Chapter Seven chemistry note

·         A solution is a homogeneous mixture in which one substance called the solute is uniformly dispersed and the other substance is called the solvent. The solute and solvent do not react with each other and can be mixed in varying proportions.

·         Sugar in sugar water is the solute and water is the solvent. Carbon dioxide in soda is the solute and the liquid is the solute.

·         Hydrogen bonds occur between molecules where a partially positive hydrogen is attracted to the strongly electronegative atoms of O, N, or F in other molecules.

·         In water, hydrogen bonds are formed by the attraction between the oxygen atom of one water molecule and a hydrogen atom in another molecule.

·         The attractive forces of several water molecules provide the energy to break the ionic bonds between Na and Cl ions in the NaCl crystal.

·         Solutes can be classified by their ability to conduct an electrical current. When solutes called electrolytes dissolve in water, they separate into ions, which are able to conduct electricity.

·         Non electrolytes will form but won’t form ions.

·         Solubility is used to describe the amount of a solute that can dissolve in a given amount of solvent

·         If a solute readily dissolves when added to the solvent, the solution does not contain the maximum amount of solute. This is unsaturated.

·         Saturated means that the liquid has dissolved all the solute that it can.

·         The solubility of most solids is grater as temperature increases, which means that solutions usually contain more dissolved solute at higher temperatures

·         The amount of solute dissolves in a certain amount of solution is called concentration of the solution.

o   Concentration  = amount of solute/amount of solution

·         Because the volumes of liquids or gases are easily measured, the concentrations of their solutions are often expressed as volume percent.

o   Volume percent  (% v/v)= volume of solute/volume of solution X 100%

·         A mass/volume percent is calculated by dividing grams of the solute by the mL of the solution and multiplying 100

o   Mass/volume percent (%m/v) = grams of solute/mL of solution X 100%

·         Molarity is the concentration that states the number of moles of solute in exactly 1L of solution.

o   Molarity (M) = moles of solute/liters of solution

·         Dilution is the process when a solvent is added to a solution in which increases the volume and decreases the concentration

o   C₁V₁ = C₂V₂

·         When the concentration is given as molarity (M), the moles of the solute are obtained from the volume (L) and the molarity

o   Moles of solute = molarity (moles/L) X volume (L)

·         Isotonic solutions exert the same osmotic pressure as body fluids; NaCl and D5 are the most isotonic

·         Hypotonic has a lower solute concentration so it the solution can flow into cells by osmosis, possible causing the cells to burst.

·         Hypertonic has a high solute concentration, so the water will be drawn to it, causing the cells to shrink.