Molecular Mass Of Polymers

The PDI (polydispersity index)

Weight average molecular weight.

Number average molecular weight.

Step 1: Calculate the mass of urea Step 2: Determine the molar mass of urea (CO(NH ) ) Step 3: Calculate the number of moles of urea Step 4: Calculate the volume of solution Step 5: Calculate the molarity Thus, the correct answer is .

Step 1: Review base pairing rules.

In DNA, adenine (A) always pairs with thymine (T), and guanine (G) always pairs with cytosine (C). This is known as complementary base pairing, which is essential for the stability of the DNA double helix.

Step 2: Analyze the provided diagrams.

Option (1) and (3) display incorrect or non-standard base pairing, not consistent with the Watson-Crick model of DNA.

Option (4) represents RNA pairings, which involve uracil instead of thymine.

Conclusion: Only option (2) accurately represents the double-stranded helix structure of DNA with correct base pairings.

Step 1: Understand the properties of Glyptal.

Glyptal is an alkyd resin formed from the esterification of glycerol and phthalic anhydride. It is particularly valued in paints and lacquers for its ability to form a film that dries quickly, provides a robust and durable finish, and adheres well to metal surfaces.

Step 2: Evaluate the other options.

• Melamine, a nitrogen-rich resin, is typically used in laminates and coatings but not primarily in paints.
• Nylon 6 and Nylon 6,6 are polyamides mainly used in fibers and plastics rather than in paint formulations.

Conclusion: Given its specific use in the paint industry for its desirable properties, Glyptal is the correct answer.

Deviation from ideal behavior is maximum when the intermolecular forces become significant. This happens at:

• Low Temperatures: At low temperatures, the kinetic energy of the gas molecules is low, and the intermolecular forces become more dominant.
• High Pressures: At high pressures, the molecules are forced closer together, increasing the effect of intermolecular forces and reducing the free volume available for the molecules.

Comparing the options:

• (1) & 1.0 atm: Relatively moderate conditions.
• (2) & 5.0 atm: Low temperature and high pressure, favoring maximum deviation.
• (3) & 2.0 atm: Low temperature but lower pressure than option (2).
• (4) & 1.0 atm: High temperature and low pressure, favoring ideal behavior.

Therefore, the maximum deviation from ideal behavior occurs at and 5.0 atm.

Final Answer:
& 5.0 atm.

1. Lysine (Lys):

The R group of lysine is -(CH ) -NH .
This makes lysine a basic amino acid due to the presence of an additional amino group in the side chain.

2. Valine (Val):

The R group of valine is -CH(CH ) .
The given option -CH CH(CH ) is incorrect.

3. Threonine (Thr):

The R group of threonine is -CH(OH)CH .
The given option -CH OH is incorrect.

4. Asparagine (Asp):

The R group of asparagine is -CH CONH .
The given option -CH CONH is for asparagine, not aspartic acid. Aspartic acid's R group is -CH COOH.

Therefore, the correct match is Lys - -(CH ) -NH .

Final Answer:
Lys - -(CH ) -NH .

1. Identify the monosaccharide components of sucrose:

Sucrose is a disaccharide made up of glucose and fructose.

2. Identify the structures:

Structure I represents -D-glucose.
Structure II represents -D-fructose.
Structure III represents -D-glucose.
Structure IV represents -D-fructose.

3. Determine the linkage:

In sucrose, -D-glucose and -D-fructose are linked through a glycosidic linkage between C1 of glucose and C2 of fructose.

Therefore, sucrose is a disaccharide of -D-glucose (I) and -D-fructose (II).

Final Answer:
I, II.

1. Teflon:

Teflon (polytetrafluoroethylene or PTFE) is made by the free radical polymerization of tetrafluoroethylene. Persulphate catalysts are used in the polymerization of tetrafluoroethylene to form Teflon. Thus, I is correct.

2. Low density polythene (LDPE):

LDPE is made by the free radical polymerization of ethylene under high pressure and in the presence of peroxide initiators. Triethyl aluminium and titanium tetrachloride (Ziegler-Natta catalyst) are used for the preparation of high-density polyethylene (HDPE), not LDPE. Thus, II is incorrect.

3. Terylene (Dacron):

Terylene is a polyester formed by the condensation polymerization of ethylene glycol and terephthalic acid. Zinc acetate/antimony trioxide is used as a catalyst in the preparation of Terylene. Thus, III is correct.

Therefore, the correctly matched sets are I and III.

Final Answer:
I, III only.

Understanding Vulcanised Rubber: Vulcanisation of rubber is a chemical process where sulfur is added to rubber to improve its properties, such as elasticity, strength, and durability. This is achieved by creating cross-links between polymer chains.
Option (2) correctly represents the structure of vulcanised rubber, where sulfur cross-links the polymer chains. Thus, the correct answer is option (2).