Examen
Chromatography Lab – Qs & As (Verified)
- Cours
- Établissement
Chromatography Lab – Qs & As (Verified)
[Montrer plus]
Vendeur
S'abonner
Studyhall
Avis reçus
Aperçu du contenu
Chromatography Lab – Qs & As (Verified)What were food color additives initially used for? ✔️Ans - To make food
more visually appealing to the consumer and mask poor quality.
Why were almost all of the original food color additives phased out? ✔️Ans -
Most were not safe for consumption and were being added to foods with no
health testing.
What could have been done to determine whether a color additive was
harmful before it was used in the food industry? ✔️Ans - They could have
used chromatography to determine the purity of each additive.
Of the original 695 color additives how many are still used today? ✔️Ans - 2
How many color additives total are used today? ✔️Ans - 7
What do all approved food dyes share in common? ✔️Ans - They are
charged, water-soluble organic compounds that bind to natural ionic and
polar sites in large food molecules.
What is the difference between absorption and adsorption ✔️Ans -
Absorption is a physical and chemical event occurring during contact between
materials that have an attraction for each other. Adsorption is different from
absorption in that the molecules of the material physically adhere to the
adsorbent rather than being absorbed into the interspaces of the absorbent
material.
What is chromatography used for? ✔️Ans - To separate organic compounds
for identification or purification.
What are the two main components of chromatography? ✔️Ans - Adsorbent
& eluent
What is another name for the adsorbent? ✔️Ans - Stationary phase
(chromatography paper)
What is another name for the solvent or eluent? ✔️Ans - Mobile phase
, What concept does chromatography work on? ✔️Ans - Compounds to be
separated are slightly soluble in the eluent and will spend some of the time in
the eluent and some of the time in the adsorbent.
What factors determine whether the separation by an eluent will be
successful? ✔️Ans - The affinity of a substance for the eluent versus the
adsorbent allows molecules to be separated by chromatography. (Depends on
polarity)
How can you judge whether a mixture was separated properly by
chromatography? ✔️Ans - If you can clearly see all of the separate colors of
a mixture and they have practically stopped moving as the eluent continues to
make its way up the paper.
Why does changing the polarity of the eluent affect the separation of a mixture
so much? ✔️Ans - Changing the polarity of the eluent will only slightly affect
the solubility of the molecules but may greatly change the relative attraction
for the adsorbent.
What is capillary action? ✔️Ans - The ability of a liquid to flow against
gravity up a narrow tube or porous material.
Where do you put the eluent and carry out the separation? ✔️Ans -
Erlenmeyer flask
What is the most difficult task in chromatography? ✔️Ans - Choosing the
eluent is the most difficult task because the polarity determines the level of
separation that will be achieved; different samples will spend varying amount
of time interacting with the paper and solvent.
What is the rate of flow and what else is it called? ✔️Ans - The rate of flow is
the distance a sample moves along a paper in comparison to the overall
distance the solvent travels; also called the Rf value.
How is the rate of flow calculated? ✔️Ans - Distance sample travels/ overall
distance solvent travels
Les avantages d'acheter des résumés chez Stuvia:
Qualité garantie par les avis des clients
Les clients de Stuvia ont évalués plus de 700 000 résumés. C'est comme ça que vous savez que vous achetez les meilleurs documents.
L’achat facile et rapide
Vous pouvez payer rapidement avec iDeal, carte de crédit ou Stuvia-crédit pour les résumés. Il n'y a pas d'adhésion nécessaire.
Focus sur l’essentiel
Vos camarades écrivent eux-mêmes les notes d’étude, c’est pourquoi les documents sont toujours fiables et à jour. Cela garantit que vous arrivez rapidement au coeur du matériel.
Foire aux questions
Qu'est-ce que j'obtiens en achetant ce document ?
Vous obtenez un PDF, disponible immédiatement après votre achat. Le document acheté est accessible à tout moment, n'importe où et indéfiniment via votre profil.
Garantie de remboursement : comment ça marche ?
Notre garantie de satisfaction garantit que vous trouverez toujours un document d'étude qui vous convient. Vous remplissez un formulaire et notre équipe du service client s'occupe du reste.
Auprès de qui est-ce que j'achète ce résumé ?
Stuvia est une place de marché. Alors, vous n'achetez donc pas ce document chez nous, mais auprès du vendeur Studyhall. Stuvia facilite les paiements au vendeur.
Est-ce que j'aurai un abonnement?
Non, vous n'achetez ce résumé que pour €8,66. Vous n'êtes lié à rien après votre achat.
Peut-on faire confiance à Stuvia ?
4.6 étoiles sur Google & Trustpilot (+1000 avis)
78998 résumés ont été vendus ces 30 derniers jours
Fondée en 2010, la référence pour acheter des résumés depuis déjà 14 ans