Saturday
August 2, 2014

Posts by Kaleen


Total # Posts: 15

Chemistry
The following reaction was studied at −10°C. 2 NO(g) + Cl2(g) → 2 NOCl(g) The following results were obtained where the rate of the reaction is given below. [NO]o [Cl2]o INITIAL RATE 0.10 0.10 0.18 0.10 0.20 0.36 0.20 0.20 1.45 What is the rate law? What is the...

Chemistry
What are the units for the rate constant for a second and third -order rate law?

Precalculus
Use one of the identities cos(t + 2πk) = cos t or sin(t + 2πk) = sin t to evaluate each expression. (Enter your answers in exact form.) (a) sin(19π/4) (b) sin(−19π/4) (c) cos(11π) (d) cos(53π/4) (e) tan(−3π/4) (f) cos(π/4) (g...

Chemistry
Calculate to four significant figures, the energy of a photon emitted when an electron falls from n=5 to n=4

Chemistry
Determine the maximum number of electrons that can have each of the following designations: 6f: 4d: 2f: 5d(yz): 3d:

Chemistry
It takes 208.4 kJ of energy to remove one mol of electrons from the atoms on the surface of rubidium metal. If rubidium metal metal is irradiated with 254-nm light, what is the maximum kinetic energy the released electrons can have?

Chemistry
What is the energy of a mole of UV photons having a wavelength of 11 nm?

History
Who was the 19th president?

Chemistry
Calculate [CO32- ] in a 0.019 M solution of CO2 in water (H2CO3). If all the CO32- in this solution comes from the reaction shown below, what percentage of the H+ ions in the solution is a result of the dissociation of HCO3‾? HCO3‾(aq) H+(aq) + CO32-(aq)

Chemistry
Calculate the pH of a 0.053 M (C2H5)2NH solution (Kb = 1.3 10-3).

Chemistry
What mass of KOH is necessary to prepare 799.2 mL of a solution having a pH = 11.65?

Chemistry
Trichloroacetic acid (CCl3CO2H) is a corrosive acid that is used to precipitate proteins. The pH of a 0.050 M solution of trichloroacetic acid is the same as the pH of a 0.040 M HClO4 solution. Calculate Ka for trichloroacetic acid.

Chemistry
A 0.39 M solution of a weak acid is 3.0% dissociated. Calculate Ka.

Chemistry
Monochloroacetic acid, HC2H2ClO2, is a skin irritant that is used in "chemical peels" intended to remove the top layer of dead skin from the face and ultimately improve the complexion. The value of Ka for monochloroacetic acid is 1.35 10-3. Calculate the pH of a 0.22...

Chemistry
A 11.8 mL sample of a HCl solution has a pH of 2.000. What volume of water must be added to change the pH to 4.000?

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