Chemistry and Biochemical Engineering – BC Set B

Calculate the ∆H for the following reaction using the bond energies given below:

H-H (g)  + I-I (g)  → 2H-I (g)

Bond energies:  H-H = 436 kJ/mol, I-I = 151 kJ/mol, H-I = 297 kJ/mol

The average atomic mass of Ga is 69.72. Naturally occurring Ga is composed of 69Ga, which has an atomic mass of 68.91, and of 71Ga, which has an atomic mass of 70.93. What percentage of naturally occurring Ga is 71Ga?

Sodium Hypobromite

Which of the following carbonates is most soluble in water?

Consider the following reaction. What combination of changed conditions would cause it to proceed more to the right as written?

CS₂(g) + 3O₂(g) → CO₂(g) + 2SO₂(g)            ∆H… = —1110 kJ/mol

Consider the following reaction: H₂(g) + I₂(g) <—> 2 HI(g)

If the value of K_c for this reaction is 25 at 1100 K, and initially only 4.00 M HI(g) is present, what is the equilibrium concentration of I₂(g)?

Bombardment of uranium-235 with a neutron generates tellurium-135, 3 neutrons, and __________.

Carbon-11 is a radioactive isotope of carbon. Its half-life is 20 minutes. What fraction of the initial number of C-11 atoms in a sample will have decayed away after 80 minutes?

Choose the most feasible reaction sequence to synthesize para nitro benzoic acid.

I. Nitration

II. Alkylation

III. Oxidation

Which among the following aromatic compounds is more reactive than benzene towards Aromatic Substitution reactions?

Which among choices A-D, shows the proper arrangement of the given molecules (I-V) in Increasing volatility?

I. ethanoic Acid

II. propanone

III. 1 – propanol

IV. 2 – propanol

V. Formaldehyde

Name the compound: CH2CHC(CH2CH3)2CH3

Triethylamine is a molecule in which the nitrogen atom is __________ hybridized and the CNC bond angle is __________.

Ethanol + ____  →  Ethyl acetate

Identify the major product of this reaction.

Doubling the concentration of HCl

Which of the following salts give acidic aqueous solutions?

(1) KNO3     (2) KCH3COO        (3) NH4NO3          (4) RbI

(5) (NH4)2SO4      (6) BaCl2      (7) NaCN          (8) KNO2

A 500-mg sample containing NaOH (40), Na2CO3 (106), NaHCO3 (84), either alone or in compatible combination is treated with 12.95 mL of 0.100 M HCl to reach the phenolphthalein endpoint and an additional of 18.76 mL to reach the methyl red endpoint.

Identify the compounds (aside from the inerts) present in the sample

I. NaOH

II. Na₂CO₃

III. NaHCO₃

A 500-mg sample containing NaOH (40), Na2CO3 (106), NaHCO3 (84), either alone or in compatible combination is treated with 12.95 mL of 0.100 M HCl to reach the phenolphthalein endpoint and an additional of 18.76 mL to reach the methyl red endpoint.

Calculate the % Sodium Carbonate

A 500-mg sample containing NaOH (40), Na2CO3 (106), NaHCO3 (84), either alone or in compatible combination is treated with 12.95 mL of 0.100 M HCl to reach the phenolphthalein endpoint and an additional of 18.76 mL to reach the methyl red endpoint.

Calculate the percentage of inert in the sample.

An iron ore is analyzed for iron content by dissolving in acid and converting all iron species to Fe²⁺. Fe²⁺ ions are then titrated with standard 0.0150 M K₂Cr₂O₇ solution, converting them to Fe³⁺. 35.6 mL is required to titrate the iron in a 1.68-g ore sample. Calculate % Fe₂O₃ MW: (Fe = 55.85, O = 16)

The pH of a household white vinegar solution is 2.45. This vinegar has a density of 1.09 g/mL. What is the mass percentage of acetic acid in the solution?

A 750.25-mg of alloy nickel was dissolved and treated to remove the impurities. The ammoniacal solution was treated with 50 mL of 0.1075 M KCN and the excess cyanide required 2.25 mL of 0.00925 M AgNO3. Determine %Ni (58.7) in the alloy.

The Tl in a 9.76-g sample of rodenticide was oxidized to the trivalent state and treated with an unmeasured excess Mg/EDTA solution. The reaction is

Tl³⁺ + MgY^{2- →} TlY^– + Mg²⁺

Titration of the liberated Mg 2+ required 13.34 mL of 0.03560 M EDTA. Calculate the percentage of Tl₂SO₄ (504.8 g/mol) in the sample.

Secondary Metabolites are mostly produced during?

DNA contains the following except.

A reversible competitive inhibitor can be mitigated by:

Identify the incorrect molecule – bond pair.

The kinetic properties of the ATPase enzyme, isolated from yeast, which catalyzes the hydrolysis of ATP to form ADP and Pi, are assessed by measuring initial rates in solution, with various ATP concentrations S0 and a total ATPase concentration E0 = 0.60 μM.  From these experiments, it is determined that:        Vmax = 1.20 μM/s; km = 40 μM.

Calculate the values of kcat and the catalytic efficiency (s-1) for ATPase under these conditions.

The kinetic properties of the ATPase enzyme, isolated from yeast, which catalyzes the hydrolysis of ATP to form ADP and Pi, are assessed by measuring initial rates in solution, with various ATP concentrations S0 and a total ATPase concentration E0 = 0.60 μM.  From these experiments, it is determined that:        Vmax = 1.20 μM/s; km = 40 μM.

An inhibitor molecule is added at a concentration of 0.1 mM, and the experiments are repeated.  The apparent Vmax and KM are now found to be 1.2 μM/s, and 80 μM, respectively.  Identify the type of this inhibitor.