In the qualitative analysis scheme, magnesium and nickel precipitate from solution upon the addition of sodium hydroxide. Once separated from the remaining cations by filtration or decanting, the solid mixture is acidified and warmed to dissolve magnesium and nickel cations back into solution. Adding ammonia creates a buffer solution. (Remember, HCl and NH₃ makes for NH₄⁺ cation.) The buffered solution should just be basic (say, pH = 8). Adding sodium hydrogen phosphate (Na₂HPO₄) precipitates magnesium as MgNH₄PO₄ (K_sp = 3 x 10^-13).

a. Write the K_sp expression for the dissociation of MgNH₄PO_4.

b. Calculate the molar solubility of the compound in pure water.

c.Calculate the [NH₄⁺] in a pH of 8.

d. Calculate the molar solubility of MgNH₄PO₄ in a solution with pH of 8_.

Draw sodium methoxide and potassium tert-butoxide. How are they different? What products do you expect from reacting each base with 2-bromoheptane? With 1-bromoheptane?

Explain what makes potassium tert-butoxide more sterically hindered than sodium methoxide and why sodium methoxide could also exhibit steric hindrance when it acts as a base.

What are possible side reactions for each of the reactions?

Why do you want to keep everything dry for this reaction?

When the temperature becomes sufficiently high, water vapor starts to decompose into hydrogen gas and oxygen gas according to 2H2O(g) A 2H2(g) + O2(g) Using the following data, and assuming that 6CP is constant for this reaction and has an effective value of Cp = 18.88 J mol–1 K–1 over the temperature range in question,

calculate: (a) the value of the decomposition constant at 1000 K

(b) the percent decomposition of water vapor at 1000 K and one bar total pressure.

H2(g) O2(g) H2O(g)

hf (298.15) (kJ mol–1) 0.00 0.00 –241.82

S298.15 o (J K–1 mol–1) 130.684 205.138 188.825

Find the pH of each of the following mixtures of acids.

7.0×10⁻² molL−1 in HNO3HNO3 and 0.185 molL−1 in HC7H5O2

1.5×10⁻² molL−1 in HBrHBr and 2.0×10⁻² molL−1 in HClO4

9.0×10⁻² molL−1 in HFHF and 0.230 molL−1 in C6H5OH

0.105 molL−1 in formic acid and 4.5×10⁻² molL−1 in hypochlorous acid

1- A 30.00 mL wine sample is titrated with a 1.10×10^-1M solution of sodium hydroxide. The equivalence point is determined to be 34.705 mL. What is the acidity of the wine expressed as (g tartaric acid / L; MW tartaric acid = 150.085 g/mole)?

2- The acidity of a wine sample is 1.15×10¹, expressed as (g citric acid / L wine; MW citric acid = 192.124 g/mole) . The sample is titrated with a 0.100 M solution of sodium hydroxide. The equivalence point is determined to be 23.391 mL. What is the volume of the wine sample analyzed in mL?

What is the theoretical yield in a reaction using 0.50g of N-tert-butoxycarbonyl-L-alanine, 0.63g methyl-L-phenylalaninate hydrochlroide, 0.4mL isobutyl chloroformate, and 0.3mL N-methylmorpholine to yield methyl N-tert-butoxycarbonyl-alanyl-phenylalaninate (Boc-Ala-Phe-OMe)?

The K_f for the formation of Co(NH₃)₆²⁺ is 7.70 × 10⁴.
The K_f for the formation of Co(en)₃²⁺ is 8.70 × 10¹³.

Suppose a 500.0 mL solution contains 1.300 millimoles of Co(NO₃)₂, 100.0 millimoles of NH₃, and 100.0 millimoles of ethylenediamine. What is the concentration of Co²⁺(aq ) in the solution?

(1) Deduce the expressions relating pE to pH, the concentration of sulfate ion, and the partial pressure of hydrogen sulfide gas, given that for the half-reaction, pE° = —3.50 V when the pH is 7.0.

(2) Deduce the partial pressure of hydrogen sulfide when the sulfate ion concentration is 1Q^5 M and the pH is 6.0 for water that is in equilibrium with atmospheric oxygen.

Using the stock solution provided (7% NaCl) and water, prepare the following solutions: i) 1 mL of NaCl solution with an osmolarity of 50 mOsM ii) 1 mL of NaCl solution with an osmolarity of 300 mOsM iii) 1 mL of NaCl solution with an osmolarity of 1200 mOsM

PART A-

Ethylamine, an organic amine, C2H5NH2, a weak base with Kb of 8.3×10−5, reacts with water to form its conjugate acid, C2H5NH+3.

1) Write the equation of dissociation for ethylamine.

Express your answer as a chemical equation. Identify all of the phases in your answer.

2)What is the expression constant dissociation for ethylamine?

PART B - Phosphorous acid dissociates to form dihydrogen phosphite and hydronium ion. Phosphorous acid has Kaof 5.0×10−2.

1)Write the equation dissociation for phosphorous acid.

Express your answer as a chemical equation. Identify all of the phases in your answer.

2)What is the expression constant dissociation for phosphorous acid?

Why naphthalene is less aromatic than benzene?

** Please give a detailed explanation for this answer. thank you!

Enter your answer in the provided box.

Determine the pH of

(a) a 0.15 M NH3 solution.

(b) a solution that is 0.15 M NH3 and 0.40 M NH4Cl.

Kb for NH3 is 1.8 × 10−5

A. What is the hybridization of the central atom in BrF₅?

What are the approximate bond angles in this substance ?
Bond angles =

In the lab, a 2.00 x 10-4 M FeSCN2+ stock solution will be provided. Calculate the volume of stock solution (in mL) required to prepare a 10.00 mL 1.50 x 10-4 M solution. Report your answer to two decimal places. Example: If the calculated volume is 1.2 mL, input 1.20. Exclude units in your answer.

Part A: A calorimeter contains 18.0 mL of water at 13.5∘C. When 2.30 g of X (a substance with a molar mass of 69.0 g/mol) is added, it dissolves via the reaction X(s)+H2O(l)→X(aq) and the temperature of the solution increases to 30.0∘C. Calculate the enthalpy change, ΔH, for this reaction per mole of X. Assume that the specific heat of the resulting solution is equal to that of water [4.18 J/(g⋅∘C)], that density of water is 1.00 g/mL, and that no heat is lost to the calorimeter itself, nor to the surroundings. Part B: the reaction C12H22O11(s)+12O2(g)→12CO2(g)+11H2O(l) in which 10.0 g of sucrose, C12H22O11, was burned in a bomb calorimeter with a heat capacity of 7.50 kJ/∘C. The temperature increase inside the calorimeter was found to be 22.0∘C. Calculate the change in internal energy, ΔE, for this reaction per mole of sucrose.