 # Solutions Solute – what is dissolved

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Solutions Solute – what is dissolved
Solvent – what the solute is dissolved into. Aqueous solutions have water as the solvent.

Water solubility depends on:
Polarity of solute and solvent. Relative attractions of the ions for each other as opposed to the ions attraction for the water molecules

Strong electrolytes A solution of a strong electrolyte is able to conduct a current efficiently The ionic substance completely ionizes. Soluble salts, strong acids, strong bases

Weak Electrolytes Solutions that do not conduct electricity efficiently. Only a small amount of the ionic compound ionizes Insoluble or slightly soluble salts, weak acids or bases

Nonelectrolytes Solutions that do not conduct electricity. Solute is polar but not ionic so no ions can be produced. Molecular compounds in solution.

Molarity (M) M = moles of solute liters of solution

A solution of ethanol is prepared by dissolving 75
A solution of ethanol is prepared by dissolving 75.0 mL of ethanol (density = 0.79g/mL) in enough water to make mL of solution. What is the molarity of this solution?

Calculate the concentration of all ions present in a solution made from 1.00g of K2SO4 in mL of solution.

How would you prepare 500 mL of a 0
How would you prepare 500 mL of a 0.500M solution of sodium carbonate from the pure solid?

Dilutions Adding water to a stock or concentrated solution in order to prepare a lower molarity solution. Moles of solute before dilution =moles of solute after dilution

M=molarity; V=volume M1xV1 = moles of solute before dilution
M2xV2 = moles of solute after dilution M1xV1 = M2xV2

How would you prepare 250 mL of 6
How would you prepare 250 mL of 6.0M sulfuric acid from concentrated (18M) sulfuric acid?

Precipitation Reactions
When two solutions are mixed an insoluble product is formed. To predict the product of these reactions solubility rules must be known. Table 4.1 p. 152

Al(NO3)3(aq) + Ba(OH)2(aq) CaCl2(aq) + Na2SO4(aq)
Write the balanced molecular, the complete ionic, and the net ionic equations for the following FeSO4(aq) + KCl(aq) Al(NO3)3(aq) + Ba(OH)2(aq) CaCl2(aq) + Na2SO4(aq) K2S(aq) + Ni(NO3)2(aq

Solution Stoichiometry
Identify reactants and products Balance net ionic equation Calculate moles of reactants Determine limiting reactant Calculate moles of product Convert to grams or other unit

What volume of 0.100M Na3PO4 is required to precipitate all the lead(II) ions from mL of 0.250M Pb(NO3)2 ?

What mass of barium sulfate can be produced when 100. 0 mL of a 0
What mass of barium sulfate can be produced when mL of a 0.100M solution of barium chloride is mixed with mL of a 0.100M solution of iron(III) sulfate?

Acid –Base Reactions Acid- proton donor Base – proton acceptor
Acid + base salt + water Neutralization reaction.

HNO3(aq) + Al(OH)3 HC2H3O2(aq) + KOH(aq) Ca(OH)2(aq) + HCl(aq)
Write the balanced molecular, the complete ionic, and the net ionic equations for the following HNO3(aq) + Al(OH)3 HC2H3O2(aq) + KOH(aq) Ca(OH)2(aq) + HCl(aq)

Hydrochloric acid (75. 0 mL of 0. 250M) is added to 225. 0 mLof 0
Hydrochloric acid (75.0 mL of 0.250M) is added to mLof M Ba(OH)2 solution. What is the concentration of the excess H+ or OH- ions left in solution?

Oxidation-Reduction Reactions
Reactions where one or more electrons are transferred. The oxidation state or number of an element will change during the reaction. Rules for assigning oxidation numbers – Table 4.2 p.167

Species Oxidized - increase in oxidation state , lose electron(s) and act as the reducing agent.
Species Reduced - decrease in oxidation state, gain electron(s) and act as the oxidizing agent.

Assign oxidation states to all atoms
UO22+ As2O3 NaBiO3 Cl2 Mg2P2O7

Specify which of the following are redox reactions, identify the oxidizing agent, the reducing agent, the species being oxidized and the species being reduced Cu(s)+ 2Ag+(aq)  2Ag(s) + Cu2+(aq) HCl(g) + NH3(g)  NH4Cl(s) SiCl4(l)+ 2Mg(s) 2MgCl2(s) + Si(s)

Balancing Redox Equations
Write separate half reactions Balance each half reaction Elements except H and O Oxygen using water Hydrogen using H+ Charge using electrons

Balancing Redox Equations
Equalize electrons transferred by multiplying half reactions by whole numbers. Add half reactions together If the reaction is in a basic environment neutralize the H+ ions with OH- ions.

Balance the following in acid solution
Cr2O7(aq)+ Cl-(aq) Cr3+(aq) + Cl2(g) Pb(s)+PbO2(s)+H2SO4(aq)PbSO4(s) Mn2+(aq)+NaBiO3(s)Bi3+(aq)+MnO4(aq)

Balance the following in basic solution
Cr(s)+CrO42-(aq) Cr(OH)3(s) MNO4-(aq)+ S2-(aq) MnS(s) + S(s) CN-(aq)+MnO4-(aq)CN-(aq)+MnO2(s)