hourglass ea lik'hemik'hale
Boitšoaro ba oache ke liphetoho tseo phello ea tsona (mohlala, phetoho ea 'mala) e sa hlaheng hang-hang, empa ka mor'a nako e itseng ka mor'a ho kopanya li-reagents. Hape ho na le maikutlo a u lumellang hore u bone sephetho ka makhetlo a 'maloa. Ka papiso le "chemical clock" ba ka bitsoa "chemical hourglass". Li-reagents tsa e 'ngoe ea liteko ha li thata ho li fumana.
Bakeng sa teko re tla sebelisa magnesium oxide, MgO, 3-4% hydrochloric acid, HClaq (e hloekisitsoeng ka metsi 1: 9) kapa asene ea lijo (6-10% tharollo ea acetic acid CH).3COOH). Haeba re se na magnesium oxide, lithethefatsi tsa ho loantša acidity le ho otloa ke pelo li ka e nkela sebaka ka katleho - e 'ngoe ea metsoako ke magnesium hydroxide (MgO e fetoloa motsoako ona tlas'a maemo a karabelo).
E ikarabella bakeng sa phetoho ea 'mala nakong ea karabelo bromothymol e putsoa - letšoao le fetoha mosehla ka tharollo ea acidic le hoo e batlang e le putsoa.
Bakeng sa khalase ea 100 cm3 tšela likhabapo tse 1-2 tsa magnesium oxide (senepe 1) kapa tšela ka 10 cm3 tokiso e nang le magnesium hydroxide. Ebe u eketsa 20-30 cm.3 metsi (senepe 2) 'me u kenye marotholi a seng makae a pontšo (senepe 3). Kopanya litaba tsa khalase e putsoa (senepe 4), ebe o tšela cm e seng mekae3 tharollo ea acid (senepe 5). Motsoako o ka khalaseng o fetoha mosehla (senepe 6), empa ka mor'a nakoana e fetoha e putsoa hape (senepe 7). Ka ho eketsa karolo e 'ngoe ea tharollo ea asiti, re boetse re bona phetoho ea' mala (foto 8 le 9). Potoloho e ka phetoa ka makhetlo a 'maloa.
Maikutlo a latelang a etsahetse ka khalaseng:
1. Magnesium oxide e kopana le metsi ho etsa hydroxide ea tšepe ena:
MgO + N2O → Mg (OH)2
Motsoako o hlahisoang ha o qhibilihe hantle metsing (hoo e ka bang 0,01 g ka 1 dm3), empa ke motheo o matla 'me mahloriso a li-ion hydroxide a lekane ho mebala letšoao.
2. Karabelo ea magnesium hydroxide le tlatsetso ea hydrochloric acid:
Mg(OH)2 + 2HCl → MgCl2 + lihora tse 22O
e lebisa ho se nke lehlakore ha Mg (OH) eohle e qhibilihisitsoeng metsing2. Ho feta HClaq e fetola tikoloho hore e be acidic, eo re e bonang ka 'mala oa letšoao o fetoha mosehla.
3. Karolo e 'ngoe ea magnesium oxide e kopana le metsi (equation 1.'me e fokotsa acid e feteletseng (equation 2.). Tharollo e fetoha alkaline hape 'me pontšo e fetoha e putsoa. Potoloho ea pheta.
Ho fetola phihlelo ho kenyelletsa ho fetola letšoao le sebelisitsoeng, ho fella ka liphello tse fapaneng tsa mebala. Tekong ea bobeli, ho e-na le bromothymol blue, re tla sebelisa phenolphthalein (e se nang mebala ka tharollo e nang le asiti, krimsone ka tharollo ea alkaline). Re lokisetsa ho emisoa ha magnesium oxide metsing (seo ho thoeng ke lebese la magnesia), joalo ka tekong e fetileng. Kenya marotholi a seng makae a tharollo ea phenolphthalein (senepe 10) le ho hlohlelletsa litaba tsa khalase. Ka mor'a ho eketsa cm e seng mekae.3 asiti ea hydrochloric (senepe 11) motsoako o fetoha mmala (senepe 12). Ho hlohlelletsa litaba ka linako tsohle, u ka bona ka tsela e fapaneng: ho fetoha ha 'mala ho pinki,' me ka mor'a ho eketsa karolo ea asiti, ho fifala ha lintho tse ka har'a sekepe (setšoantšo 13, 14, 15).
Liphetoho li tsoela pele ka tsela e tšoanang le ea teko ea pele. Ka lehlakoreng le leng, ho sebelisa pontšo e fapaneng ho fella ka liphello tse fapaneng tsa mebala. Hoo e ka bang pH indicator efe kapa efe e ka sebelisoa tekong.
Chemical Hourglass, Karolo ea I:
The Chemical Hourglass, Karolo ea I
Chemical Hourglass, Karolo ea II:
Chemical Hourglass Karolo ea XNUMX
