1.List the species present in the combined solution before 2. Write the balanced net ionic equation for this reaction. 3. Calculate moles of reactants. 78
4. Determine the limiting reactant, where appropriate. 5. Calculate the moles of the required reactant or product. 6. Convert to grams or volume (of solution), as required. 79
Some examples of strong acids and bases Strong Acids Strong Bases HCl NaOH HNO 3 KOH H 2 SO 4 HCLO 4 80
Exercise In the balanced molecular equation for the neutralization of sodium hydroxide with sulfuric acid, the product are: (a) NaSO 4 + H 2 O (b) NaSO 4 + 2H 2 O (c) 2NaSO 4 + H 2 O (d) Na 2 S + 2H 2 O (e) Na 2 SO 4 + 2H 2 O 81
Ans: (e) Na 2 SO 4 + 2H 2 O 82
Exercise How many mL of a 0.800 M NaOH solution is needed to just neutralize 40.00 mL of a 0.600 M HCl solution! 83
Ans 30.0 mL NaOH solution 84
Exercise What volume of a 0.100 M HCl solution is needed to neutralize 25.0 mL of 0.350 M NaOH! 85
Ans 8.75 x 10 -2 L 86
Acid – Base Titrations Titration – delivery of a measured volume of a solution of known concentration (the titrant) into a solution containing the substance being analyzed (the analyte). Equivalence point – enough titrant added to react exactly with the analyte. Endpoint – the indicator changes color so you can tell the equivalence point has been reached. 87
Titration of an acid with a base (a) Titrant (base) is in buret, and the flask contains the acid solution along with a small amount of indicator. (b) As base added drop by drop to the acid solution in the flask during the titration, the indicator changes color, but color disappear on mixing 88 (C ) Equivalence point is marked by a permanent indicator color change
Redox Reactions or Oxidation- Reduction Reactions Reactions in which one or more electrons are transferred. 2Na(s) + Cl 2 → 2NaCl(s) Sodium solid, which contains neutral sodium atoms, reacts with chlorine gas, which contains diatomic Cl 2 molecules, to form the ionic solid NaCl, which contains Na + and Cl - ions. Electrons are transferred from the hydrogen to the chlorine 89
Reaction of Sodium and Chlorine 90
Rules for Assigning Oxidation States 1. Oxidation state of an element = 0 2. Oxidation state of monatomic ion = charge of the ion 3. Oxygen = 2 in covalent compounds (except in peroxides where it = 1) 91
Rules for Assigning Oxidation States 4. Hydrogen = +1 in covalent compounds 5. Fluorine = 1 in compounds 6. Sum of oxidation states = 0 in compounds 7. Sum of oxidation states = charge of the ion in ions 92
Exercise Assign oxidation states to each of the atoms in the following compounds: (a) CaF 2 (b) CO 2 (c) H 2 O (d) SF 6 94
Ans (a)Fluorine has a greater attraction for electrons than calcium, and it has a charge of -1 (rule # 3). Therefore, calcium must be +2, so that the overall charge balances at zero. Notice that calcium is in group 2A. Metals in groups 1A and 2A always have an oxidation state equal to their group number when in compounds.
You've reached the end of your free preview.
Want to read all 110 pages?
- Fall '13
- Chemistry, Sodium chloride, Sodium hydroxide