Unformatted text preview: Chapter 4
• Solution – • Solvent –
• Solute –
3 Preparation of a solution
Solubility Solubility depends on: Temperature
For gases in liquids:
For solids and liquids:
Henry’s Law: Mathematically:
Henry’s law applies best when
4 Solution Terms
Saturated solutionUnsaturated solution –
Supersaturated solution –
Hydrated ionSolvated ion – 5 Rate of dissolution
Rate of reaction determined by 1 Chapter 4
Mass percentage –
Volume percentage –
Parts per million (ppm) –
Molarity (M) –
Millimolar (mM) –
Molality (m) –
Mole fraction of A
Normality- 7 Concentration example
Sodium carbonate (MM 106.0 g/mol) is a base which is sold commercially as aqueous
solution that is 10.0% sodium carbonate by mass. The solution has a density of 1.10
g/mL. The density of water is 0.997 g/mL. Determine its concentration in the following
(a) g solute/L soln (b) Mole fraction (c) Molarity (d) molality 2 Chapter 4
The reaction that occurs when current is drawn from a lead storage battery is described by the
Pb(s) +PbO2(s) + 2 H2SO4(aq) 2PbSO4(s) + 2H2O(l)
What volume of 0.500 M H2SO4 solution is required to produce 10.0 g of PbSO4(MM: 303.26 g/mol)? 9 Electrical Conductivity of Aqueous Solutions 10 Electrolytes
• Strong Electrolytes – • Strong Electrolytes – • Weak Electrolytes – • Nonelectrolytes – 11 Aqueous Solution process 12 Concentration of Ions
What is the concentration of Cl ions
for a 0.25 M CaCl2 solution:
CaCl2(s)→ Ca2+(aq)+ 2Cl–(aq)
Concentration of ions in solution: 3 Chapter 4
• The process of • Dilution with water does not alter the numbers of •
of solute before dilution =
after dilution 14 Dilution
What is the minimum volume of a 2.00 M NaOH solution needed to make 150.0 mL of a
0.800 M NaOH solution? 15 Types of reactions in Aqueous Solution
• Precipitation reactions
• Acid-base reactions
• Oxidation-reduction reactions 16 Precipitation Reactions
• Rules of solubility control what happens
• A solid
1. Writing solution chemistry reactions
2. Solubility rules
3. Net ionic equations
4. Solution chemistry stoichiometry 29 Formula Equation (Molecular Equation)
AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq) 30 Complete Ionic Equation
Ag+(aq) + NO3-(aq) + Na+(aq) + Cl-(aq) → AgCl(s) + Na+(aq) + NO3-(aq) 31 Net Ionic Equation
Ag+(aq) + Cl - (aq) → AgCl(s) 4 Chapter 4
Example: K2CrO4(aq) and Ba(NO3)2(aq)
Formula equation Complete ionic equation Net ionic equation 25 26 Precipitates
• Soluble –
• Insoluble – •
• Insoluble and slightly soluble are often used interchangeably.
Soluble and marginally soluble are often used interchangeably. Simple Rules for Solubility – Table 4-2 in text
1. Most nitrate (NO3-) salts are soluble.
2. Most alkali metal (group 1A) salts and NH4+ are soluble.
3. Most Cl-, Br-, and I- salts are soluble (except Ag+, Pb2+, Hg22+).
4. Most sulfate salts are soluble (except BaSO4, PbSO4, Hg2SO4, CaSO4).
5. Most OH- are only slightly soluble (NaOH, KOH are soluble, Ba(OH)2, Ca(OH)2 are
6. Most S2-, CO32-, CrO42-, PO43- salts are only slightly soluble, except for those containing the
cations in Rule 2. 32 Chemical Equations
Write the correct formula equation, complete ionic equation, and net ionic equation for
the reaction between cobalt(II) chloride and sodium hydroxide. 5 Chapter 4
33 Solving Stoichiometry Problems for Reactions in Solution
1. Identify the species present in the combined solution, and determine what reaction if any
2. Write the balanced net ionic equation for the reaction.
3. Calculate the moles of reactants.
4. Determine which reactant is limiting.
5. Calculate the moles of product(s), as required.
6. Convert to grams or other units, as required. 34 Solution Stoichiometry 1
10.0 mL of a 0.30 M sodium phosphate solution reacts with 20.0 mL of a 0.20 M lead(II)
nitrate solution (assume no volume change). What precipitate will form? What mass of precipitate will form? What is the concentration of nitrate ions left in solution after the reaction is
complete? What is the concentration of phosphate ions left in solution after the reaction is
complete? 39 5 Chapter 4
39 Acid and Bases
HCl(aq) + NaOH(aq) NaCl(aq) + HOH(l) Net ionic equation: • Too limiting because we would like to work with bases besides OH40 Acid–Base Reactions (Brønsted–Lowry)
NH3(aq) + HNO3(aq) NH4+(aq) + NO3-(aq) 41 Performing Calculations for Acid–Base Reactions
1. List the species present in the combined solution before any reaction occurs, and decide
what reaction will occur.
2. Write the balanced net ionic equation for this reaction.
3. Calculate moles of reactants.
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. 42 Acid–Base Titrations
• Quantitative analysis of acid base chemistry
• Titration –
analyte – 43 • Equivalence point – • Endpoint – Acid-base titration
For the titration of sulfuric acid (H2SO4) with sodium hydroxide (NaOH), how many moles
of sodium hydroxide would be required to react with 1.00 L of 0.500 M sulfuric acid to
reach the endpoint? 6 Chapter 4 44 Oxidation-Reduction Reactions
• Redox reaction –
Oxidation and Reduction must occur
Oxidizing agent –
Reducing agent – 51 Rules for Assigning Oxidation States
1. Oxidation state of an atom in 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)
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 Oxidation states
Find the oxidation states for each of the elements in each of the following compounds:
PCl5 52 CO32- SF4 MnO2 7 ...
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