CHEM 104 EXPERiMENT 5 BUFFERS
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PORTAGE LEARNiNG EXAM i i i
Name:i
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Date:i
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Experimenti #:i 5i
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Title:i Buffersi
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Purpose:i Thei purposei ofi thisi labi isi toi determinei howi buffersi affecti thei pHi ofi ai solutioni ini orderi
toi observei howi ai bufferi isi resistanti toi pHi changes.i Additionally,i wei determinedi howi enzymesi
activityi isi affectedi byi pH.i
i
Procedure:i
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Parti 1:i Determinei pHi ofi sodiumi acetatei ini wateri &i bufferi
1. 2i pHi electrodesi arei placei ini 2i separatei beakers,i onei filledi withi tapi wateri &i onei isi filledi
withi ai pHi 7i bufferi (bothi havei ani approximatei pHi ofi 7)i
2. Ai scoopi ofi sodiumi acetatei isi addedi toi thei wateri &i toi thei bufferi
3. Thei solutionsi arei swirledi withi ai stirringi sticki toi mixi
4. Wei theni observedi thei pHi changei ofi eachi solutioni
i
Parti 2:i Determinei pHi ofi sodiumi acetatei ini wateri &i bufferi
1. 2i pHi electrodesi arei placei ini 2i separatei beakers,i onei filledi withi tapi wateri &i onei isi filledi
withi ai pHi 7i bufferi
2. 5i dropsi ofi HCli addedi toi thei wateri &i toi thei bufferi
3. Thei solutionsi arei swirledi withi ai stirringi sticki toi mixi
4. Wei theni observedi thei pHi changei ofi eachi solutioni
5. Ani additioni fewi dropsi ofi HCli wasi addedi toi thei wateri &i toi thei bufferi
6. Wei theni observedi thei pHi changei ofi eachi solutioni
i
Parti 3:i Equali concentrationsi ofi basei &i acidi
1. Ai 50i mLi solutioni ofi sodiumi lactatei &i lactici acidi werei placedi ini ai beakeri
2. Ai pHi electrodei wasi placei ini beaker,i whichi wasi 3.85i
3. Concentrationsi werei 0.5i &i 0.5i fori bothi solutionsi (equali concentrations)i
i
Parti 4:i Higheri concentrationi ofi lactatei basei thani acidi
1. Ai solutioni ofi sodiumi lactatei &i lactici acidi werei placedi ini ai beaker,i withi morei basei presenti
2. Wei expecti ai pHi ofi abouti 4.22i
3. Ai pHi electrodei wasi placei ini beaker,i whichi wasi approx.i 4.21i
i
Parti 5:i Higheri concentrationi ofi lactici acidi thani basei
1. Ai solutioni ofi sodiumi lactatei &i lactici acidi werei placedi ini ai beaker,i withi morei acidi presenti
2. Wei wouldi expecti thei pHi toi bei belowi 3.85i
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3. Ai pHi electrodei wasi placei ini beaker,i whichi wasi approx.i 3.41i
, i
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Parti 6:i Testi B-Galactosidasei ini varietyi ofi pHi valuesi
1. 6i tubesi werei obtainedi &i labelledi withi ai specifici pHi (blank,i 6.4,i 6.8,i 7.2,i 7.7,i &i 8.0)i
2. Eachi ofi thei 6i tubesi arei filledi withi thei samei amounti ofi B-Galactosidasei (alli hasi thei
samei concentration)i
3. Thei blanki tubei ai pHi bufferi andi ONPG,i noi enzymei -i thisi isi ai controli
i
4. 0.5i mli ofi ONPGi wasi addedi byi ani automatici pipeti toi eachi tubei &i isi allowedi toi seti
fori ai minutei
i i i i i
i
PORTAGE LEARNiNG EXAM i i i
Name:i
i
Date:i
i
Experimenti #:i 5i
i
Title:i Buffersi
i
Purpose:i Thei purposei ofi thisi labi isi toi determinei howi buffersi affecti thei pHi ofi ai solutioni ini orderi
toi observei howi ai bufferi isi resistanti toi pHi changes.i Additionally,i wei determinedi howi enzymesi
activityi isi affectedi byi pH.i
i
Procedure:i
i
Parti 1:i Determinei pHi ofi sodiumi acetatei ini wateri &i bufferi
1. 2i pHi electrodesi arei placei ini 2i separatei beakers,i onei filledi withi tapi wateri &i onei isi filledi
withi ai pHi 7i bufferi (bothi havei ani approximatei pHi ofi 7)i
2. Ai scoopi ofi sodiumi acetatei isi addedi toi thei wateri &i toi thei bufferi
3. Thei solutionsi arei swirledi withi ai stirringi sticki toi mixi
4. Wei theni observedi thei pHi changei ofi eachi solutioni
i
Parti 2:i Determinei pHi ofi sodiumi acetatei ini wateri &i bufferi
1. 2i pHi electrodesi arei placei ini 2i separatei beakers,i onei filledi withi tapi wateri &i onei isi filledi
withi ai pHi 7i bufferi
2. 5i dropsi ofi HCli addedi toi thei wateri &i toi thei bufferi
3. Thei solutionsi arei swirledi withi ai stirringi sticki toi mixi
4. Wei theni observedi thei pHi changei ofi eachi solutioni
5. Ani additioni fewi dropsi ofi HCli wasi addedi toi thei wateri &i toi thei bufferi
6. Wei theni observedi thei pHi changei ofi eachi solutioni
i
Parti 3:i Equali concentrationsi ofi basei &i acidi
1. Ai 50i mLi solutioni ofi sodiumi lactatei &i lactici acidi werei placedi ini ai beakeri
2. Ai pHi electrodei wasi placei ini beaker,i whichi wasi 3.85i
3. Concentrationsi werei 0.5i &i 0.5i fori bothi solutionsi (equali concentrations)i
i
Parti 4:i Higheri concentrationi ofi lactatei basei thani acidi
1. Ai solutioni ofi sodiumi lactatei &i lactici acidi werei placedi ini ai beaker,i withi morei basei presenti
2. Wei expecti ai pHi ofi abouti 4.22i
3. Ai pHi electrodei wasi placei ini beaker,i whichi wasi approx.i 4.21i
i
Parti 5:i Higheri concentrationi ofi lactici acidi thani basei
1. Ai solutioni ofi sodiumi lactatei &i lactici acidi werei placedi ini ai beaker,i withi morei acidi presenti
2. Wei wouldi expecti thei pHi toi bei belowi 3.85i
i
3. Ai pHi electrodei wasi placei ini beaker,i whichi wasi approx.i 3.41i
, i
i
Parti 6:i Testi B-Galactosidasei ini varietyi ofi pHi valuesi
1. 6i tubesi werei obtainedi &i labelledi withi ai specifici pHi (blank,i 6.4,i 6.8,i 7.2,i 7.7,i &i 8.0)i
2. Eachi ofi thei 6i tubesi arei filledi withi thei samei amounti ofi B-Galactosidasei (alli hasi thei
samei concentration)i
3. Thei blanki tubei ai pHi bufferi andi ONPG,i noi enzymei -i thisi isi ai controli
i
4. 0.5i mli ofi ONPGi wasi addedi byi ani automatici pipeti toi eachi tubei &i isi allowedi toi seti
fori ai minutei
