DOCSLIB.ORG

Acids and Bases Are Chemical Compounds That Occur Regularly in 'Everyday Life'

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Acids and Bases Are Chemical Compounds That Occur Regularly in 'Everyday Life' CHEM, 2nd edition Cengage Learning Chapter 9 Acid-base reactions Acids and bases are chemical compounds that occur regularly in 'everyday life'. These two types of substances have opposite properties. They often occur in the foods we eat. Shawn McDonald Linn-Benton Community College Types of Electrolytes • Salts are water-soluble ionic compounds. All are strong electrolytes. Example: NaCl • Acids form H+1 ions in water solution. • Bases combine with H+1 ions in water solution. Bases increase the OH-1 concentration of the solution. -1 +1 May either directly release OH or pull H off H2O molecule. If the latter, this forms OH- ion and a different positively charged ion. 2 Properties of Acids • Sour taste. Like biting into a lemon... • React with “active” metals. I.e., Al, Zn, Fe, but not Cu, Ag or Au. 2 Al + 6 HCl AlCl3 + 3 H2 Corrosive. To Al (mid-right) and skin! • React with carbonates, producing CO2. Marble, baking soda, chalk, limestone. CaCO3 + 2 HCl CaCl2 + CO2(g) + H2O • Change color of vegetable dyes. Blue litmus turns red. Picture at right. • React with bases to form ionic salts and water. Called a neutralization. 3 Common Acids Chemical name Formula Uses Strength Nitric acid HNO3 Explosive, fertilizer, dye, glue Strong Explosive, fertilizer, dye, glue, Sulfuric acid H SO Strong 2 4 batteries Metal cleaning, food prep, ore Hydrochloric acid HCl Strong refining, stomach acid Fertilizer, plastics and rubber, Phosphoric acid H PO Moderate 3 4 food preservation Plastics and rubber, food Acetic acid HC H O Weak 2 3 2 preservation, vinegar Hydrofluoric acid HF Metal cleaning, glass etching Weak Carbonic acid H2CO3 Soda water Weak Boric acid H3BO3 Eye wash Weak 4 Structures of Acids • Binary acids have acid hydrogens attached to a nonmetal atom. 2 types of elements only. HCl, HF Write the H atom first, then the nonmetal atom. Dissociate in water to form H+ ions and Hydrofluoric acid nonmetal anions (such as Cl- or F-) 5 Structure of Acids • Oxyacids have acid hydrogens attached to an oxygen atom. H2SO4, HNO3 Also write the H atom(s) first, then the polyatomic ion group. Will dissociate when put into water, to give H+ ions and a polyatomic anion - 2- (like NO3 or SO4 ) 6 Structure of Acids • Carboxylic acids have COOH group. HC2H3O2, H3C6H5O3 Component of vinegar • Only the first H in the formula is acidic. The H is on the COOH. Lemons and limes Apples and wine 7 Properties of Bases • Also known as alkalis. • Taste bitter. Alkaloids = Plant product that is alkaline. Often poisonous. Potato and tomato shoots. • Solutions feel slippery. • Change color of vegetable dyes. Occurs in hemlock bark, Different color than acid. repels beetles. Red litmus turns blue. The dye in the paper reacts with OH- from base. • React with acids to form ionic salts. Neutralization. Negates taste and metal dissolving power of acids. 8 Common Bases Chemical Common Formula Uses Strength name name Sodium Lye, Soap, plastic, NaOH Strong hydroxide caustic soda petrol refining Potassium Caustic Soap, cotton, KOH Strong hydroxide potash electroplating Calcium Ca(OH) Slaked lime Cement Strong hydroxide 2 Sodium NaHCO Baking soda Cooking, antacid Weak bicarbonate 3 Magnesium Milk of Mg(OH) Antacid Weak hydroxide 2 magnesia Detergent, Ammonium NH OH, Ammonia 4 fertilizer, Weak hydroxide {NH (aq)} water 3 explosives, fibers 9 Structure of Bases • Most ionic bases contain OH ions. NaOH, Ca(OH)2 2- • Some contain CO3 ions. CaCO3 NaHCO3 • Molecular bases contain structures that react with H+. Mostly amine groups (N atoms). Caffeine has three amine type groups with CH2 group attached. 10 9-1b What is an acid or a base? • An acid–base reaction is any reaction in which an H+ is transferred. Does not have to take place in aqueous solution. Broader definition than Arrhenius. • An acid is a H+ donor; A base is a H+ acceptor. Either can be a molecule or an ion. Since H+ is a proton, acid is a proton donor and base is a proton acceptor. Base structure must contain an atom with an unshared pair of electrons to bond to H+. • In the reaction, the acid molecule gives an H+ to the base molecule. H–A + :B :A– + H–B+ 11 Amphoteric Substances • Amphoteric substances can act as either an acid or a base. They have both a transferable H atom and an atom with a lone pair. • HCl(aq) is acidic because HCl transfers an H+ to + H2O, forming H3O ions. Water acts as base, accepting H+. – + HCl(aq) + H2O(l) → Cl (aq) + H3O (aq) + • NH3(aq) is basic because NH3 accepts an H from – H2O, forming OH (aq). Water acts as acid, donating H+. + – NH3(aq) + H2O(l) NH4 (aq) + OH (aq) Thus water is amphoteric, it can act as a base with an acid, or as an acid with a base. Its nature is the opposite of the compound with which it is interacting. 12 An example acid-base reaction – +: In the reaction H2O + NH3 HO + NH4 water ammonia hydroxide ion ammonium ion – H2O and HO constitute an acid/conjugate–base pair. If hydroxide ion accepts a proton it will revert to a water molecule. + NH3 and NH4 constitute a base/conjugate–acid pair. If the ammonium ion donates a proton to a base, it will revert to the ammonia molecule. 13 Example—Identify the Brønsted–Lowry acids and bases and their conjugates in this reaction. + - C. HNO3(aq) + H2O(l) H3O (aq) + NO3 (aq) 14 Neutralization Reactions + - • H + OH H2O net ionic eqn. • Acid + base salt + water • Double-displacement reactions. Salt = cation from base + anion from acid. Sometimes the salt in insoluble. Cation and anion charges stay constant. H2SO4 + Ca(OH)2 → CaSO4 + 2 H2O • Some neutralization reactions are gas evolving, where H2CO3 (carbonic acid) decomposes into CO2 and H2O. H2SO4 + 2 NaHCO3 → Na2SO4 + 2 H2O + 2 CO2 sulfuric acid sodium bicarbonate sodium sulfate water carbon dioxide gas 15 Example — Write the equation for the reaction of aqueous perchloric acid with strontium hydroxide. 1. Write the formulas of the reactants. HClO4(aq) + Sr(OH)2(aq) 2. Determine the ions present when each reactant dissociates. + − 2+ − (H + ClO4 ) + (Sr + OH ) 3. Exchange the ions. H+1 combines with OH-1 to make H2O(l). Like other double displacements. + − 2+ − 2+ − (H + ClO4 ) + (Sr + OH ) (Sr + ClO4 ) + H2O(l) 16 Write the equation for reaction of aqueous perchloric acid with strontium hydroxide, Continued. 4. Write the formulas of the products. Cross charges and reduce subscripts if possible. HClO4(aq) + Sr(OH)2(aq) Sr(ClO4)2 + H2O(l) 5. Balance the equation. Each atom and group on left vs. right side of the equation. May be quickly balanced by matching the numbers of H and OH to make H2O. Coefficient of the salt is always 1. 2 HClO4(aq) + Sr(OH)2(aq) Sr(ClO4)2 + 2 H2O(l) 17 Write the Equation for reaction of aqueous perchloric acid with strontium hydroxide.Continued 6. Determine the solubility of the salt. Sr(ClO4)2 is soluble (look up in solubility table). 7. Write an (s) after the insoluble products and an (aq) after the soluble products. 2 HClO4(aq) + Sr(OH)2(aq) Sr(ClO4)2(aq) + 2 H2O(l) The reaction occurs since one of the products formed is water, and water molecules mainly stay as molecules and don't ionize very much. 18 9-2 Strong or Weak • A strong acid is a strong electrolyte. Practically all the acid molecules ionize, →. completely • A strong base is a strong electrolyte. Practically all the base molecules form OH– ions, either through dissociation or reaction with water, →. completely • A weak acid is a weak electrolyte. Only a small percentage of the molecules ionize, . • A weak base is a weak electrolyte. Only a small percentage of the base molecules form OH– ions, either through dissociation or reaction with water, . 19 Strong Acids • The stronger the acid, the more willing it is to donate HCl H+ + Cl- + - H. HCl + H2O H3O + Cl Use water as the standard base. • Strong acids donate practically all their H’s. 100% ionized in water. Strong electrolyte. + • [H3O ] = [strong acid]. [ ] = molarity. No HCl is left after you dissolve the compound in water. 20 Strong Acids, Continued Hydrochloric acid HCl Hydrobromic acid HBr Hydroiodic acid HI Nitric acid HNO3 Perchloric acid HClO4 Sulfuric acid H2SO4 21 Strong Acids, Continued Pure water HCl solution HCl is a strong electrolyte. Its Water is not an electrolyte and solution will conduct current. will not conduct current. 22 Weak Acids • Weak acids donate a small HF H+ + F- fraction of their Hs. + - HF + H2O H3O + F Most of the weak acid molecules do not donate H to water. Often less than 1% ionized in water. + • [H3O ] << [weak acid]. Most HF stays in this molecular form, does not ionize in water to + + form H or H3O 23 Weak Acids, Continued Hydrofluoric acid HF Acetic acid HC2H3O2 Formic acid HCHO2 Sulfurous acid H2SO3 Carbonic acid H2CO3 Phosphoric acid H3PO4 Stronger attraction between H and F than between H+ and water 24 Weak Acids, Continued HF in water is a weak electrolyte and only conducts electricity poorly – note dimness of light bulb. Pure water HF solution 25 Degree of Ionization • The extent to which an acid ionizes in water depends in part on the strength of the bond between the acid H+ and anion compared to the strength of the bond between the acid H+ and the O of water. − + HA(aq) + H2O(l) A (aq) + H3O (aq) In other words, which is stronger? the H-A bond or the H-O bond in the hydronium ion.
Load more

Recommended publications
  • Chapter 4: Aqueous Reactions and Solution Stoichiometry
    ١٤٣٦/٢١/١٢ CHAPTER 4: A QUEOUS REACTIONS AND SOLUTION STOICHIOMETRY GENERAL PROPERTIES OF AQUEOUS SOLUTIONS A solution is a homogeneous mixture of two or more substances. A solution in which water is the dissolving medium is called an aqueous solution. ١ ١٤٣٦/٢١/١٢ SOLUTE VS . S OLVENT The substance present in the greatest quantity is called the solvent. Water is considered the universal solvent because of its ability to dissolve many substances. The other dissolved substances are called the solutes . A solvent dissolves a solute. ELECTROLYTES A substance whose aqueous solutions contain ions is called an electrolyte because it will allow electric current to flow through it. Example: NaCl A substance that does not form ions in solution is called a nonelectrolyte. Example: C12 H22 O11 ٢ ١٤٣٦/٢١/١٢ IONIC COMPOUNDS IN WATER When ionic compounds dissolve in water the ions separate and are surrounded by water molecules. Once the ions have separated, they can move and conduct electricity. In the crystalline form they cannot move or conduct electricity. The solvation process helps stabilize the ions in solution and prevents the cations and anions from recombining. IONIC COMPOUND IN WATER Water molecules are polar and have a δ+ and δ- side. The more electronegative oxygen atoms are attracted to the positive ions. The less electronegative hydrogen atoms are attracted to the negative ions. ٣ ١٤٣٦/٢١/١٢ Ionic Compounds : undergo dissociation: process by which many ionic substances dissolve in water, the solvent pulls the individual ions from the crystal and solvates them. _ {NaCl + H2O} Polar water molecule + + H2O Dissociation H O NaCl 2 + - (s) Na (aq) + Cl (aq) Hydration of sodium chloride ٤ ١٤٣٦/٢١/١٢ MOLECULAR COMPOUNDS IN WATER When a molecular compound dissolves in water, the solution usually consists of intact molecules (neutral) dispersed throughout the system.
    [Show full text]
  • Exp 6 TP Manual
    AP Chemistry By Satellite Laboratory Manual Instructor's Edition EXPERIMENT 6: CONDUCTIVITY Contents Page Reagents...........................................................................6-2 Equipment........................................................................6-4 Useful Experimental Comments..........................................6-5 Pre–laboratory Questions...................................................6-7 Experimental Write–up .....................................................6-8 Post–laboratory Questions.................................................6-24 Instructor Evaluation Sheet...............................................6-28 AP CHEMISTRY BY SATELLITE 6 - 1 INSTRUCTOR LAB MANUAL Reagents CHEMICAL Quantity CHEMICAL Quantity acetic acid, 0.1 M 15 mL methanol 15 mL acetic acid, 1.0 M 50 mL nickel chloride hexahydrate, 0.1 M 15 mL ammonium acetate, 0.1 M 15 mL nickel nitrate hexahydrate, 0.1 M 15 mL ammonium chloride,0.1 M 15 mL nitric acid, 0.1 M 15 mL ammonium hydroxide, 0.1 M 15 mL potassium chloride, 0.1 M 15 mL ammonium sulfate, 0.1 M 15 mL potassium iodide 1 g ammonium thiocyanate 1 g potassium iodide, 0.1 M 15 mL barium hydroxide octahydrate, 0.1 M 15 mLpotassium nitrate, 0.1 M 15 mL calcium carbonate (ppt. chalk) 9 g silver nitrate, 0.1 M 15 mL calcium hydroxide, sat'd 15 mL sodium acetate trihydrate, 0.1 M 15 mL cobalt chloride hexahydrate, 0.1 M 15 mL sodium carbonate 1 g cupric chloride dihydrate, 0.1 M 15 mL sodium chloride 1 g ethanol 15 mLsodium chloride, 0.1 M 15 mL ferric nitrate nonohydrate 1 g sodium hydroxide, 0.1 M 15 mL hydrochloric acid, 1.0 M 50 mL sucrose 1 g hydrochloric acid, 0.1 M 5 mL sulfuric acid, 0.5 M 50 mL lead (II) nitrate 1 g sulfuric acid, 0.1 M 5 mL lead (II) nitrate, 0.1 M 15 mL Solution Preparation Use the table below to prepare the solutions of acids and bases.
    [Show full text]
  • Acids and Bases • Act Corrosive
    14.1 Acids • Produce H+ ions in water Chapter 14: • Taste sour Acids and Bases • Act Corrosive • Turn blue litmus paper red CHM 130 GCC Chemistry http://www.wisc-online.com/Objects/ViewObject.aspx?ID=GCH6204 http://phet.colorado.edu/en/simulation/acid-base-solutions 14.2 Bases 14.2 Arrhenius Acids and Bases • Produce OH- ions in water • Acids produce H+ in aqueous solutions • Taste bitter, chalky • HCl (aq) H+ (aq) + Cl- (aq) • Feel soapy, slippery • Bases produce OH- in aqueous solutions • Turn red litmus paper blue • NaOH (aq) Na+ (aq) + OH- (aq) Arrhenius Acids and Bases 14.3 Bronsted-Lowry Acids and Bases Which is the acid and which is the base? Acid is proton (H+) donor: (loses H+) Base is proton (H+) acceptor: (gains H+) 2 HNO3 + Ca(OH)2 2 H2O + Ca(NO3)2 _________ is the Arrhenius acid. + - HCl + NH3 NH4 + Cl loses H+ gains H+ __________ is the Arrhenius base. acid base 1 Molarity / Concentration pH Scale [ ] means concentration or molarity; M = mol / L Neutral Strongly Strongly Weakly Weakly basic [H+] = mol/L of H+ ions acidic acidic basic In pure water, [H+] = [OH-] 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 [H+] > [OH-], the solution is ??? Acidic Basic [H+] < [OH-], the solution is ??? Neutral + + - - http://phet.colorado.edu/en/simulation/molarity [H ]>[OH-] [H ] = [OH ] [OH ]>[H+] http://phet.colorado.edu/en/simulation/ph-scale pH of Some Common Items pH Scale pH = -log[H+] or [H+] =10-pH [H+] = 10-1 or 0.1mol/L so pH = [H+] = 10-5 mol/L………..
    [Show full text]
  • Net Ionic Equations
    Appendix B Net Ionic Equations Introduction For reactions which occur in aqueous solution, the net ionic equation is particularly useful since only those species which participate in the reaction, i.e. reacting species, are included. The principal step in writing the net ionic equation is to determine which molecular species or salts are strong electrolytes in aqueous solution. Therefore, it is necessary to have a complete understanding of strong electrolytes before proceeding to the writing of net ionic equations. Strong Electrolytes In aqueous solution, strong electrolytes dissolve and dissociate (separate) 100% to form ions. Thus, an aqueous solution of a strong electrolyte contains a relatively high concentration of ions. For example, when dissolved in water, the ionic compound NaCl is classified as a strong electrolyte. As a result, NaCl(aq) really exists in solution as dissociated and separated ions of Na+(aq) and ClG(aq). Neutral formula units of NaCl do not exist dissolved in solution. Strong acids, strong bases, and soluble ionic compounds are classified as strong electrolytes in aqueous solution. Most general chemistry books agree that the seven compounds given below are strong acids (ergo strong electrolytes) when dissolved in water. Consequently, an aqueous solution of the Strong Acids HCl(aq) HClO4(aq) H2SO4(aq) HBr(aq) HClO3(aq) HNO3(aq) HI(aq) strong acid perchloric acid, HClO4(aq), actually consists of dissociated and separated ions of + H (aq) and ClO4G(aq). Neutral molecules of HClO4 do not exist dissolved in solution. Likewise, an aqueous solution of the strong acid hydrochloric acid, HCl(aq), really consists of H+(aq) and ClG(aq).
    [Show full text]
  • Chapter 4: Reactions in Aqueous Solutions
    CHAPTER 4: REACTIONS IN AQUEOUS SOLUTIONS CHAPTER 4 REACTIONS IN AQUEOUS SOLUTIONS 4.6 (a) is a strong electrolyte. The compound dissociates completely into ions in solution. (b) is a nonelectrolyte. The compound dissolves in water, but the molecules remain intact. (c) is a weak electrolyte. A small amount of the compound ionizes in water. 4.7 When NaCl dissolves in water it dissociates into Na and Cl ions. When the ions are hydrated, the water molecules will be oriented so that the negative end of the water dipole interacts with the positive sodium ion, and the positive end of the water dipole interacts with the negative chloride ion. The negative end of the water dipole is near the oxygen atom, and the positive end of the water dipole is near the hydrogen atoms. The diagram that best represents the hydration of NaCl when dissolved in water is diagram (c). 4.8 Ionic compounds, strong acids, and strong bases (metal hydroxides) are strong electrolytes (completely broken up into ions of the compound). Weak acids and weak bases are weak electrolytes. Molecular substances other than acids or bases are nonelectrolytes. (a) nonelectrolyte (Water is actually a very weak electrolyte.) (b) strong electrolyte (ionic compound) (c) strong electrolyte (strong acid) (d) weak electrolyte (weak acid) (e) nonelectrolyte (molecular compound - neither acid nor base) 4.9 Ionic compounds, strong acids, and strong bases (metal hydroxides) are strong electrolytes (completely broken up into ions of the compound). Weak acids and weak bases are weak electrolytes. Molecular substances other than acids or bases are nonelectrolytes.
    [Show full text]
  • Lecture 6 Outline
    Lecture 6 Classes of Chemical Reactions Lecture 6 Outline 6.1 The Role of Water as a Solvent 6.2 Precipitation Reactions 6.3 Acid-Base Reactions 1 Electron distribution in molecules of H2 and H2O The electrical conductivity of ionic solutions 2 The dissolution of an ionic compound A substance that conducts a current when dissolved in water is an electrolyte. Ionic compounds are strong electrolytes Sample Problem: Determining Moles of Ions in Aqueous Ionic Solutions PROBLEM: How many moles of each ion are in the following solutions? (a) 5.0 mol of ammonium sulfate dissolved in water (b) 78.5g of cesium bromide dissolved in water (c) 7.42x1022 formula units of copper(II) nitrate dissolved in water (d) 35mL of 0.84M zinc chloride n = m/M c = n/V + 2- SOLUTION: (a) (NH4)2SO4(s) 2NH4 (aq) + SO4 (aq) 5.0mol (NH ) SO + 2- 4 2 4 10.mol NH4 5.0mol SO4 3 Sample Problem Determining Moles of Ions in Aqueous Ionic continued Solutions (b) CsBr(s) Cs+(aq) + Br-(aq) – + CsBr: 78.5g/ 212.8g/mol = 0.369mol CsBr = 0.369mol Br = 0.369mol Cs 2+ - (c) Cu(NO3)2(s) Cu (aq) + 2NO3 (aq) 7.42x1022 formula = 0.123mol Cu2+ = 0.123mol Cu(NO ) 3 2 = 0.246mol NO – 6.022x1023 formula units 3 2+ - (d) ZnCl2(aq) Zn (aq) + 2Cl (aq) n = c V -2 ZnCl2 0.035L x0.84mol/L = 2.9x110 mol ZnCl2 = 2.9x110-2mol Zn2+ = 5.8x110-2mol Cl- Precipitation Reactions 4 Precipitation Reactions Precipitate – insoluble solid that separates from solution molecular Pb(NO ) (aq) + 2NaI (aq) PbI (s) + 2NaNO (aq) equation 3 2 2 3 precipitate ionic 2+ - + - + - Pb + 2NO3 + 2Na + 2I PbI2 (s) + 2Na + 2NO3 equation net 2+ - ionic equation Pb + 2I PbI2 (s) + - Na and NO3 are spectator ions Sample Problem Determining the Molarity of H+ Ions in Aqueous Solutions of Acids PROBLEM: Nitric acid is a major chemical in the fertilizer and explosives industries.
    [Show full text]
  • Acids, Bases and Neutralization Reactions ACIDS Many Acids and Bases Are Industrial and Household Substances and Some Are Important Components of Biological fluids
    Reactions in aqueous solutions Acids, Bases and Neutralization reactions ACIDS Many acids and bases are industrial and household substances and some are important components of biological fluids. Hydrochloric acid (HCl), for example, is an important industrial chemical124 CHAPTER 4andReactions the in Aqueous Solution main constituent of gastric juice in your stomach. equations for precipitation reactions, the anions and cations appear to exchange partners. Thus, 2+ 2- + - we put Ca and CO3 together to give CaCO3 and Na and Cl together to give NaCl. Accord- ing to the solubility guidelines in Table 4.1, CaCO3 is insoluble and NaCl is soluble. The balanced molecular equation is CaCl2 aq + Na2CO3 aq ¡ CaCO3 s + 2 NaCl aq . In a complete ionic equation,1 2 only dissolved1 2 strong electrolytes1 2 (such as1 soluble2 ionic com- Acids and bases are also common electrolytes pounds) are written as separate ions. As the (aq) designations remind us, CaCl2,Na2CO3,and NaCl are all dissolved in the solution. Furthermore, they are all strong electrolytes. CaCO3 is an ionic compound, but it is not soluble. We do not write the formula of any insoluble compound as its component ions. Thus, the complete ionic equation is į FIGURE 4.5 Vinegar and lemon juice 2+ - + 2- are common household acids. Ammonia Ca aq + 2 Cl aq + 2 Na aq + CO3 aq ¡ and baking soda (sodium bicarbonate) + - CaCO3 s + 2 Na aq + 2 Cl aq are common household bases. 1 2 1 2 1 2 1 2 - + Acids are substances that ionize in aqueous solutions to Cl and Na are spectator ions.
    [Show full text]
  • Three Major Classes of Chemical Reactions
    Chapter 4 Three Major Classes of Chemical Reactions 4-1 The Major Classes of Chemical Reactions 4.1 The Role of Water as a Solvent 4.2 Writing Equations for Aqueous Ionic Reactions 4.3 Precipitation Reactions 4.4 Acid-Base Reactions 4.5 Oxidation-Reduction (Redox) Reactions 4.6 Elements in Redox Reactions 4.7 Reaction Reversibility and the Equilibrium State 4-2 Water as a Solvent • Water is a polar molecule – since it has uneven electron distribution – and a bent molecular shape. • Water readily dissolves a variety of substances. • Water interacts strongly with its solutes and often plays an active role in aqueous reactions. 4-3 Figure 4.1 Electron distribution in molecules of H2 and H2O. A. Electron charge distribution in H2 is symmetrical. B. Electron charge distribution in H2O is asymmetrical. C. Each bond in H2O is polar. D. The whole H2O molecule is polar. 4-4 Figure 4.2 An ionic compound dissolving in water. 4-5 Figure 4.3 The electrical conductivity of ionic solutions. 4-6 Sample Problem 4.1 Using Molecular Scenes to Depict an Ionic Compound in Aqueous Solution PROBLEM: The beakers shown below contain aqueous solutions of the strong electrolyte potassium sulfate. (a) Which beaker best represents the compound in solution? (H2O molecules are not shown). (b) If each particle represents 0.10 mol, what is the total number of particles in solution? 4-7 Sample Problem 4.1 PLAN: (a) Determine the formula and write and equation for the dissociation of 1 mol of compound. Potassium sulfate is a strong electrolyte; it therefore dissociates completely in solution.
    [Show full text]
  • Electrolytes-Wkst-KE
    Electrolytes Worksheet Name: _______KEY_________ 1. Substances are classified as either soluble or insoluble in water. When a substance dissolve in water it forms a(n) aqueous solution. 2. A substance that does not dissolve in water is called insoluble. 3. A water soluble substance is classified as either an electrolyte or a non-electrolyte. 4. An electrolyte is a substance whose aqueous solution conducts electricity. 5. A substance whose aqueous solution does not conduct electricity is called a non-electrolyte. 6. In order for a solution to conduct electricity, it must contain ions. 7. If we were able to examine an aqueous solution of table salt, NaCl (aq), at the molecular level, we would see individual sodium and chloride ions, Na+ and Cl-, hydrated. That is they are separated, dispersed and surrounded by water molecules. Therefore, table salt is classified as a(n) electrolyte. 8. If we were able to examine an aqueous solution of table sugar at the molecular level, we would see the individual sugar molecules hydrated. That is they are intact, dispersed and surrounded by water molecules. Therefore, table sugar is classified as a(n) non-electrolyte. 9. Electrolytes break into ions as they dissolve in water. A compound that breaks entirely into ions as it dissolves in water is classified as strong electrolyte. A compound that breaks partially into ions as it dissolves in water is classified as a weak electrolyte. 10. At the same molar concentration, a strong electrolyte is a much better conductor than a weak electrolyte. 11. Compounds that are classified as strong electrolytes and therefore break entirely into ions in dilute aqueous solutions are: strong acids, strong bases, and soluble salts.
    [Show full text]