1.In comparing the properties of the hand creams you produced, ascertain the function of each of the missing ingredients in the hand cream:
(a)Mineral oil
(b)Triethanolamine
(c)Methyl stearate and propylene glycol
2.The emulsifying agent, a salt, was prepared from two chemicals.
(a)Write the structure of stearic acid.
(b)Write the structure of triethanolamine.
(c)Write the structure of the salt.
(d)In the above salt, label the hydrophobic part of the salt and the hydrophilic part.
3.What evidence do you have from your preparations that suggest that the emulsifying agent is a necessary component of hand creams?
4.Was the pH of all your samples of hand cream the same? Which one is differed? Explain why there was a difference.
5.Two ingredients are necessary in order for a substance to be called a hand cream. What are they and why are they included?
pharm problem 20 marks!!!!
2010-05-04 10:52 pm
回答 (2)
2010-05-09 12:59 am
✔ 最佳答案
1)Your first question is not clear at all , I don't know what you want . Maybe my English is not good enough !! Do you want me to give the main function e.g. mineral oil function in your hand cream . a) Mineral oil ---the oil base which is emulsified in water .
b)triethanolamine---the organic alkaline .
c)methyl stearate & propylene glycol---methylene stearate is an insoluble salt which I will not use as an emulsifier . PG is a solvent & humectant .
2)a)CH3(CH2)16COOH
b) (HOCH2CH2)3N
c)triethanolamine stearate (HOCH2CH2)3N.HOOCC16H35
3) (HOC2H2)3N---hydrophillic(water loving) , the rest part is hydrophobic .
4)You can have same pH by using the same amount TEA .
5)Oil base + emulsifier + water---mixing well----> Hand cream The mineral oil & water .
2010-05-05 9:24 pm
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