Test For Lipids Brown Paper
Biology. Fats: Chemistry and Identification
Introduction : Fats are present in living organisms. These chemical make up sure parts of your trunk. Fats are often stored when present in backlog and too serve as an energy source. Fats are an important part of our diet.
Objective: In this lab, you volition
one. larn that all fat molecules are made up of two kinds of smaller molecules, glycerol and fat acids.
2. employ structural formulas and models of glycerol and fat acids to decide how these molecules join to form fat molecules.
iii. learn how to utilize the solubility examination to tell if a substance is a fat.
iv. learn how to use the brown newspaper test to tell if a substance is a fat.
Materials: scissors - newspaper models - dropper - labels - test tubes - test tube rack - olive, corn or peanut oil - water - brownish paper - unknown substance X, unknown substance Y and unknown substance Z - lighter fluid - test tube stoppers
Office A. Pre-Lab Questions
To better understand the chemistry of fats, it is helpful to report first the small molecules which join to brand up fat. Fatty molecules are made up of ii small "building blocks", or chemical molecules. These molecules are called glycerol and fat acids.
Glycerol . Effigy 1 shows the structural formula of glycerol.
i. What elements are present in glycerol?
2. Are there whatever elements in glycerol that are not in carbohydrates?
3. What is the molecular formula for glycerol?
iv. Are there two times equally many hydrogen atoms as oxygen atoms in glycerol?
Fatty Acids . The second kind of molecule which is part of a fat is a fatty acid. Many different fat acids exit, simply all comprise
hydrocarbon bondage with a carboxyl functional group. Some fatty acids are considered "saturated" where all the carbons are singly bonded and saturated with hydrogen atoms. Other are "unsaturated" where the carbons contain one, two or more double bonds. Hydrogen atoms are removed to form these double bonds. Equally a result, these unsaturated fatty acids contain kinks. These kinks prevent the fatty acids from packing together and therefore they are typically less dumbo. Stearic, oleic and linoleic acids examples of fatty acids. Effigy 2 shows that structural formulas for these three fatty acids.
5. What elements are present in all fatty acids?
vi. a. What is the molecular formula for stearic acid?
b. What is the molecular formula for oleic acid?
c. What is the molecular formula for linoleic acid?
7. How many oxygen atoms are present in each fatty acid?
viii. What functional grouping is present in all fat acids?
Combining Glycerol and Fatty acids to class fats
A fat molecule consists of 1 glycerol molecule and three fatty acrid molecules joined.
� Cutting out the glycerol and fatty acid paper model molecules and effort tot construct a fat molecule.
9. Volition the fat molecule fit together equally pieces in a puzzle?
� Remove 3 -OH ends from the glycerol and three -H ends from the fat acids. Now join the molecules to grade a fat.
10. a. How many glycerol molecules are needed to form a fat molecule?
b. How many fatty acid molecules are needed to course a fat molecule?
� Join the left over -H and -OH ends from your model
eleven. What chemic substances is formed when the -H and -OH ends are joined?
Production of a fat molecule is a chemical reaction . A chemical shorthand way of expressing the formation of a fat is equally follows:
Glycerol + Fatty acid molecules --> Fat + Water molecules
12. How many water molecules are formed when ane fat molecule is produced?
13. A change in the type of fatty acrid molecules results in a different blazon of fat molecule. What molecule remains unchanged in all fats?
Part B. Identification of Fats
Ii dissimilar tests can exist used to determine the presence of a fatty, the solubility exam and the chocolate-brown paper test.
Solubility Test on Known Fats
� Label two test tubes #i and #two
� Add 10 drops of lighter fluid and five drops of oil to tube #1
� Add together 10 drops of cold h2o and five drops of oil to tube #2
� Mix the contents of each tube by gently swirling the tube with contents.
� Look i infinitesimal and then examine the contents of the 2 tubes. Write your observations in the lab report.
A positive solubility test for fats is that the fat dissolves in lighter fluid and not in water. A negative test is that is doesn't dissolve in lighter fluid and may or may not dissolve in water.
Brown Newspaper Test for Fats
� On divide pieces of dark-brown paper, rub one drop of oil and one driblet of water. Oil is a fatty and water is not.
� Allow the paper to dry for a few minutes.
� Examine the pieces of paper to check for a translucent spot. Tape your results in the lab report
A positive dark-brown paper test for fats is the formation of a translucent spot. A negative examination is no translucent spot exists.
Testing Unknown Substances for Fats
Perform the lighter fluid solubility and brown paper test on each of the post-obit substances
(a) substance X
(b) substance Y
(c) substance Z
Tape your observations and bespeak whether the unknown materials contain fats by identifying positive or negative tests for fats.
Biology. Fats: Chemical science and Identification Names:
Office A. Pre-Lab Questions
one. What elements are present in glycerol? ______________________________________________________________
2. Are there any elements in glycerol that are non in carbohydrates? _________________________________________
3. What is the molecular formula for glycerol? __________________________________________________________
four. Are in that location two times as many hydrogen atoms as oxygen atoms in glycerol? _________________________________
5. What elements are present in all fatty acids? __________________________________________________________
six. a. What is the molecular formula for stearic acid?______________________________________________________
b. What is the molecular formula for oleic acid?_______________________________________________________
c. What is the molecular formula for linoleic acid?_____________________________________________________
7. How many oxygen atoms are present in each fatty acid?_________________________________________________
eight. What functional group is nowadays in all fat acids? _____________________________________________________
9. Will the fat molecule fit together as pieces in a puzzle?__________________________________________________
10. a. How many glycerol molecules are needed to course a fat molecule? ______________________________________
b. How many fat acrid molecules are needed to grade a fat molecule?_____________________________________
eleven. What chemical substances is formed when the -H and -OH ends are joined? ________________________________
12. How many h2o molecules are formed when 1 fat molecule is produced? ________________________________
13. A modify in the type of fatty acrid molecules results in a unlike type of fat molecule.
What molecule remains unchanged in all fats?________________________________________________________
Part B. Identification of Fats
| Data Table 1. Results of Tests on Known Fats | ||
| Test | Observation | Effect (+ or - for Fat) |
| Fats with lighter fluid | ||
| Fats with cold h2o | ||
| Fats rubbed on brown newspaper | ||
| Water rubbed on brown paper | ||
| Tabular array 2. Testing Unknown Substances for Fatty. (Identify as + or - for fat exam) | ||||
| Substance | Test | Results | ||
| Solubility Exam | Brown Paper Exam | Presence of Fatty (yes/no) | ||
| Lighter Fluid | Water | |||
| Ten | ||||
| Y | ||||
| Z | ||||
Analysis
one. Proper name the types of molecules and number of each blazon needed to grade a fat molecule. ______________________________
_____________________________________________________________________________________________________
2. List 2 ways that a fatty acid molecule differs from glycerol. _________________________________________________
_____________________________________________________________________________________________________
3. Explain why grease on wear will not come out with cold water. _____________________________________________
____________________________
Test For Lipids Brown Paper,
Source: https://sites.lps.org/sputnam/Biology/U2Biochemistry/lipid_lab.htm
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