Ua ntej tshaj plaws, cia peb kawm seb vim li cas nws thiaj li muaj teeb meem thaum dej hnyav dhau. Nws cov dej tsis tu ncua entails cov tsos ntawm pob zeb nyob rau hauv lub excretory system. Kev siv nws rau da dej lossis ntxhua khaub ncaws feem ntau ua rau tawv nqaij khaus, tshwj xeeb tshaj yog rau cov menyuam yaus. Tsis tas li ntawd, nws tuaj yeem tsim qee yam tsis yooj yim hauv lub neej niaj hnub: hlau ntsev (calcium thiab magnesium), uas yog lub luag haujlwm rau dej hardness, tuaj yeem tsim cov tshuaj tshwj xeeb (insoluble) nrog fatty acids uas muaj hauv xab npum.
Cia peb sim:
- Muab dej rau hauv lub khob kom txog 40 lub cim.
- Ntxiv tag nrho 0.2 m ntawm calcium chloride tov los ntawm lub vial.
- Nqa ib lub qhov cub thiab tso lub tswm ciab rau nws. Tom qab ntawd tshem koj cov hnab looj tes tiv thaiv thiab teeb lub tswm ciab. Nruab cov nplaim diffuser rau ntawm qhov cub.
- Muab lub khob rau ntawm cov nplaim hluav taws. Thov tos 15 feeb.
- Pour tag nrho 0.3M sodium bicarbonate tov los ntawm vial.
- Tom qab ntawd, cov dej hauv lub khob yuav pos huab.
Dab tsi yog qhov nyuaj ntawm dej?
Ib ntusthiab tsis tu ncua dej hardness. Dab tsi yog qhov tsis tu ncua?
Qhov no yog ib qho txiaj ntsig zoo li no, qhia txog cov ntsev ntawm ntau yam hlau yaj hauv dej, xws li calcium, manganese, hlau. Ib ntus hardness (uas tuaj yeem muab rho tawm) thiab ruaj khov hardness. Lub sijhawm ib ntus yog vim calcium thiab magnesium bicarbonate, thiab qhov chaw mus tas li yog vim lawv cov sulfates thiab chlorides (CaCl 2 thiab MgCl2). Peb tuaj yeem xaus tias cov dej tawv yog ib qho uas muaj ntau cov ntsev ntsev tib lub sijhawm.
Thaum peb ntxiv calcium chloride rau nws, peb ua kom nws cov tawv tawv. Raws li tau hais los saum no, CaCl2 ua rau tsis muaj carbonate hardness nyob rau hauv dej. Thiab ib feem ntawm peb qhov kev sim ua kom pom qhov tseeb no: thaum npau taws, tsis muaj nag lossis daus tshwm sim ntawm phab ntsa.
Ntxiv cov sodium bicarbonate NaHCO3 ua rau tsim cov calcium bicarbonate hauv cov tshuaj: 2 NaHCO3 + CaCl 2 =Ca (HCO3)2 + 2NaCl, thiab vim yog tsim ntawm Ca (HCO3)2, lub hardness ntawm peb cov dej dhau los ua ib ntus - tam sim no nws tuaj yeem raug tshem tawm los ntawm boiling.
Vim li cas nplai thiaj tsim thiab yuav tshem nws li cas
Scale (los yog txiv qaub nplai) yog ib qho calcium carbonate insoluble uas precipitates thaum lub sij hawm thermal decomposition ntawm calcium bicarbonate. Txawm hais tias cov tuab grey nplai txheej tsis ua rau cov zaub mov zoo nkauj, nws tsis muaj mob. Tsis tas li ntawd, nws tuaj yeem tshem tawm qhov nyuaj ntawm cov kais dej. Tsis tas li ntawd, nplai tuaj yeem raug tshem tawm yooj yim los ntawm teapots thiab pots los ntawm kev ntxuav lawv nrogcitric acid daws.
yuav ua li cas thiaj muag dej
Dej, uas muaj me me ntawm cov ntsev ntsev, yog mos. Thiab cov txheej txheem hardness extraction softens nws. Txoj kev yooj yim tshaj plaws kom soften, raws li qhia hauv peb qhov kev sim, yog boiling. Thaum rhuab, calcium thiab magnesium bicarbonates raug thermal decomposition. Cov txheej txheem no tsuas yog tshem tawm ib ntus (carbonate) hardness (cov dej tas mus li tuaj yeem raug tshem tawm los ntawm lwm txoj kev). Lub hardness tsis tu ncua yog khaws cia: dej saturated nrog calcium chloride CaCl2 tawm tsis muaj residue thaum boiled. Distillation yog ze ze rau qhov kev ua no. Thaum lub sij hawm distillation txheej txheem, cov kua evaporated condenses rau ntawm qhov chaw txias thiab yog li sau nyob rau hauv daim ntawv ntawm cov tee dej. Dej purified li no hu ua distilled. Nws tsis haum rau haus, vim nws leaches minerals los ntawm lub cev. Txawm li cas los xij, nws tau siv dav hauv kev tshawb fawb thiab kev lag luam.
Lwm txoj hauv kev kom soften yog siv cov tshuaj reagents. Lawv hloov magnesium thiab calcium ions mus rau ib daim ntawv uas tsis yaj los ntawm kev ntxiv qee yam tshuaj, xws li calcium hydroxide (ib txoj kev hu ua txiv qaub softening). Zoo li boiling, softening txiv qaub tsuas yog tshem tawm carbonate hardness.
Tshem tawm dej khov mus tas li
txhawm rau txhawm rau rho tawm qhov nyuaj (tsis yog carbonate) nyuaj, xav tau kev sib sib zog nqus dej, yog li lawv siv carbonate ntxiv rau slaked txiv qaubsodium.
Rau qhov kev tshem tawm cov hlau ions tau zoo dua, " phom loj" - sodium phosphate yog siv:
Na3PO4:CA3 3Ca2+ + 2Na3PO4 → (PO4)2↓ + 6Na+
3Mg2+ + 2Na3PO4=Mg3(PO4)2=+ 6Na+.
Qhov tsis zoo ntawm txoj kev softening no yog qhov yuav tsum tau txhaj cov tshuaj reagents muab rau peb kom raug. Hauv kev lag luam, thev naus laus zis ntawm dej softening nrog ion pauv resins feem ntau yog siv. Cov kws tshaj lij hla dej los ntawm lub lim dej uas khaws cov hlau ions (calcium, manganese, hlau, magnesium). Cov "raug" cov khoom no tau hloov los ntawm cov poov tshuaj, sodium, lossis hydrogen H + ions tso tawm rau hauv cov tshuaj. Txoj kev no kuj tseem siv tau thaum cov dej tsis tu ncua thab koj.
Cov lus xaus: qhov twg zoo dua?
Cov dej twg zoo dua rau koj - tawv lossis mos? Cov lus teb yog yooj yim: txhua yam yog zoo nyob rau hauv moderation. Qhov kev xaiv zoo tshaj plaws rau kev siv hauv tsev niaj hnub yog dej ntawm qhov nruab nrab hardness, uas muaj me me ntawm cov khoom tsis zoo. Txoj kev sib npaug yog ib txwm yog txoj hauv kev rau kev sib haum xeeb.