Question

3. 10 points. Calculate the amounts (kg, 100% basis) of H2SO4 and NaOH required in a dual bed ion exchange system to remove the calcium and chloride ions in 1000 m3 of water containing 100 mg CaCl2/L. Assume 100 % efficiency of chemical usage (which is not correct). Hint: use one mole of H2SO4 per mole of Ca, and one mole of NaOH per mole of Cl 4. 5 points. Using Eq. 4-17 (shown below) calculate the dose of calcium hydroxide in mg Ca(0H)2/L needed to remove the magnesium in a water containing 124 mg MgCl2/L. Ignore subsequent soda ash requirements to remove the added calcium Hint: use one mole of lime per mole of magnesium. Note: this is non-carbonate hardness 5. 5 points. Briefly explain the formation of "soap scum" in terms of the chemical elements in hard water and "natural" soap. Cа2* + Na,CO3 Eq 4-16 СаСОз(s) + 2 Na* Mg2+ + Ca(ОН)2 Mg(ОН)2(s) + Са2* Eq 4-17

Answer 1

Given tha dmoutb water = 1oo L Amound b C Cl= Caon2 (£ Cacb t equdvadut 952113mo mol mgcl2 avo ab aker Gntaln Cocla 95.219 in looo L 95.211 g5211 mg 24mg moj tmmo - 95 24x 130 mmo= mmol eb mgcl2 Molealar ot at Caci2 mmol uo 35.5x2= 1M 5.21 2 mol So He ameunt al Caon), heeded is - 1 mo 1-30 mm x molealarot eb Ca(Un g&320xlog So We amount ct CoM2ered to ieme ve j24 mg al Mgclz i 0.og6 So th nu ob Ca2t \n lwoL o.Sau me are Sedium or bottaium Salt of Stedric odd which are but cohan the wader Gnten Ca nma ma co2 en Sodlum ton Ca2tHSOu Saluble in ater th Ha orm et Gbn Ca Co or Ca SOutt 2c 2N4 and mg oHch ere insoluole Sodiu m steretle get eplqed by n Loater d o Coab saup 2Ne C 20He G22ci2Ngont Haso CgH35 Cok Soluble in coker Hsou Teured ogomol Naon eaulred = 18 mol = 98 xo goo 38-29 Soluble In toatey (C19 Mss Coo a* +CaCo 2.09 an2Cia HssEoONa HesOu Tea {n uader 88-29 a o882 Cs SeanneCI netho.07 20 CamScanner (C35 C t g. Tm Soluble in Deder