CHM152 Lecture Lecture #1 (Review) 1) Balancing Red-ox Reactions 2) Stoichiometry 3) Concentration of Solutions

 Balancing Red-ox Reactions  H o Method  H +1 + e -1  H o  Works for Net ionic Reactions Complete Reactions Organic Reactions  The Rules

 Half-Reactions  “Groupies”  Balance Charge with H +1 or OH -1 (acid/Base) acid is the default  Balance oxygen atoms with H 2 O  Balance hydrogen atoms with H o  H o lost equals H o gained  Quick Check (charge or mass balance)

MnO C 2 O 4 -2  CO 2 + Mn +2

MnO C 6 H 5 CH 3  C 6 H 5 CO 2 + Mn +2

 Stoichiometry Mass-mass Problems 1) Balanced Reaction 2) Molecular Mass of known and unknown 3) Moles of Known 4) Moles of Unknown 5) Mass of Unknown Grams Known  Moles Known  Moles Unknown  Grams unknown

a)Calculate the number of Liters of hydrogen gas formed by the reaction of 300. mL of 3.0 molar HCl solution with 100. grams of impure zinc metal ( 45.0 % Zn) at 40 o C and at 700 torr of atmospheric pressure. b)What is the limiting reagent? c)How much excess reactant remains after the reaction has reached completion? d)If only 8.8 liters of hydrogen gas is actually collected, calculate the percent yield for the process

Calculate the number of Liters of hydrogen gas formed by the reaction of 300. mL of 3.0 molar HCl solution with 100. grams of impure zinc metal ( 45.0 % Zn) at 40 o C and at 700 torr of atmospheric pressure.

What is the limiting reagent?

How much excess reactant remains after the reaction has reached completion?

If only 8.8 liters of hydrogen gas is actually collected, calculate the percent yield for the process

 Concentration of Solutions 1) Mass percent- 1) Molarity- 2) molality- 3) Parts per million- 4) Micrograms per milliLiter-