Physical Chemistry Exercises

Question 1: What is a surfactant with an HLB of 5 typically used for?

A. Emulsification for O/W emulsions

C. Surface penetration

B. Increasing the dispersibility of poorly soluble substances

D. Anti-foaming

Question 2: Supercritical fluid is a state of matter:

A. Liquid

C. Both liquid and gas

B. Gas

D. Intermediate between the liquid and gas phases

Question 3: Which of the following substances has the lowest solubility in water?

A. HOCH2CH2OH

B. CHCl3

C. CH3CH2OH

D. CH3(CH2 )8CH2OH

Question 4: What is the most important factor for the kinetic stability of a dispersion?

A. Surface potential

C. Solvation layer

B. Diffusion layer thickness

D. Charge of the adsorption layer

Question 5: Which factors do not increase the solubility of the drug when formulated in solid solutions?

A. Drug has a very small size

B. Drug has increased wettability due to hydrophilic carriers

C. The carrier creates a solvation layer, which helps to dissolve the drug

D. There is no agglomeration or aggregation between particles

Question 6: Average molecular weight by weight is related to which property of polymer solutions?

A. Light scattering

C. Viscosity

B. Saturation concentration

D. Gel formation ability

Question 7: Which adsorption isotherm below characterizes physical adsorption on a non-uniform surface?

A. Curve (I)

B. Curve (II)

C. Curve (III)

D. Curve (IV)

Question 8: Consider a simple second-order reaction of the form 2A → B. Which of the following statements is correct?

A. The half-life of the reaction is independent of the initial concentration of substance A

B. The value of the rate constant is equal to the slope of the line representing the dependence of the reciprocal of the remaining concentration of A on time.

C. The graph representing the concentration of B over time follows the equation [B] [ ] 1( )kt A e o−

= ⋅ −

D. The concentration of substance A decreases linearly over time.

Question 9: How many stages are involved in the complete dissolution process of a polymer?

A. 1

B. 2

C. 3

D. 4

Question 10: Given the phase diagram of two solids as shown in the figure. The mass ratio of solid phase A to the liquid phase AB of the system with a representation point at b is:

A. 0.5

B. 1

C. 0.25

D. 0.65

Question 11: Prepare 100 ml of 3% procaine.HCl injection solution. Adjust the isotonicity with excipient A. Knowing: 1% = 0.120C and ∆���� (��)

1% = 0.2020C. Calculate the mass of the drug and the excipient

∆���� (procaine.HCl

B. mDC = 3g ; mTD = 7.9g

A. mDC = 0.3g ; mTD = 7.9g

C. mDC = 3g; mTD = 0.79g

D. mDC = 0.3g; mTD = 0.79g

Question 12: Which substance is an indifferent electrolyte for the colloidal system ({[m.Fe(OH)3, n. OH-] x. Fe3+} (n-3x). Fe3+)?

A. CaCl2

B. Na2CO3

C. NaOH

D. KOH

Question 13: Steps of the experimental determination of osmotic pressure of drug solution using the boiling point elevation method:

C. Determine the boiling point elevation of the standard solutions → Establish the standard curve п -∆Ts → Determine the boiling point elevation of the test solution → Extrapolate from the graph to obtain the osmotic pressure result.

A. Determine the boiling point of the solvent in the standard solutions → Establish the standard curve п -Ts → Determine the boiling point elevation of the test solution → Extrapolate from the graph to obtain the osmotic pressure result.

B. Determine the boiling point elevation of the standard solutions → Establish the standard curve п -∆Ts → Determine the melting point of the solute in the test solution → Extrapolate from the graph to obtain the osmotic pressure result.

Question 14: Which of the following statements is true about catalysts?

A. For reversible reactions, catalysts change the equilibrium constant of the reaction

B. The catalyst changes the thermodynamic characteristics of the reaction system.

C. The catalyst does not change the thermodynamic characteristics of the reaction system.

D. If a reaction has ΔG > 0 or ΔF > 0, the use of a catalyst can make the reaction proceed faster.

Question 15: Which of the following substances has the highest solubility in 0.1N HCl solution?

D. CH3(CH2)8CH2COOH

A. CH3CH2NH2

C. CH3CH2OH

B. CHCl3

Question 16: Which factor of the adsorption layer has the greatest impact on the stability of the colloidal system?

A. Magnitude of the charge

B. Nature

C. Sign of the charge

D. Thickness

Question 17: Prepare 100 ml of morphine.HCl injection solution 10 mg/ml. Adjust the isotonicity with excipient A. M(morphine.HCl) = 375, Liso(morphine.HCl) =3.3 ; M(A) = 61, Liso(A) =1.8. Calculate the mass of the drug and the excipient

A. mDC = 0.1g ; mTD = 1.4g

C. mDC = 1g; mTD = 1.4g

B. mDC = 1g ; mTD = 0.14g

D. mDC = 0.1g; mTD = 0.14g

Question 18: The rate equation for the reaction A → B is v = k.[A]o.

When the initial concentration of substance A is doubled, the reaction rate will:

C. Double

A. Reduce by half

B. Increase by 4

D. Remain unchanged

Question 19: Colloidal micelles are bounded by …

C. The outer surface of the adsorption layer

A. The surface where the electric charge is completely neutralized

B. The inner surface of the adsorption layer

D. The charged surface of the solid core

Note: The answers in bold are the correct answers for each question.