICA BOLIVARIANA DE VENEZUELA MINISTERIO DEL PODER POPULAR PARA L EDUCACION SUPERIOR UNIVERSITARIA INSTITUTOS UNIVERSITARIO POLITECNICO SANTIAGO MARIÑO MERIDA_MERIDA

EQUILIBRIUM ION UNIT

STUDENT ALDRY GARCIA CI :22685488ESC ING QUIMICA

TEACHER ARACELIS

MERIDA 11/ 06/2014

EQUILIBRIUN ION UNIT

Nerve and muscle cells encode information through changes in their membrane potentials. As we analyze the basis for such changes, an essential tool will be the concept of an equilibrium potential. Let's approach this topic by first looking at the concentrations of ions inside and outside cells and then at a simple system in which an electric potential difference develops. The ability to relate the equilibrium potential and concentration gradient for a particular ion has practical benefits.

EXPRESSING THE ION BALANCE

First, write the net ionic equation for the unbalanced reaction. If you are given a word equation to balance, you'll need to be able to identify strong electrolytes, weak electrolytes and insoluble compounds. Strong electrolytes completely dissociate into their ions in water. Examples of strong electrolytes are strong acids, strong bases, and soluble salts. Weak electrolytes yield very few ions in solution, so they are represented by their molecular formula (not written as ions). Water, weak acids, and weak bases are examples of weak electrolytes. The pH of a solution can cause them to dissociate, but in those situations, you'll be presented an ionic equation, not a word problem. Insoluble compounds do not dissociate into ions, so they are represented by the molecular formula. A table is provided to help you determine whether or not a chemical is soluble, but it's a good idea to memorize the solubility rules.Separate the net ionic equation into the two half-reactions. This means identifying and separating the reaction into an oxidation half-reaction and a reduction half-reaction.For one of the half-reactions, balance the atoms except for O and H. You want the same number of atoms of each element on each side of the equation.

Repeat this with the other half-reaction.Add H2O to balance the O atoms. Add H+ to balance the H atoms. The atoms (mass) should balance out now.Now balance charge. Add e- (electrons) to one side of each half-reaction to balance charge. You may need to multiply the electrons the the two half-reactions to get the charge to balance out. It's fine to change coefficients as long as you change them on both sides of the equation.Now, add the two half-reactions together. Inspect the final equation to make sure it is balanced. Electrons on both sides of the ionic equation must cancel out.

CLASSIFYING THE PROPERTIES OF AQUEOUS SOLUTION

Saturated SolutionSaturated solution is a solution to which no more solute can be added at a particular temperature. As temperature affects the solubility of a substance, a saturated solution at lower temperature may become a dilute solution at higher temperature. Unsaturated SolutionIt is a solution to which more solute can be added to dissolve. They are also otherwise called dilute solutions. The concentration of a solution is very low in an unsaturated solution. Solid Solutions It is the type of solution in which both solute and solvent are solids. For example metal alloys are a homogeneous mixture of two or more metals and their properties are entirely different from the parent metals. Liquid Solutions In a solution if both the solute and solvent are liquid they are called as liquid solutions. Ethanol in water, Benzene in carbon tetra chloride are example for liquid solutions.

IDENTIFY THE DIFFERENT ACID-BASE THEORIESArrhenius Acid-Base TheoryThe Arrhenius acid-base concept classifies a substance as an acid if it produces hydrogen ions H(+) or hydronium ions in water. A substance is classified as a base if it produces hydroxide ions OH(-) in water. This way of defining acids and bases works well for aqueous solutions, but acid and base properties are observed in other settings. Other ways of classifying substances as acids or bases are the Bronsted-Lowry concept and the Lewis concept.

 Bronsted-Lowry Acid-Base ConceptThe Bronsted-Lowry theory classifies a substance as an acid if it acts as a proton donor, and as a base if it acts as a proton acceptor. Other ways of classifying substances as acids or bases are the Arrhenius concept and the Lewis concept.

Lewis Acid-Base ConceptThe Lewis theory classifies a substance as an acid if it acts as an electron-pair acceptor and as a base if it acts as an electron-pair donor. Other ways of classifying substances as acids or bases are the Arrhenius concept and the Bronsted-Lowry concept.

 Bronsted-Lowry Acid-Base

CONSIDER DETERMINING THE DIFFERENCE IN PH AND THE STRENGTH OF AN ELECTROLYTE

nThe main function of the reference electrolyte is to, via the reference element and the reference junction, electrically connect the measured media to the pH meter. But not only to connect, you also want the electrolyte to have a stable connection. And if you speak in electrical terms that mean a stable electrical potential drop over the electrolyte. However, the electrolyte only has a stable connection as long as the concentration of the solution is stable.The traditional pH electrolyte is a potassium chloride solution (KCl, 3 mol/l). A KCl electrolyte establishes, in many cases and especially for laboratory use, the most reliable contact with the measured solution.

However, for demanding applications and especially for process online pH measurements, a gelled electrolyte or a solid polymer electrolyte has proven to be a simpler and more robust and rugged alternative.