sinadarai hourglass
Abubuwan halayen sa'o'i sune canje-canje wanda tasirinsa (misali, canjin launi) ba ya bayyana nan da nan, amma bayan ɗan lokaci bayan haɗuwa da reagents. Hakanan akwai halayen da ke ba ku damar ganin sakamakon sau da yawa. Ta hanyar kwatankwacin "Agogon sinadarai" ana iya kiran su "chemical hourglass". Reagents na ɗaya daga cikin gwaje-gwajen ba su da wahala a samu.
Don gwajin za mu yi amfani da magnesium oxide, MgO, 3-4% hydrochloric acid, HCl.aq (mai mayar da hankali acid, diluted da ruwa 1:9) ko abinci vinegar (6-10% bayani na acetic acid CH3COOH). Idan ba mu da magnesium oxide, kwayoyi don magance acidity da ƙwannafi za su sami nasarar maye gurbinsa - daya daga cikin sinadaran shine magnesium hydroxide (MgO ya juya cikin wannan fili a ƙarƙashin yanayin amsawa).
Alhaki don canza launi a lokacin amsawa bromthymol blue - mai nuna alama ya juya rawaya a cikin maganin acidic kuma kusan shuɗi.
Don gilashin 100 cm3 zuba 1-2 teaspoons na magnesium oxide (hoto 1) ko zuba kimanin 10 cm3 shirye-shirye dauke da magnesium hydroxide. Sa'an nan kuma ƙara 20-30 cm.3 ruwa (hoto 2) kuma ƙara 'yan digo na nuni (hoto 3). Mix abun ciki na gilashin mai launin shuɗi (hoto 4) sa'an nan kuma zuba ƴan santimita kaɗan3 maganin acid (hoto 5). Cakudar da ke cikin gilashin ya zama rawaya (hoto 6), amma bayan wani lokaci ya sake zama shuɗi (hoto 7). Ƙara wani yanki na maganin acid, mun sake lura da canjin launi (hoto 8 da 9). Za a iya maimaita sake zagayowar sau da yawa.
Wadannan halayen sun faru a cikin beaker:
1. Magnesium oxide yana amsawa da ruwa don samar da hydroxide na wannan ƙarfe:
MgO + N2O → mg(OH)2
Sakamakon fili ba shi da kyau a cikin ruwa (kimanin 0,01 g da 1 dm3), amma yana da tushe mai ƙarfi kuma ƙaddamar da ions hydroxide ya isa ya canza launi.
2. Halin magnesium hydroxide tare da ƙari na hydrochloric acid:
mg (OH)2 + 2HCl → mgCl2 + 2H2O
take kaiwa zuwa neutralization na duk Mg (OH) narkar da cikin ruwa2. Yawan HClaq yana canza yanayi zuwa acidic, wanda zamu iya gani ta hanyar canza launin alamar zuwa rawaya.
3. Wani bangare na magnesium oxide yana amsawa da ruwa (daidaito 1.yana kawar da acid mai yawa (daidaito 2.). Maganin ya sake zama alkaline kuma mai nuna alama ya juya shuɗi. Ana maimaita sake zagayowar.
Canjin ƙwarewa shine canza alamar da aka yi amfani da shi, wanda ke haifar da tasirin launi daban-daban. A cikin ƙoƙari na biyu, maimakon bromthymol blue, za mu yi amfani da phenolphthalein (marasa launi a cikin maganin acid, rasberi a cikin bayani na alkaline). Mun shirya dakatar da magnesium oxide a cikin ruwa (abin da ake kira madarar magnesia), kamar yadda a cikin gwaji na baya. Ƙara 'yan digo na maganin phenolphthalein (hoto 10) da kuma motsa abubuwan da ke cikin gilashin. Bayan an ƙara kaɗan3 hydrochloric acid (hoto 11) cakuda ya zama mara launi (hoto 12). Ta hanyar motsa abubuwan da ke ciki a kowane lokaci, mutum zai iya lura daban-daban: canjin launi zuwa ruwan hoda, kuma bayan ƙara wani yanki na acid, canza launin abin da ke cikin jirgin ruwa (hoto 13, 14, 15).
Abubuwan da suka faru suna ci gaba kamar yadda a cikin ƙoƙari na farko. A gefe guda, yin amfani da alamar alama daban yana haifar da tasirin launi daban-daban. Kusan kowane alamar pH za a iya amfani dashi a cikin gwaji.
Chemical Hourglass Part I:
Chemical Hourglass Part I
Chemical Hourglass Part II:
Chemical Hourglass Part XNUMX
