Question

Design a buffer that has a pH of 5.85 using one of the weak base/conjugate acid systems shown below. Weak Base Kb pka 10.62 CH3NH2 C6H1503N C3H5N 4.2x10-4 5.9x10-7 1.5*10-9 Conjugate Acid CH3NH2+ CGH1503NH+ CsH5NH ка 2.4x10-11 1.7*10-8 6.7x10-6 7.77 5.17 How many grams of the bromide salt of the conjugate acid must be combined with how many grams of the weak base, to produce 1.00 L of a buffer that is 1.00 M in the weak base? grams bromide salt of conjugate acid = grams weak base =

Answer 1

knaw daat f base hehdessan-Kassel balch euaton ven by Pol pkb t la CBrt CBJ uate Pk -l0g Ckb kp base dssouå tfon Constant weap base EtConjugate ac B=weak bage gien ph 5.85 POH- 14- PH 14 585 8-15 . 2x10 foy CMNH23 NH, ko PK 3.376750 NH k57 xio for 4503N Pky 6. 221/4711 C5MN CN k15xi01 PKb 22 31087 fox to Pkbalua The PoK value C815) close 8231 0871f buffes to wak best)

CstsNuNt Thug, the bu ffe Sskm s gfhen voume buffe oOL Molasit weak boge (55N)- 100M B)=M Thug, CA)= Substrtrfing the Valueg eqn G we haue 8-8239 0811 + log But 8.15

৪-15 - ৪-৪23৭०8+4 lo Bo loq CBrc] - ० - ০. 673१0g74 -০. 6 ৭3१०४7१ lo lo०০ (Brr) Cert ০. २॥ 88০ ८32 ০. २ ।। 88০ १2M [ N Thus > ५6Nk +B Since क%NB [८t Nr) = [५wea) 6 a॥ १8० 632 M

Molan?ty of 5 NHBTX Valume fbufe Moles 545NMBY a. al 880632 mal x 100 0.21880632 ma Molaa maIs Я5H5 NИBY (AHomPc massc t 5X Atom?c massg 1T x Atamfc massg T I Atom?c mass o B) (hx 12.0107mmol t 500784mol t x 14. 0067mol t Ixo0784 3(mol + x 71.90 al) -t60. o121 3mol Thug Mass C55 NH BY Moles CNHAY X Halas mass a 55 AHBY o.all 880 632 hal x to oli2t =33 1032 827 a 33-93

Mass e5K5N Holes o 5N X Molas mass 5K5N Molait 5HNx Voume hufe 5N Molas mas 100M 100 L) x 79.0111 mol 79.694 79.0914 71.19 B Henderson- Kasel balch equaten 21 (CA1 Ph= Pkat log CHA Constant dis so ca tfen ka acd 20 xi01 Cven) log Cka) log 7. 20xio 3.1426675 Pka = 2. a1o auen PM reak acra MA bage CA1 onyagte CHA Ceak acrd

ven: Volume buffe 00L HF (HA) 0-137M Molanity Sine voume Same f boit HF and F we can Sad feat C3 CHF Moleg e Moles MF Moles o F2L Mole gL Moles X Moles HF Moles F Moleg hF Malarib RFX Voume g saluton a 137 oa a oo HF Moles 0. 274 ma Substr tufing the vatuag 1h theequatfon we haue PHPKA t lo (Molep o Moleg nA (Moles 3.14 215 g 0 34mol

log (Mole o 3.1426 675 leg CMoles o. 932 675 - log (o-274) - O. 132665 -0.5224143 og CMaleg g -o.932 6675-0.562249437 lag Moles o . 49491691 l0a CMoles -4194 Moles F O 0319950 69 Sine, KA ktt F- KF Moley Males 0. 031995o697 KF- 58.0167mol Molaa mass KF Moleg KAxMalag Mass -o.031995O697X58-09 3 M ags t869