Use the following thermodynamic data to calculate ∆S° (universe) for the formation of HBr(g) from its elements at 298K in J/K.   HINT: write the formation reaction for HBr(g)

Species        ∆H_f° (kJ/mol)        S° (J/Kmol)                  Species      ∆H_f° (kJ/mol)      S° (J/Kmol)

HBr(g)           -36.3                   198.59                               Br₂(g)          30.91                245.38

Br₂(l)                  0                   152.23                              H₂(g)              0                     130.6

Arrange the following 0.10 M

solutions in order of increasing acidity: (i) NH4NO3, (ii) NaNO3, (iii) CH3COONH4, (iv) NaF, (v) CH3COONa.

There are several classifications of chemical reactions. Please research a reaction and provide its particular classification and characterization(s).

Balance the following aqueous reactions:

a. CrI₃ + Cl₂ -----> CrO₄^2- + IO₄^1- + Cl^1- (basic solution)

b. Cr(NCS)₆^4- + Ce⁴⁺ ----> Cr³⁺ + Ce³⁺ + NO₃^1- + CO₂ + SO₄^2- (acidic solution)

12. Calculate the pH of a buffer solution made from 0.30 M hydrofluoric acid and 0.70 M sodium fluoride after the addition of 0.08 mol of NaOH to 1.0 L of this solution.  Assume no change in volume.  The Ka for HF is 3.5 • 10-4.

Can someone guide me through this question? The answer is below but I can figure out how they got this answer.

Answer: pH = 4.01

To a 100.0mL volumetric flask are added 1.00 mL volumes of three solutions: 0.0100 M AgNO3, 0.190 M NaBr, and 0.100 M NaCN. The mixture is diluted with deionized water to the mark and shaken vigorously. What mass of AgBr would precipitate from this mixture? (Hint: The Ksp of AgBr is 5.4x10-13 and the Kf of Ag(CN)2- is 1.0x1021)

A 300mL buffer is prepared in which [HCO3-] = 0.2M and [CO3^2-]=0.075M.

a) What is the pH of this buffer (Ka HCO3-=4.7x10^-11)?

b) What is the pH of the buffer if 0.0100 moles of HCl are added?

c) What is the pH of the buffer if 0.0200 moles of NaOH are added?

Balance the following, in basic solution, by the method of half reactions.

C₂H₅OH +MnO₄^- -->C₂H₃O₂^- +MnO_2,

What is the coefficient on water (H₂O) in the product of the balanced equation?

Why can a heavy-water moderated reactor use a lower enrichment uranium fuel than a light water moderated reactor?

Structural data evolves with time, even for simple molecules. Consider the compounds E(CF₃)₃, i.e, the tris(trifluoromethyl) derivatives of P, As, and Sb. C-E-C bond angles were determined by gas-phase electron diffraction in the mid-20^th century and given as: E=P, 99.6°; E=As, 100.1°; E=Sb, 100.0°.          

a) Does this trend seem reasonable, and explain your answer.                    

b) A more rigorous recent similar experiment gave a C-As-C bond angle of 95.4°, compared to a calculated value of 95.9°. In view of this which of the other two C-E-C bond angles seems most suspect, and why?

What is the lead (II) ion concentration in a solution prepared by mixing 341 mL of 0.363 M lead (II) nitrate with 379 mL of 0.359 M sodium fluoride? The Ksp of lead (II) fluoride is 3.6 × 10-8?

Part C - Describe how a white light source could be engineered using CdSe quantum dots.

A 35.0-mL sample of 0.150 M acetic acid (CH3COOH) is titrated with 0.150 MNaOHsolution. Calculate the pH after the following volumes of base have been added.

35.5 mL

Express your answer using two decimal places.