Physical Chemistry Answers

For a solution that is 0.164 M NH₃ and 0.102 M NH₄Cl, calculate the [OH^-].

A voltaic cell is constructed based on the following reaction and initial concentrations:

Fe²⁺(0.0050 M) + Ag⁺(2.0 M) ↔ Fe³⁺(0.0050 M) + Ag(s)

Calculate [Fe²⁺] when the cell reaction reaches equilibrium.

Explain the Heisenberg Uncertainty principle.

i. Micro: Determine the uncertainty in finding the electron in an atom with a 1% uncertainty in determining its speed.

ii. Macro: determine the uncertainty in finding a student along a 100 m track with uncertainty in the determination of his speed.

Write the correct expression for the steady-state form of the Schrödinger wave function?

A hydrocarbon A, contains 87.8%carbon and 12.2%hydrogen by mass. It's relative molecular mass is 82. It decolorizes bromine water and in the presence of nickel to for B. 0.1g of A was found to absorb 27.3cm³ of hydrogen (at STP). B does not decolorize bromine water.

What is the empirical formula of A

The electrodes in the following electrochemical cell are connected to a voltmeter as shown. The half-cell on the right contains a standard silver-silver chloride electrode (a silver wire coated with AgCl(s), as in questions 5 and 6).  

AgCl (s) + e^- → Ag(s) + Cl^- (1 M)      E° = 0.2223 V

The half-cell on the left contains a silver electrode immersed in 100.0 mL of 1.00 x 10^-3 M AgNO₃(aq). A porous plug through which ions can migrate separates the half-cells. 

What is the voltmeter reading after 10.00 mL of 0.0100 M K₂CrO₄ has been added to the half-cell on the left and the mixture has been thoroughly stirred? 

Hint: K_sp of Ag₂CrO₄ = 1.1 x 10^-12

A voltaic cell is constructed based on the following reaction and initial concentrations:

Fe²⁺(0.0050 M) + Ag⁺(2.0 M) ↔ Fe³⁺(0.0050 M) + Ag(s)

Calculate [Fe²⁺] when the cell reaction reaches equilibrium.

The indicator methyl red has a pK_HIn = 4.95. It changes from red to yellow over the pH range from 4.4 to 6.2.

If the indicator is placed in a colourless buffer solution of pH = 4.55, what percent of the indicator will be present in the acid form, HIn?

A common reference electrode consists of a silver wire coated with AgCl(s) and immersed in 1 M KCl (pictured in Question 7).

AgCl (s) + e^- → Ag(s) + Cl^- (1 M)      E° = 0.2223 V

Why would this electrode be easier to use than a standard hydrogen electrode?

A common reference electrode consists of a silver wire coated with AgCl(s) and immersed in 1 M KCl (pictured in Question 7).

AgCl (s) + e^- → Ag(s) + Cl^- (1 M)      E° = 0.2223 V

What is E_cell when this electrode is a cathode in combination with a standard zinc electrode as an anode?