Colorimetry:
-Definition
-Principle
-Theories
-Instrument used
-Advantages
-Disadvantages

1. What happens when a strong acid suchas HBr dissolves in water?

2. What is the PH of a solution with [H+] of 3.6*10^-4?

3. A sample of urine has a pH 7.9. Is the sample acidic, basic, or neutral? What is the hydrogen ion concentration in the urine sample?

A chemist adds 225.0 mL of a 8.0x10^-5 mmol/L solution of silver (II) oxide solution to a reaction flask. Calculate the mass of micrograms in silver (II) oxide the chemist has added to the flask..Please answer using two significant figures.

The following data show the rate constant of a reaction measured at several different temperatures. Temperature (K) at 310 has a rate constant (1/s) of 4.65×10^−2 . Temperature (K) at 320 has a rate constant (1/s) of 0.139. Temperature (K) at 330 has a rate constant (1/s) of 0.386. Temperature (K) at 340 has a rate constant (1/s) of 1.01. Temperature (K) at 350 has a rate constant (1/s) of 2.52. Part A) Use an Arrhenius plot to determine the activation barrier for the reaction. Part B) Use an Arrhenius plot to determine the frequency factor for the reaction.

If the Xe atom can accomodate a maximum of 14 electrons in its expanded valence shell, what is the formal charge on the Xe atom in the most significant contributor to the resonance hybrid of the molecule XeO4?

Label blood types O and A with the correct monosaccharides. The defining monosaccharide is noted by the gray and orange bond. Each monosaccharide may be used more than once. Note: If any part of this question is answered incorrectly, a single red X will appear on the left-hand side.

Draw a dash-wedge structure for (2S,3R)-3-bromo-6,6-dimethylocta-7-en-2-ol. Draw a dash-wedge structure for (3S,4R)-4-chloro-3,5-dimethylhex-1-yne.

Be sure to answer all parts.

Calculate E o , E, and ΔG for the following cell reactions:

(a) Mg(s) + Sn2+(aq) ⇌ Mg2+(aq) + Sn(s) where [Mg2+] = 0.045 M and [Sn2+] = 0.065 M

E ^o = _________ V

E = ____________ V

ΔG = __________kJ

(b) 3Zn(s) + 2Cr3+(aq) ⇌ 3Zn2+(aq)+ 2Cr(s) where [Cr3+] = 0.080 M and [Zn2+] = 0.0055 M

E ^o = __________ V

E = ____________ V

ΔG = ___________kJ

A student makes a solution containing ammonium chloride and ammonium bromide salts dissolved in concentrated sulfuric acid. She adds a portion of tert-butyl alcohol and shakes the mixture vigorously. After allowing the layers to separate, she dried the alkyl halide layer that resulted and analyzed it by GCMS.

a. Predict the products and their approximate percentages.

b. Draw the complete mechanisms to explain the formation of the products.

c. Explain your percentage predictions

d. Would the change to an aprotic solvent such as DMSO have an effect on the product ratio? How?

1.In gravimetric analysis, it is possible to use the common-ion effect to favor the production of solid precipitate. In this problem you will test this approach to see how effective it is for the gravimetric determination of calcium. Suppose the reaction flask in the gravimetric analysis experiment contains 175 mL of solution before filtering through the Gooch crucible. A precipitate of calcium oxalate monohydrate is collected in the crucible and dried, where:

CaC2O4 * H2O <--> Ca2^+ + C2O4^2- + H2O    Ksp=1.3x10^-8

The measured dry mass of CaC₂O₄·H₂O precipitate is 0.4324 g. In this problem you will determine the mass of Ca²⁺ that remains in the filtrate and is therefore unaccounted for in the precipitate. Specifically, please do the following:

(a) Determine the moles of oxalate ion in the 175-mL reaction flask before precipitation. Use the experimental information in the lab manual. For the purposes of this problem, assume the oxalate ion is totally deprotonated.

(b) Determine the equilibrium molarity of dissolved Ca²⁺ after the precipitation has occurred. [Hint: assume the precipitation first goes to completion; i.e., all the calcium ion from the original sample is in the precipitate. Then set up an ICE table to determine the amount (in moles/L) of the calcium ion that goes back into solution via solubility equilibrium subsequent to the precipitation. Note carefully that that the oxalate (“common ion”) is in excess before the precipitation.]

(c) Determine the mass (in g) of dissolved Ca²⁺ that remains in solution following filtration.

(d) Determine the mass (in g) of calcium ion in the solid precipitate.

(e) From your answers to (c) and (d), determine what percentage of the original calcium mass is lost to the filtrate.

(f) Repeat parts (b) through (e) under conditions in which the oxalate is not in excess; in other words, set the initial oxalate concentration in your ICE table to zero.

1. Write the acid dissociation reaction for following solutions, and calculate the pH for each of them: a) 0.001 M HCl b) 0.005 M H2SO4 c) 0.005 M KOH

Design a separation scheme to separate cations, Al3+, Cu2+, Ni2+, Ag+.

In the Debye-Huckel equation describing the true activity of ions in solution, name and describe 6 terms contained therein that affect the activity, and explain how they do affect it.