Using a 0.20 M phosphate buffer with a pH of 6.0, you add 0.70 mL of 0.52 M HCl to 58 mL of the buffer. What is the new pH of the solution?

Using a 0.30 M phosphate buffer with a pH of 7.1, you add 0.75 mL of 0.48 M NaOH to 45 mL of the buffer. What is the new pH of the solution?

Why are carboxylic acids, ketones and esters suitable compounds for analysis by gas chromatography-mass spectrometry (GCMS)

Hemoglobin and Myoglobin, HOW is oxygen binding regulated? what other mechanisms control oxygen binding in oxygenated vs deoxygenated tissues ( lung v. exercising muscles)?  

The Ksp of Al(OH)3 is 1.0 x 10-33. What is the solubility of Al(OH)3 in 0.0010 M Al(NO3)3? Give your answer using scientific notation and to 2 significant figures (i.e., one decimal place).

Explain what would happen if the hexane was added to the top of the column immediately after adding the sample. This is for isolation of chlorophyll and carotenoid pigments from spinach

Calculate the initcial I^- concentration in a solution containing 3.0 mL of 0.20 M KI, 5.0 mL of 0.15 M (NH4)2S2O8, 5.0 mL of 0.25 M (NH4)SO4, 6.0 mL of 0.10 M KNO3, and 1.0 mL of 0.012 M Na2S2O3.

What is the molarity of a sodium hydroxide solution if 25.0 ml of this solution reacts exactly with 22.30 ml of 0.253 M sulfuric acid?

Thanks!

Consider the insoluble compound copper(II) hydroxide , Cu(OH)2 . The copper(II) ion also forms a complex with ammonia . Write a balanced net ionic equation to show why the solubility of Cu(OH)2 (s) increases in the presence of ammonia and calculate the equilibrium constant for this reaction. For Cu(NH3)42+ , Kf = 6.8×1012 . Use the pull-down boxes to specify states such as (aq) or (s). + + K =

A molecular compound contains 92.3% carbon and 7.7% hydrogen by mass. What is the empirical formula of this compound? If 0.592 mol of the compound weighs 30.78g, what is its molecular formula?

1) A 10.00 ml sample of an aqueous solution of calcium hydroxide is neutralized by 20.00 ml of 0.02000 M NHO₃(aq). What is the molarity of the calcium hydroxide solution? Enter only a numerical value, do not enter units.

2) Suppose you titrate 80.0 mL of 2.00 M NaOH with 20.0 mL of 4.00 M HCl. What is the final concentration of OH^- ions. Enter only a numerical value, do not enter units.

3) Suppose a solution is prepared by dissolving 15.0 g NaOH in 0.150 L of 0.250 M nitric acid. What is the final concentration of OH^- ions in the solution after the reaction has gone to completion. Assume that there is no volume change when adding the grams of NaOH. Enter only a numerical value, do not enter units.

4) A monoprotic acid is an acid that donates a single proton to the solution. Suppose you have 0.140 g of a monoprotic acid dissolved in 35.0 mL of water. This solution is then neutralized with 14.5 mL of 0.110 M NaOH. What is the molar mass of the acid? Express your answer in g/mol. Enter only a numerical value, do not enter units.

5) Which combination of name and formula is NOT correct.

                   a) Barium hydroxide, Ba(OH)₂(aq)

b) Potassium peroxide, K₂O₂(s)

                   c) Phosphoric acid, H₃PO₄(aq)

                   d) Iodic acid, HI(aq)

                   e) Perchloric acid, HClO₄(aq)

2. At 500 °C, cyclopropane (C3H6) rearranges to propene (CH3CH=CH2):   C3H6 (g) ------> CH3CH=CH2 (g)

The reaction is first order and the rate constant is 6.7 x 10-4 s-1. (a) What is the rate law for the reaction, and; (b) if the initial concentration of C3H6 is 0.100 M, what is the concentration of cyclopropane of after 20 min?

3. Butadiene (C4H6) reacts with itself at 250 °C to form a dimer with the formula C8H12.

2 C4H6 (g) ----> C₈H₁₂ (l)

The reaction is second order in C4H6. (a) What is the rate law for the reaction, and; (b) if the rate constant is 4.0 x 10-2 M-1.s-1, and the initial concentration of C₄H₆ is 0.200 M, how long will it take for the concentration of C4H6 to reach 0.04 M?

4.    a) In Q. 2 above what is the half life for the reaction and what is concentration of C₃H₆ after 3 half-lives

   b) In Q. 3 above how long are the first and second half-lives?

I did an organic chemistry lab where I purified a sample of crude biphenyl. The following questions are in regard to the lab.

a. More polar solvents move molecules more rapidly than less polar solvents. If you used a 1:1 hexanes: methanol instead of the 4:1 hexanes:ethyl acetate, would the products elute fater or slower? is the mixture of 1:1 hexanes:methanol a good choice as an eluent with biphenyl?

b. Why do impure compounds have lower melting points than the pure samples? Explan in molecular terms using biphenyl as an example. (we removed methyl orange from biphenyl)

c. Naphthalene has a melting point of 80.3 degrees Celcius. Is that higher or lower than the melting point of biphenyl? Explain the answer in molecular terms (biphenyl has 2 rings connected with a bond and Napthalene is 2 fused rings)

What shape heating and cooling curves suppose to have?

The rate of reduction of [Co(NH3)5(OH2)]3 by Cr(II) is seven orders of magnitude slower than reduction of its conjugate base, [Co(NH3)5(OH)]2, by Cr(II). For the corresponding reductions with [Ru(NH3)6]2, the two differ by less than a factor of 10. What do these observations suggest about their mechanisms?