Semester Two Final Review 2016 Chemistry

Stoichiometry – Balanced Equations A balanced chemical equation tells the ratio of the number of moles of one compound to moles of another compound Another example… 2 CoBr3 + 3 CaSO4  3 CaBr2 + 1 Co2(SO4)3 3 moles of CaSO4 used to 1 mole of Co2(SO4)3 produced How many moles Co2(SO4)3 of can be produced if we start with 12 moles of CoBr3 and an excess of CaSO4?

Stoichiometry – The Box Method Use the box with grams! Moles is on the bottom in this box Balance the equation first if needed! Molar mass: add masses from the periodic table Down = divide; up = multiply The ONLY way to move between compounds is from moles to moles

Acids and Bases – The Box Method Use the box with liters! Moles is on the TOP in this box Down = divide; up = multiply The ONLY way to move between compounds is from moles to moles

Stoichiometry – The Box Method Write chemical formulas: + and - charges MUST CANCEL Oxide and hydroxide are NOT the same thing Balance the equation Use the box

Solutions Concentration and molarity (M) mean the same thing How much solute is dissolved in a solvent Most concentrated = highest molarity Least concentrated = lowest molarity

Solutions – Freezing Point Dissociation factor: how many particles a solute will break into in water Ionic (metal + nonmetal) = breaks apart Circle any polyatomic ions – the group stays together! Covalent (nonmetals) = stays together = df of 1 Freezing point calculations use molality (mol divided by kg)

Solutions – Solubility Graph Solubility is temperature dependent Saturated = contains the maximum amount of solute at that temperature Any point on the curve Precipitate = solid that forms #26-29 in packet

Acids and Bases – pH Calculations Use the flow chart! Acidic, basic, or neutral? Always find the pH to tell pH less than 7 = acidic pH greater than 7 = basic

Acids and Bases – Neutralization Reactions Double replacement reactions One product is ALWAYS water (H2O) CIRCLE polyatomic ions – they stay together Formulas: + and – charges must cancel

Now try problem #12 in your pink review packet! Solutions Example #1 What is the molarity of a solution in which 10.0 g of silver nitrate is dissolved in 500.0 mL of solution? Now try problem #12 in your pink review packet!

Now try problem #12 in your pink review packet! Solutions Example #1 What is the molarity of a solution in which 10.0 g of silver nitrate is dissolved in 500.0 mL of solution? Now try problem #12 in your pink review packet!

Now try problem #24 in your pink review packet! Solutions Example #2 What is the boiling point of a solution of 48.3 g of LiCl in 450 g of water? Now try problem #24 in your pink review packet!

Now try problem #28 in your pink review packet! Solutions Example #3 A saturated solution of sodium nitrate is cooled from 60oC to 20oC. How many grams of precipitate form? Now try problem #28 in your pink review packet!

Acids and Bases Example #1 Anion Ending Acid Name -ide hydro-(stem)-ic acid -ite (stem)-ous acid -ate (stem)-ic acid Name the following and determine whether the compound is an acid, a base, or neither one. a. HCl b. Be(OH)2 Now try problem #33 in your pink review packet!

Acids and Bases Example #2 Write the formulas of the following compounds. a. Nitrous acid b. Magnesium hydroxide c. Chloric acid Anion Ending Acid Name -ide hydro-(stem)-ic acid -ite (stem)-ous acid -ate (stem)-ic acid Now try problem #34 in your pink review packet!

Acids and Bases Example #3 Calculate the pH of a solution in which the [OH-] = 3.6 x 10-6. Is the solution acidic, basic, or neutral? Now try problem #39a in your pink review packet!

Acids and Bases Example #4 Calculate the [H+] of a solution in which the pOH = 7.2. Now try problem #40a in your pink review packet!

Acids and Bases Example #5 Write the complete balanced neutralization reaction for the reaction of phosphoric acid and barium hydroxide. Now try problems #43-44 in your pink review packet!

Acids and Bases Example #6 A 45 mL solution of H2SO4 is completely neutralized by 22 mL of 1.25 M NaOH. What is the molarity of the H2SO4 solution? Moles (mol) Molarity (M) Liters (L) Now try problem #45 in your pink review packet!

Acids and Bases Example #7 What is the molarity of H2SO4 if 55 mL is neutralized by 1.5 M NaOH according to the curve below? Moles (mol) Molarity (M) Liters (L) Now try problem #47 in your pink review packet!

Acids and Bases Practice A 60 mL solution of HCl is completely neutralized by 22 mL of 0.50 M Ba(OH)2. What is the molarity of the HCl solution? Moles (mol) Molarity (M) Liters (L) Now try problem #45 in your pink review packet!