Question

12 – A solution of 0.060 M NaF (75 mL) is mixed with 0.15 M Sr(NO3)2 (25 mL). Calculate the concentrations of each ion after equilibrium is achieved given Ksp for SrF2 = 2.0 x 10-10.Hint: The ion exchange reaction to produce SrF2 can be considered to go to completion before equilibrium is reestablished starting from the products, much as we’ve done for titration calculations at the equivalence point

13 – a) Calculate the molar solubility of hydroxyapatite given Ksp = 2 x 10-59.b) Calculate the molar solubility of hydroxyapatite in a buffered solution of pH 4.0.You’ll need to find the formula for hydroxyapatite and its solvation reaction in order to write the equilibrium constant expression.

Answer 1

mmoles NaF Ciniran) 0-660m x 75ml 4.5 mmoles - SvF + 2Nang SKING + 2NaF ner reaction to sut2 + z Sufis from equation 2 mole NOR give Imole SvF 4-5 mmole Nar ? mules SVE Z2 4.5 mmoles Produced 22-25 mmoles 22-25 x 103 moles mmoles Sung? 2 0-15m x 25ml 3-75 mmoles, 3.75 mmoles can give 3.70 mmole suh moles So and SVF NaF moles Produce from Naf is less acts as limiting reactants SvĘ produced 22-25 x 10 moles. Here so wat and no acts the concentration Intrally in final concentration. as spectata las mixture (nat) 2 moles waf 4.5 mmoles. Tural volume 100 me 2 10.045 m 2 xmoles sv (Ng z 2x3-75mmoles 100ml Total volume 20.075m Cno- a

= mmoles Sh produced mmoles reacts Esrt2) Total ve reacts immules - mmoles Total blume 3-75 mmdes - 2-25 mmules luomi focom SIS ² sut2 + 2F Car 0.015mo ts the o-alsts tas (neglest saa ksp lest) Ksp & [set 2) (F)? or 2000 to 2 Lo-osm] [o? + 2015 caa 25 = [ 2ooool154 m 2 0.00012 m. hydroxyapatite cao (Pou) Cons & 10 cat? +610 3 caw caw solubinty s los GS Ksp 2 [cate) ( pq, 3) Cort? 2x1059 - [10s) (65)* [25) 2. 2x 1654 2 186,624x15 58 - 5 18 2x1059 Lis6,624 xido =) s 7.77 x 10s moles so solubinry of hydroxy apatite as 8x105 moles molar

са (Po4 ) (ол) = 10 cott 16 Розон lus as loto pH zu means pon a 14-4 = 10 Con a 100 m. . kop 2 Closlo cose cloto? 2 2x1059 a 10 x 51 x 46,656.4 10 20 2) s. 219 22 10 59 46,656x16 10 S a 0.000462 m مارک نه