ACIDS AND BASES Label the following properties as “A” for acid, “B” for base or “AB” for acids and bases Tastes bitter Increases [H+] Corrosive Tastes sour Increase [OH-] Electrolyte Neutralizes HCl Proton acceptor Proton donor Neutralizes NaOH Contains H+ ions Contains OH- ions Feels slippery Turns litmus red Turns litmus blue SVANTE ARRHENIUS NEUTRALIZATION acids and bases: EQUATION: BRONSTED-LOWRY acids and bases: Match these substances with their chemical formulas, then write as “A” for acid, “B” for base where applicable ____1. Table salt ____2. Water ____3. Stomach acid ____4. Sugar ____5. Limewater ____6. Household ammonia ____7. Hydrogen peroxide ____8. Chalk ____9. Drain cleaner (lye) ____10. Vinegar ____11. Battery acid ____12. Citric acid a) H2O2 b) CaCO3 c) HC2H3O2 d) H3C6H5O7 e) H2O f) NH3 g) C12H22O11 i) Ca(OH)2 j) H2SO4 k) NaOH l) NaCl m) HCl ELECTROLYTES NAMING ACIDS “ate” becomes “_____ic acid” “ite” becomes “_____ous acid” “ide” becomes “hydro_____ic acid Ion name chloride sulfide cyanide iodide nitrate chlorate phosphate sulphate sulfite chlorite nitrite perchlorate hypochlorite permanganate periodate phosphite carbonate bromate thiosulfate iodate bicarbonate* hydroxide* oxide* peroxide* * = be careful Ion formula in sulfur compounds, add “ur” in phosphorus compounds, add “or” Acid Formula Acid Name A C I D S A N D B A S E S C A L C U L A T I O N S What volume of 0.15M sodium hydroxide solution is required to neutralize 275mL of a 0.40 M hydrochloric acid solution? What is the concentration of 20.0 ml of sulphuric acid neutralized by 65 ml of 0.25 M lithium hydroxide solution? ACIDS AND BASES CALCULATIONS (NEUTRALIZATION QUESTIONS) 1) If 35 ml of 0.75M HCl (aq) are neutralized by 85 ml of NaOH (aq), determine the concentration of the base. 2) What volume of 0.620M phosphoric acid will neutralize 75 ml of 0.250 M KOH (aq)? 3) What volume of 0.150 M sulphuric acid will neutralize 45 ml of 0.0800M aluminum hydroxide solution? One more PRECIPITATION QUESTION… 4) Determine the ion concentrations following the precipitation resulting from the combination of 150. ml of 0.45 M aluminum sulphate solution and 200. ml of 0.60 M strontium hydroxide solution. ACIDS AND BASES KEY Label the following properties as “A” for acid, “B” for base or “AB” for acids and bases Tastes bitter Increases [H+] Corrosive B A AB A Tastes sour B Increase [OH-] AB Electrolyte B Neutralizes HCl B Proton acceptor A Proton donor A Neutralizes NaOH A Contains H+ ions B Contains OH- ions B Feels slippery A Turns litmus red B Turns litmus blue SVANTE ARRHENIUS acids and • acids produce H+ ions in aqueous solutions • bases produce OH- ions in aqueous solutions NEUTRALIZATION EQUATION: ACID + BASE SALT + WATER HA + BOH BA + HOH BRONSTED-LOWRY • acids are proton donors • bases are proton acceptors HNO3 (aq) + H2O NO3-(aq) + H3O+(aq) NH3 (aq) + H2O NH4+(aq) + OH-(aq) acids and bases: bases: Match these substances with their chemical formulas, then write as “A” for acid, “B” for base where applicable L 1. Table salt a) H2O2 b) CaCO3 E 2. Water c) HC2H3O2 M 3. Stomach acid A d) H3C6H5O7 G 4. Sugar e) H2O I 5. Limewater B f) NH3 g) C12H22O11 F 6. Household ammonia B i) Ca(OH)2 A 7. Hydrogen peroxide A j) H2SO4 B 8. Chalk k) NaOH K 9. Drain cleaner (lye) B l) NaCl C 10. Vinegar A m) HCl J 11. Battery acid A D 12. Citric acid A ELECTROLYTES An electrolyte is any substance that will conduct electricity when dissolved in water, due to the presence of free ions. EXAMPLES: + − Dissociation of salts: NaCl(s) → Na (aq) + Cl (aq) Strong acids and bases are electrolytes: HCl (aq) + H2O Cl-(aq) + H3O+(aq) NaOH (aq) Na+(aq) + OH-(aq) More on this in Chem 12 NAMING “ate” becomes “_____ic acid” “ite” becomes “_____ous acid” “ide” becomes “hydro_____ic acid Ion Ion name formula chloride Clsulfide S2cyanide CNiodide Initrate NO3chlorate ClO3phosphate PO43sulphate SO42sulfite SO32chlorite ClO2nitrite NO2perchlorate ClO4hypochlorite ClOpermanganate MnO4periodate IO4phosphite PO33carbonate CO32bromate BrO3thiosulphate S2O32iodate IO3bicarbonate* HCO3hydroxide* OHoxide* O2peroxide* O22* = be careful ACIDS KEY in sulfur compounds, add “ur” in phosphorus compounds, add “or” Acid Acid Name Formula HCl hydrochloric acid H2S hydrosulphuric acid HCN hydrocyanic acid HI hydroiodic acid HNO3 nitric acid HClO3 chloric acid H3PO4 phosphoric acid H2SO4 sulphuric acid H2SO3 sulphurous acid HClO2 chlorous acid HNO2 nitrous acid HClO4 perchloric acid HClO hypochlorous acid HMnO4 permanganic acid HIO4periodic acid H3PO3 phosphorous acid H2CO3 carbonic acid HBrO3 bromic acid H2S2O3 thiosulphuric acid HIO3iodic acid H2CO3 carbonic acid HOH water H2O water H2O2 hydrogen peroxide ACIDS AND BASES CALCULATIONS (NEUTRALIZATION QUESTIONS) KEY 1) If 35 ml of 0.75M HCl (aq) are neutralized by 85 ml of NaOH (aq), determine the concentration of the base. HCl (aq) (0.75 + NaOH(aq) H2O(l) + NaCl(aq) )(0.035L) = 2.6X10-2 moles 2.6X10-2 moles In any neutralization, Moles H+(aq) = moles OH-(aq) since H+(aq) + OH-(aq) H2O(l) Think of this water formation equation as the net equation for a neutralization reaction. The ultimate goal is the H +(aq) from the acid and the OH-(aq) from the base come together to form water, neutralizing the acid and base. The other product is not represented in the net equation since Na+(aq) + Cl-(aq) NaCl(aq) should really be written as Na+(aq) + Cl-(aq) Na+(aq) + Cl-(aq) since the ions in the salt (ionic compound) are completely dissociated in aqueous solution. If moles of acid = moles of base = 2.6X10-2 moles Then we could complete this question by: [NaOH] = = 0.31 M NaOH Another way to consider completing this question is: MaVa = MbVb (0.75 )(0.035L) = Mb (0.085L) Mb = 0.31 M NaOH NEUTRALIZATION QUESTIONS KEY page two 2) What volume of 0.620M phosphoric acid will neutralize 75 ml of 0.250 M KOH (aq)? BE CAREFUL HERE! First consider the balanced neutralization reaction: H3PO4(aq) + 3KOH(aq) (0.075L)(0.250 0.00625 moles 3H2O(l) + K3PO4 (aq) )= 0.01875 moles divide by 3 Then we can determine the volume of H3PO4(aq) : = X 0.00625moles = 0.01008 L = 10.08 mL Due to SF we must report 10. mL NOTE! Another way to consider doing this question is recognizing that when H3PO4 and KOH react, the H+ and OH- are in a 3:1 ratio and therefore before we begin this method: MaVa = MbVb We must use 3 times the molarity for H3PO4 (0.620M X 3), in order to have it equal the RS of the equation, MbVb: (1.86 )Va = (0.250M) (0.075L) Va= 10.08 mL NEUTRALIZATION QUESTIONS KEY page three 3) What volume of 0.150 M sulphuric acid will neutralize 45 ml of 0.0800M aluminum hydroxide solution? 3H2SO4(aq) + 2Al(OH)3(aq) 6H2O(l) + Al2(SO4)3 (aq) Consider looking at the question in the following way. Consider the dissociation of the acid and the base in aqueous solution: H2SO4(aq) 2H+(aq) + SO4-2(aq) 0.150M 0.300M and Al(OH)3(aq) Al+3(aq) + 3OH-(aq) 0.0800M 0.240M Then we can use MaVa = MbVb Keeping in mind that MaVa = moles H+(aq) and Mb Vb = moles OH-(aq) SO: (0.300M) Va = (0.240 M)(45 ml) Va = 36 mL Note the variety of ways in which we can arrive at the correct solutions for these types of problems!!! You need to develop this flexibility in finding these solutions in order to survive the 8 to 10 week acid and base unit in Chemistry 12!!!!!!!!! One more PRECIPITATION QUESTION… KEY page four 4) Determine the ion concentrations following the precipitation resulting from the combination of 150. ml of 0.45 M aluminum sulphate solution and 200. ml of 0.60 M strontium hydroxide solution. DILUTION Al(SO4)3(aq) Sr(OH)2(aq) = 0.19M = 0.34M Note that I am using the TOTAL final volume of 350 mL in my M1V1 = M2V2 dilution calculation. M2 = DISSOCIATION Al2(SO4)3(aq) 2Al 0.19M +3 0.38M (aq) + 3SO4-2(aq) 0.57M Sr(OH)2(aq) Sr+2aq) + 2OH-(aq) 0.34M 0.34M 0.68M PRECIPITATION Possible precipitates: Al(OH)3 and SrSO4 BOTH ARE POSSIBLE PRECIPITATES! Al+3(aq) 0.38M 0.23M + 3OH-(aq) Al(OH)3(s) Sr+2aq) 1.14M 0.68M 0.34M 0.57M + SO4-2aq) 0.34M 0.57M SrSO4(s) [Al+3] = 0.38 (avail) – 0.23 M (reacted) = 0.15 M (excess) [OH-] = 0 M (limiting reagent; totally used up in precipitate formation) [Sr+2]= 0 M (limiting reagent; totally used up in precipitate formation) [SO4-2] = 0.57 (avail) – 0.34 M (reacted) = 0.123 M (excess)
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