If enthalpy change for a reaction is zero, then ΔG∘ equals to (1) – T ΔS∘ (3) – ΔH∘ (2) TΔS∘ (4) In keq Correct Answer: (1) ΔG∘=−TΔS Explanation: The Gibbs free energy change (ΔG∘) is given by the equation: ΔG∘ = ΔH∘ -TΔS∘ where: If enthalpy change is zero (ΔH∘=0), the equation simplifies to: ΔG∘=−TΔS∘ which … Read more
In which one of the following situations, the entropy may be maximum? (1) A class full of students without the teacher being present (2) A class full of students with teacher being present > (3) A class full, of students answering an annual examination monitored by video camera x (4) An empty class room x … Read more
Which of the following statements will always apply when a reversible chemical reaction has attained equilibrium? (1) All reactants will convert to products (2) The reaction proceeds alternately in the forward and reverse directions (3) The Gibbs free energy of the system reaches a minimum, (4) The forward reaction will dominate over the reverse reaction … Read more
The number of water molecules present in a 300 residue soluble protein of spherical shape (diameter = 2nm) having 20% (V/V) water is closest to Assume density of water = 1000kg / (m ^ 2) Avogadro’s number = 6 * 10 ^ 23 (1) 224 (3) 140 (2) 9 (4) 28
Aqueous environment in a spherical endosome a closed vesicle of 100 nm diameter, is at a pH 5.0, in order to denature and hydrolyze the material internalized by a cell. Assuming Avogadro’s number to be 6 * 10 ^ 23 the number of free protons in an endosome is closest to (1) 24 (3) 2400 … Read more
Which of the following salt is the most commonly used reagent for salting out proteins because its high solubility (3.9M in water at 0 deg * C ) permits the achievement of solutions with high ionic strengths (up to 23.4 in water at 0 deg * C ? (1) Ammonium sulfate ( (N*H_{4}) 2 SO … Read more
What will be the ionic strength of 0.1 M (N*H_{4}) 2 SO 4 (1) 0.2 (2) 0.4 (3) 0.6 (4) 0.8
You are provided with 1.0M solutions of NaCl, (NH_{4}) 2 SO 4 , MgSO4 and K_{3}P*O_{4} In which of these solutions would a protein be expected to be lest soluble? (1) NaCl (2) (N*H_{4}) 2 SO 4 (3) MgSO4 (4) K_{3}PO_{4} The solubility of a protein in a salt solution is influenced by the salting-out … Read more
Thallium-208 has a half-life of 3.053 min. How long will a sample containing 120.0 µCi of Thallium-208 take to decay to 7.50 µCi? (1) 6.11 min. (3) 12.21 min. (2) 9.36 min. (4) 18.46 min. Final Answer: The time required for Thallium-208 to decay to 7.50 µCi is 12.21 minutes. Thus, the correct answer is … Read more
In which of the following reactions, is the unit of rat constant and rate of reaction the same? (1) 1″ order reaction (2) 2nd order reaction (3) 3’d order reaction (4) Zero order reaction Answer: The unit of the rate constant and the rate of reaction will be the same for a zero-order reaction. This … Read more