Solutions Acid-Base pH

Solutions Acid-Base pH ISCI 2002

Solutions • (1). Homeogeneousmixtureof ions or molecules • (2). Solid, liquidor gaseoussolutions • Metal alloy, air • (3). Partsof a solution • Solvent vs solute

Concentrations of Solutions • Concentrations: amount of solute present in a given mass or volume of solution. • % by Mass • % solute = mass of solute/mass of solution x 100% • A 10% glucose solution by mass contains 10.0 grams of glucose in 100 grams of solution. (90 grams of water and 10 grams of glucose)

Concentrations of Solutions • Example= 15 grams of glucose was added to 500 g (mL) of water. Determine the % concentration of glucose.

Molarity • What is a mole? Molarity? Molarity= moles / Liter • Mass of an element or compound that contains 6.02 x 1023 atoms or particles. • 1 mole of carbon = 12 grams

Molarity - Concentration • Molarity = number of moles of solute/number of liters of solution • If 39.10 grams of potassium were added to 1.0 L of water, what would the molarity of this solution be? • If approximately 11.5 grams were added to 1.0 liter of water, what would the molarity of this solution be?

Calculating Molarity • (1). 24 grams of carbonwas mixed with 1-L of water. Determine the molarityof the solution. • (2). 3.6 grams of HClwas added to one liter of water. Determine the molarityof the acid.

Concentrations • (1). Partspermillionor ppm • (2). 1particleof substance for every 999,999 other particles in that solution. • One drop of oil in a 40 gallon water tank would have a ppm of 1.

Solubility • (1). How much solutemay be dissolved in a in a specific amount of solvent. • Saturated, Undersaturated and Supersaturated • (2). SolubilityTable • Solubility of a substance at a specific temperature Supersaturated Solution

Solubility Table • (1). Determine the amount of Potassiumchloridethat can dissolve in 100g of water at 40 degrees. • (2). Potassiumnitrate? • (3). As temperature increases describe what happens to Cesiumsulfatessolubility.

Acids • (1). “Acidus” means sour • (2). Any chemical that donatesor produces hydrogenions(H+) in ‘aqueous’ solutions. • HCl + H2O -------- Cl- + H3O+ • Hydronium ion = hydrogen ion + water • (3). Strongerthe acidthe lowerthe pH

Acids • Ionization: acids or any molecular compound separates in solution to form ions. • Dissociation: ionic compounds separates into its ions in solution • StrongAcids: ionize close to 100% into H+ ions. (HCl; HNO3; H2SO4) • WeakAcids: ionize less than 5% into ions (Acetic Acid)

Bases • (1). Bases are bittertasting • (2). Characteristics • Slippery (think soap) • (3). Examples • Soap; baking soda; drain cleaners (NaOH) • (4). Basesaccepthydrogenionsor produceOH-(hydroxide) ions in aqueous solutions • NaOH --------- Na+ + OH- • HCl + H2O ------------- Cl- + H3O (water is a base)

Bases • Strong (soluble) bases: dissociate completely in aqueous solution (NaOH; LiOH; KOH) • WeakBases: ionize slightly in aqueous solutions (NH3)

Salts • Salt: contains a cation (other than H+) and an anion (other than OH-) • Salts are formed when acids react with bases.

Acid-Base Reactions • (1). When an acidis added to a basea saltand wateris formed. • (2). Example • HCl + NaOH ---------- _______(salt?) + H2O • HCl is added to calcium hydroxide? • (3). Neutralizationreaction

pH • (1). pH “powerofhydrogen” • (2). pH based on the concentrationof hydrogenions in solution. • (3). If: • H+ ions = OH- ions (neutral solution = 7 pH) • H+ > OH- then the solution is acidic (0-6 pH) • H+ < OH- then solution is alkaline (base) (8-14 pH)

pH Scale

Solutions Acid-Base pH