Just answers.

A. A buffer solution that is 0.431 M in HClO and 0.431 M in NaClO has a pH of 7.46.

(1) The addition of 0.01 mol of H₃O⁺ to 1.0 L of this buffer would cause the pH to _________(increase slightly, increase by 2 units,decrease slightly,decrease by 2 units,not change.)

(2) The capacity of this buffer for added OH^- could be increased by the addition of 0.147 mol  _________(of the weak acid,of the salt.)

B. How many grams of solid sodium fluoride should be added to 2.00 L of a 5.23×10^-2M hydrofluoric acid solution to prepare a buffer with a pH of 3.816 ?

grams sodium fluoride =  g.

C.How many grams of solid ammonium bromide should be added to 2.00 L of a 0.287 M ammonia solution to prepare a buffer with a pH of 8.740 ?  

grams ammonium bromide =

chem lab: Solvent Free Wittig Reaction Lab

Wittig reaction= reaction of a phosphonium ylide with an adehyde or ketone to make a new alkene

A.) Another isomer of the product is formed to a small extent. Draw the structure. Why might we expect this product to be formed in only small amounts?

B.) Give a sequence of reactions showing how the ylide used in the lab could be synthesized from triphenylphosphine

A 75.0-mL sample of 0.0500 M HCN (Ka = 6.2e-10) is titrated with 0.212 M NaOH. What is the [H+] on the solution after 3.0 mL of 0.212 M NaOH have been added?

I know the answer is 3.0 x 10^-9 M but I am not sure about the steps please help

what would happen to the values you calculated for kc in the experiment if the beer's law constant (k) value you used was high (e.g.you used 6000 M^-1 when the actual constant had a value of 5000 M^-1) ? Explain your answer.

how do each of the following affect the calculated volume of hydrogen gas at stp?

A: The strip of magnesium used in the experiment was partly oxidized and it was not cleaned before the strip was bent and placed in the buret.

B: The bent strip of magnesium dropped out of the end of the buret and some bubbles of H2 from the reaction were not trapped in the buret.

C: you did not correct the bariometric pressure for the vapor pressure of water.

You are asked to prepare a buffer solution of H₂PO₄^-/HPO₄^2- with a pH of 6.68. A 153.00 mL solution already contains 0.126 M HPO₄^2-.

Hint: you will need to look up the proper K_a in your textbook

How many grams of NaH₂PO₄ must be added to achieve the desired pH? You may assume that the volume change upon salt addition is negligible. in g

1. The degree to which a weak base dissociates is given by the base-ionization constant, Kb. For the generic weak base, B B(aq)+H2O(l)⇌BH+(aq)+OH−(aq) this constant is given by Kb=[BH+][OH−][B] Strong bases will have a higher Kb value. Similarly, strong bases will have a higher percent ionization value. Percent ionization=[OH−] equilibrium[B] initial×100% Strong bases, for which Kb is very large, ionize completely (100%). For weak bases, the percent ionization changes with concentration. The more dilute the solution, the greater the percent ionization. Ammonia, NH3, is a weak base with a Kb value of 1.8×10−5.

partA What is the pH of a 0.245 M ammonia solution?

partB What is the percent ionization of ammonia at this concentration?

2. To understand the relation between the strength of an acid or a base and its pKa and pKb values. The degree to which a weak acid dissociates in solution is given by its acid-ionization constant, Ka. For the generic weak acid, HA, HA(aq)⇌A−(aq)+H+(aq) and the acid-ionization constant is given by Ka=[A−][H+][HA] Similarly, the degree to which a weak base reacts with H2O in solution is given by its base-ionization constant, Kb. For the generic weak base, B, B(aq)+H2O(l)⇌BH+(aq)+OH−(aq) and the base-ionization constant is given by Kb=[BH+][OH−][B]

Another way to express acid strength is by using pKa: pKa=−logKa Another way to express base strength is by using pKb: pKb=−logKb

partA: A new potential heart medicine, code-named X-281, is being tested by a pharmaceutical company, Pharma-pill. As a research technician at Pharma-pill, you are told that X-281 is a monoprotic weak acid, but because of security concerns, the actual chemical formula must remain top secret. The company is interested in the drug's Ka value because only the dissociated form of the chemical is active in preventing cholesterol buildup in arteries. To find the pKa of X-281, you prepare a 0.086 M test solution of X-281 at 25.0 ∘C. The pH of the solution is determined to be 2.40. What is the pKa of X-281? pKa=?

3. Classify each salt as acidic, basic, or neutral. (KBr, NaNO2, AlCl3)

4. Rank the following compounds in order of decreasing acid strength using periodic trends. strongest acid to weakest acid (MgH2, HI, HBr, H2Se)

a. normal boiling point of a solution made from 18.02 g glucose dissolved in 1.250 kg of water b. normal freezing point of a solution made from 180.2 g glucose dissolved in 1250 g of water c. normal freezing point predicted for a solution made from 58.44 g sodium chloride dissolved in 250.0 g of water d. osmotic pressure predicted for a solution made from 5.844 g sodium chloride dissolved in 2000.0 mL of water at 25.0 0 C e. vapor pressure above a solution made from 180.2 g glucose dissolved in 180.2 g of water at 100.0 0 C and normal pressure

A---Write a net ionic equation to show that ethylamine, C₂H₅NH₂, behaves as a Bronsted-Lowry base in water.
-----Write a net ionic equation to show that codeine, C₁₈H₂₁O₃N, behaves as a Bronsted-Lowry base in water.
-----Write a net ionic equation to show that hydrofluoric acid behaves as a Brønsted-Lowry acid in water.

B---Write the K_a expression for an aqueous solution of acetic acid:

----Write the K_a expression for an aqueous solution of hydrofluoric acid:

----Write the K_a expression for an aqueous solution of hypochlorous acid:

C---In the laboratory, a general chemistry student measured the pH of a 0.402 M aqueous solution of formic acid, HCOOH to be 2.054.
Use the information she obtained to determine the K_a for this acid

-----In the laboratory, a general chemistry student measured the pH of a 0.402 M aqueous solution of acetic acid to be 2.587.

Use the information she obtained to determine the K_a for this acid.

----In the laboratory, a general chemistry student measured the pH of a 0.402 M aqueous solution of hydrofluoric acid to be 1.753.
Use the information she obtained to determine the K_a for this acid.

A solution of the sugar mannitol (mol wt 182.2) is prepared by adding 54.66g of mannitol to 1000g of water. The vapor pressure of pure liquid water is 2338 Pa at 20⁰C. Mannitol is nonvolatile and does not ionize in aqueous solutions.

a. Assuming that aqueous mannitol solutions behave ideally, calculate the vapor pressure lowering (the difference between the vapor pressure of pure water and that of the solution) for the above solution at 20⁰C.

b. The observed vapor pressure lowering of the mannitol solution above is 12.40Pa. Calculate the activity coefficient (based on mole fraction) of water in this solution.

c. Calculate the osmotic pressure of the mannitol solution of part (b) when it is measured against pure water and compare it with the osmotic pressure of the ideal solution.

A solution of the sugar mannitol (mol wt 182.2) is prepared by adding 54.66g of mannitol to 1000g of water. The vapor pressure of pure liquid water is 2338 Pa at 20⁰C. Mannitol is nonvolatile and does not ionize in aqueous solutions.

a. Assuming that aqueous mannitol solutions behave ideally, calculate the vapor pressure lowering (the difference between the vapor pressure of pure water and that of the solution) for the above solution at 20⁰C.

b. The observed vapor pressure lowering of the mannitol solution above is 12.40Pa. Calculate the activity coefficient (based on mole fraction) of water in this solution.

c. Calculate the osmotic pressure of the mannitol solution of part (b) when it is measured against pure water and compare it with the osmotic pressure of the ideal solution.

How do heat treatments affect the hardness and impact properties (microstructure)?

Draw the reaction mechanism that shows BH3 adding to the alkene. Why do we get the anti-Markovnikov product?

Which of the following represent a valid set of quantum numbers?
n = 1, l = 0, ml = -1, ms = +1/2
n = 3, l = 2, ml = -2, ms = -1/2
n = 2, l = 2, ml = -1, ms = +1/2
n = 2, l = 1, ml = 0, ms = 0
n = 2, l = 1, ml = 0, ms = -1/2

Show that in a cubic crystal [HKL] direction is always perpendicular to a plane whose Miller indices are (HKL). Show the general proof and not example of specific plane and direction.