Chapter 4B Solutions

Solutions Homogeneous mixture Solvent – substance present in the largest amount Solute – substance present in the smallest amount Aqueous solution – solutions with water as the solvent.

Types of Solutions Solute Solvent Example Gas Air ( O2, CO2 in N2) Liquid Water in air Carbonated beverages (CO2 in water) Vinegar (acetic acid in water) Solid Sugar water solid Stainless steel (Cr and Ni in Fe When something dissolves it dissociates – not all chemicals are soluble

Solubility The maximum amount of a solute that can be dissolved in a given amount of solvent at a constant temperature. Factors that affect rate of Solubility (increase the rate of dissolving). Pressure Temperature Polarity

Solubility Solutions can be classified into groups by how much solute is in solution. Saturated – contains as much solute as the solvent can hold at a given temperature. Unsaturated – less the maximum amount of solvent at a given temperature. Supersaturated – contains more solute than the solvent can hold at a given temperature.

Solution by Mass Percent Solutions are described by mass percent

Solutions by Mass Percent A solution is prepared by mixing 2.50 grams of calcium chloride with 50.0 grams of water. Calculate the mass percent of calcium chloride in this solution.

Solutions by Mass Percent A 75.0 gram sample of a solution is known to contain 23.8 grams of glucose. Calculate the mass percent of glucose in this solution.

Solutions by Mass Percent Vinegar is a solution of acetic acid in water and typically contains 5.00% acetic acid by mass. Calculate the mass of acetic acid in a 250.0 gram sample of vinegar.

Solutions by Mass Percent Concentrated hydrochloric acid solution contains 37.2 % by mass HCl. What mass of HCl is contained in 35.5 grams of concentrated HCl.

Molarity Molarity – concentration of a solution

Molarity Calculate the molarity of a solution prepared by dissolving 15.6 gram of solid KBr in enough water to make 1.25 L of solution.

Molarity Calculate the molarity of a solution prepared by dissolving 2.80 grams of solid NaCl in enough water to make a 135 ml of solution

Molarity What mass of NaNO3 is required to make 2.50 Liter of a 0.150 M solution of NaNO3?

Molarity What mass of (NH4)2SO4 is required to make 1.25 liter of 0.250 M solution of (NH4)2SO4?

Molarity-Ion Concentration Give the concentrations of all ions in each of the following solutions 1.20 M Na2SO4 0.750 M K2CrO4

Molarity-Ion Concentration How many moles of Na+ ions are present in 42.0 ml of a 0.350 M NaCl solution?

Molarity-Ion Concentration How many moles of Na+ ions are present in 42.0 ml of a 0.350 M of Na3PO4 solution?

Dilutions Process of adding more solvent to a solution. M1=molarity before dilution V1=volume before dilution M2=molarity after dilution V1=volume after dilution

Dilution What volume of 19 M NaOH must be used to prepare a 1.0 Liter of a 0.15 M NaOH solution?

Dilution What volume of water is needed to prepare 500.0 ml of a 0.250 M Ca(NO3)2 solution from a 5.00 M solution of Ca(NO3)2?

Titrations Combining a solution of know concentration with a solution of unknown concentration to determine the unknown. Equivalence point – when the reactants are equal molar. Indicator – dyes used in titrations to indicate equivalence point.

Titrations What volume of 0.115 M HCO4 solution is needed to neutralize 50.00 ml of 0.0875 M NaOH? 15.00 ml of acetic acid is titrated with 0.500 M NaOH. It takes 22.59 ml of NaOH. What is the molarity of the acetic acid? How many grams of AgBr are formed when 35.5 ml of 0.184 M AgNO3 are mixed with an excess of aqueous hydrobromic acid?