(a) How many milliliters of 0.165 M HCl are needed to neutralize completely 25.0 mL of 0.101 M Ba(OH)2 solution? 30.6 Correct: Your answer is correct. ml (b) How many milliliters of 3.50 M H2SO4 are needed to neutralize 25.0 g of NaOH? Incorrect: Your answer is incorrect. mL (c) If 54.8 mL of BaCl2 solution is needed to precipitate all the sulfate in a 544 mg sample of Na2SO4 (forming BaSO4), what is the molarity of the solution? Incorrect: Your answer is incorrect. M (d) If 27.5 mL of 0.125 M HCl solution is needed to neutralize a solution of Ca(OH)2, how many grams of Ca(OH)2 must be in the solution? Incorrect: Your answer is incorrect. g

1-sec-butoxy-3-chloro-1-methylcyclohexane

a) Draw structure

b) Draw all possible stereoisomers with R/S designation and label them A,B, C, etc.

c) List the enantiomers:

d) List the diastereomers:

e) List the meso compounds:

Question 2

Tyrosine is a triprotic amino acid with pKa of 2.17, 9.19, and 10.47 The first proton is removed

from the carboxylic acid ( –COOH), the second from the protonated amine group (–NH3

+) . The

third, with a pKa of 10.47, is the phenolic proton (–OH) on the aromatic ring.

Tyrosine

a) What is the structure of the most protonated form of tyrosine in aqueous solution?

! "#$%!*!'(!)!

b) Write the three acid dissociation equilibria with the correct charge (use Tyr as shorthand

for the part of the molecule excluding the acidic protons, i.e. Tyr(charge), HTyr(charge),

H2Tyr(charge), H3Tyr(charge)).

c) Suppose we titrate a 0.100 M solution of tyrosine hydrochloride salt (often written

Tyr!HCl) with a 0.100 M solution of a strong base (NaOH). Calculate pH at the

following points:

i. initially,

ii. half way to the first,

iii. at the first,

iv. half way to the second,

v. at the second, and

vi. half way to the third equivalence points

d) Using your results calculated in (c) sketch an accurate titration curve.

e) Based on your sketch, identify which equivalence point(s) can be used to identify end

point with an indicator dye.

f) For part (e), indicate what the pKa (or range) of indicator dye should be to minimize

determinate titration error.

g) Write the general expressions for the mass balance and the charge balance for part (c).

. Mg2+ ions are present in seawater, and the metal is often prepared by "harvesting" these ions and converting them to neutral Mg metal. The average magnesium content of the oceans is about 1270 g Mg2+ per ton of seawater, and the density of seawater is about 1.02 g/mL. (Some additional unit conversion factors are given below.) 1 ton = 2000 pounds 1 gallon = 3.7854 L 454 g = 1 pound

(6 pts) (a). How many gallons of seawater would be required to supply 123 kg of magnesium?

(6 pts) (b). Use information from above to find the molarity of Mg2+ ions in seawater?

Determine how many micrograms of phosphorus are in the following solutions:

1. 0.02M KH₂PO₄

2. 0.3M KH₂PO₄

3. 0.5M KH₂PO₄

4. 0.8M  KH2PO4

5. 1M  KH2PO4

6. 1.3M KH₂PO₄

When 2.14 g of a nonelectrolyte solute is dissolved in water to make 165 mL of solution at 22 °C, the solution exerts an osmotic pressure of 821 torr.

Compute the volume of 0.20M silver nitrate needed to precipitate the chloride ion in a 0.60g sample of an unknown that is 45% chloride and the mass of the solid nitrate used to prepare such a solution.

Mercury ions (Hg2+2) can be removed from solution by precipitation with Cl−. Suppose that a solution contains aqueous Hg2(NO3)2.

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

A)Write complete ionic equation to show the reaction of aqueous Hg2(NO3)2 with aqueous sodium chloride to form solid Hg2Cl2 and aqueous sodium nitrate.

B)Write net ionic equation to show the reaction of aqueous Hg2(NO3)2 with aqueous sodium chloride to form solid Hg2Cl2 and aqueous sodium nitrate.

1) Explain with halogens are deactivators, but ortho, para directors, instead of m directors, in an EAS reaction.

2) Draw the energy diagrams for the first step of an electrophilic aromatic substitution reactions of a monosubstituted benzene, when the substituent is an electron-withdrawing group (E), an electron-donating group (D), and a halogen (X), respectively.

You measure the pH of rainwater at 5.4. Calculate the partial pressure of carbon dioxide (assume only CO₂ is present).

PLEASE BE VERY CLEAR WITH WHERE EVERYTHING COMES FROM

Which substances given below produce a basic solution when dissolved in water?

NaCl

KOH

Sucrose

NH3

Vinegar

Suppose an everyday chemical reacts with vinegar. Is the substance more likely to be an acid or a base? Justify your answer.

A 25.0 mL sample of 0.30 M HCOOH is titrated with 0.20 M KOH. What is the pH of the solution after 25.0 mL of KOH has been added to the acid? Ka = 1.8x10^-4

Determine the electron geometry, molecular geometry, and idealized bond angles for each of the following molecules. In which cases do you expect deviations from the idealized bond angle?

CF4

NF3

OF2

H2S

Given that the density of air at 0.987 bar and 27°C is 1.146 kg m⁻³, calculate the mole fraction and partial pressure of nitrogen and oxygen assuming the following conditions.

(a) air consists only of these two gases
mole fraction nitrogen
  
mole fraction oxygen
  
partial pressure nitrogen
  bar
partial pressure oxygen
  bar

(b) air also contains 1.0 mole percent Ar
mole fraction nitrogen
  
mole fraction oxygen
  
partial pressure nitrogen
  bar
partial pressure oxygen
  bar
partial pressure argon
  bar

1.) What is the pH of a solution created by combining 1.34 mole of HOBr and 0.47 mole NaOH in a 1.00L solution? K_{a HOBr} = 2.5 x 10<sup>-9

2.)</sup> What is the pH after 0.24 moles of NaOH is added to a buffer containing 1.00 moles of NH₃ and 1.00 moles NH₄Cl ? K_{b NH3} = 1.8 x 10<sup>-5

3.)</sup> What is the pH of a buffer made by combining 0.69 moles HOBr with 0.65 moles NaOBr in a 100.00mL solution? K_{a HOBr} = 2.5 x 10^-9