Physical Chemistry Answers

The time for half change in a first order decomposition of a substance A is 60 seconds. Calculate the rate constant. How much of A will be left after 180 seconds?

The rate of formation of a dimer in a second order reaction is 7.5 × 10−3 mol L−1s−1 at 0.05 mol L−1 monomer concentration. Calculate the rate constant.

The rate law for a reaction of A, B and C has been found to be rate = k [ A]2 [B][L]3/2​  

How would the rate of reaction change when?

(i) Concentration of [L] is quadrupled

(ii) Concentration of both [A] and [B] are doubled

(iii) Concentration of [A] is halved

(iv) Concentration of [A] is reduced to (1/3) and concentration of [L] is quadrupled

PCl₃(g) + Cl₂(g) ⇄ PCl₅(g)          Kc = 6.5

At a certain point in time, a 1.00 L rigid reaction vessel contains 0.5 mol of PCl₃(g), 0.25 mol of Cl₂(g), and 2.5 mol of PCl₅(g). Which of the following describes how the measured pressure in the reaction vessel will change and why it will change that way as the reaction system approaches equilibrium at constant temperature? EXPLAIN

A)The pressure will increase because Q > Kc.

B) The pressure will increase because Q < Kc.

C)The pressure will decrease because Q < Kc.

D)The pressure will decrease because Q > Kc.

(CH3)2O --> CH4 + CO + H2. initial press 300nm Hg after 10secs the press rises by 8.1mm. How long for press to reach 600mm?

Cu(s) + HCI(aq)

given  Ca(OH)₂ + HCl --> CaCl_2 +H₂O

balance the equation

what are the coefficients in front of each molecule

A mixture of noble gases consisting of 5.50g He and 15.0g Ne was placed in a cylinder at 1atm.What is the partial pressure of Helium in the mixture?

.      A 20.00 ml portion of o 0.1000 M butanoic acid (CH₃CH₂CH₂CO₂H), [K_a = 1.54 x 10^-5] was titrated with 0.1000 M NaOH solution.

(a)    Determine the pH of the solution after the addition of 15 ml of NaOH

(b)    What would be a likely pH of the solution at equivalence? Explain your answer.                                                                                         

(c)     Name a suitable indicator for this titration. Justify your answer.

What are transference numbers and how they are related to ionic mobilities