Kimyo fanidan laboratoriya mashg’ulotlari

2 - tajriba. Oqsillarning cho’kishi

Reaktiv va materiallar : tuxum oqsili eritmasi, etil spirti, mis (II)- sulfatning to’yingan eritmasi, 20 % li Pb(CH₃COO)₂ eritmasi; probirkalar, menzurka, spirt lampasi yoki isitish asbobi.

1. Oqsillarni qizdirish natijasida cho’kishi (ivishi). Probirkaga tuxum oqsili eritmasidan 2–3 ml quying va qaynaguncha qizdiring. Bunda oqsil pag’a-pag’a bo’lib, loyqa holda cho’kmaga tushishini kuzating.

2. Oqsillarni spirt bilan cho’ktirish. Probirkaga tuxum oqsili eritmasidan 2–3 ml quying va unga ozgina etil spirti qo’shilsa, cho’kma hosil bo’ladi. Agar bu cho’kmaga tezlik bilan dstillangan suv qshilsa cho’kma erib ketadi.

3. Oqsillarning tuzlar ta’sirida cho’kishi. Ikkita probirka olib, ularga tuxum oqsili eritmasidan 1–2 ml quying. So’ngra birinchi probirkaga mis (II)- sulfatning to’yingan eritmasidan, ikkinchisiga esa 20 % li qo’rg’oshin (II)- atsetat eritmasidan qo’shing va probirkalarni chayqating. Bunda har ikala probirkada cho’kma hosil bo’lishini kuzating.

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