Chemistry Answers

 In a redox titration, potassium permanganate, KMnO4, was standardized using a 19.60 g/L FeSO4(NH4)SO4.6H2O, (molar mass = 392.21 g/mol) standard solution. A 20.00 mL of the FeSO4(NH4)SO4.6H2O standard solution, acidified with H2SO4 was put in a conical flask. Potassium permanganate, KMnO4  was placed in the burette and the titration conducted against 20.00 mL of the FeSO4(NH4)SO4.6H2O standard solution in the conical flask.A titre volume 15.50 mL of KMnO4 solution was required to reach the end-point. The titration reaction is:

(i) Balance the above redox reaction in basic medium.

(ii) Calculate the molarity of the 19.60 g/L FeSO4(NH4)SO4.6H2O, standard solution.

(iii) Determine molarity of MnO4-(aq) in the burette.

If a student uses a sodium chloride solution containing 150g/dm³ what mass of sodium chloride is contained in 40cm³ of this solution ?

How many molecules are in 463g of Na20

What is meant by EMF of a cell? How is it measured.

Discuss different techniques for the determination of transition point.

In an aqueous solution at 25°C, if [H₃O⁺] = 2.4 × 10⁻⁴ M, then [OH⁻] is:

Investigate the following:

1. The spontaneity of a process based on entropy.

2. Determine whether entropy increases or decreases if the temperature, the phase, and the number of particles are changed.

3. Explain the second law of thermodynamics and its significance

4. How to use Gibbs free energy to determine the direction of a reaction.

5. State the importance of conversation of energy.

6. Explain the influence of energy change, energy trasformation, and energy utilization to the environment and on Earth as a whole.

1.CO reacts with Cl2 to form phosgene (COCl2), a nerve gas used during World War I. (12 points)

〖Cl〗_(2(g))↔2〖Cl〗_((g)) fast

〖CO〗_((g))+〖Cl〗_((g))→〖COCl〗_((g)) slow

〖COCl〗_((g))+〖Cl〗_((g))→〖COCl〗_(2(g)) fast

(a) Determine the overall reation.

(b) Write the rate law expression for each elementary reaction.

(c) Identify any intermediates.

(d) Determine the overall rate law expression.

2.For each of the following elementary reactions, write the rate equation and molecularity:

2NO+H_2→N_2+H_2 O

P〖Cl〗_3+〖Cl〗_2→〖PCl〗_5

Reaction Mechanism Problem:

The following pair of elementary reactions occur when atomic chlorine in the environment reacts with ozone: (12 points)

Cl+O_(3(g))→〖ClO〗_((g))+O_(2(g)) fast

〖ClO〗_((g) )+O→〖Cl〗_((g))+O_(2(g)) slow

Determine the overall reaction.

Write the rate law expression for each elementary reaction.

Identify any intermediates.

Determine the overall rate law expression.

The following equation describes how nitrogen(II) oxide, NO, reacts with hydrogen, H2: (12 points)

2NO+H_2→N_2+H_2 O_2 slow

H_2 O_2+H_2→2H_2 O fast

Determine the overall reation.

Write the rate law expression for each elementary reaction.

Identify any intermediates.

Determine the overall rate law expression.

what is the volume of a gas at 50.0 degrees Celsius and 0.80 atm, if there are 0.75 moles of the gas present?