"Low concentrations of dioxin near the detection limit gave the following dimensionless instrument readings: 193.3, 156.5, 150.3, 162.3, 207.3, 148.1, 211.1, 189.7, 122.7, and 193.5. Ten blanks had a mean reading of 47.3. The slope of the calibration curve is 2.55 × 10x9 M–1. Estimate the signal and concentration detection limits and the lower limit of quantitation for dioxin."

I know the signal detection limit is yblank + 3s and the concentration limit is 3s/m, but what is ysample to calculate m?

Using the Line-Angle structure of morphine, circle or highlight all polar regions of the molecule. Make a reasonable prediction about whether your molecule will be soluble in water or not. Explain your reasoning. If the drug seems to be borderline in molecular polarity, making it difficult to predict solubility, explain your reasoning and the difficulty involved. Compare your predictions with the solubility information on the literature.

The following data was generated for an isolated mammalian dihydrofolate reductase.

[7,8-dihydrofolate] (mM)          V (mol/s)                V (mol/s) with methotrexate

                1.1                                  333                                      169

                2.0                                  444                                      265

                5.0                                  667                                      465

A.        Graph the data with and without methotrexate on a Lineweaver-Burk plot. Clearly label which line is which.

B.        Calculate K_m for the enzyme in the presence and absence of methotrexate. Is this a competitive or non-competitive inhibitor?

C.        Considering that deoxynucleotide concentrations are limiting in the cell, what effect will addition of methotrexate have on DNA replication? Explain your reasoning.

1.The reaction of aluminum metal (Al) with oxygen (O2) forms Al2O3. Write a balanced equation for this redox reaction. Write two half reactions to show how many electrons are gained or lost by each species.

Redox Reaction:

Oxidation Reaction:

Reduction Reaction:

2. Be sure to answer all parts. Hydrocarbons are compounds that contain only C and H atoms. When a hydrocarbon reacts with O2, CO2 and H2O are formed. Write a balanced equation for the combustion of the following hydrocarbon, a high-octane components of gasoline. Do not include states of matter in your answer. C8H18 (isooctane)

3.One dose of an antacid contains 750. mg each of Mg(OH)2 and Al(OH)3. How many moles of each compound are contained in a single dose? Use proper scientific notaion to report the answers.

---- × 10 mol Mg(OH)2

----× 10 mol Al(OH)

1. What answer should be reported, with the correct number of significant figures, for the following calculation? (433.621 - 333.9)

1)Suppose the reaction Ca₃(PO₄)₂ + 3H₂SO₄ → 3CaSO₄ + 2H₃PO₄ is carried out starting with 149 g of Ca₃(PO₄)₂

and 91.0 g of H₂SO₄. How much phosphoric acid will be produced?

2)For the reaction N₂(g) + 2H₂(g) → N₂H₄(l), if the percent yield for this reaction is 60.0%, what is the actual mass of hydrazine (N₂H₄) produced when 22.00 g of nitrogen reacts with 5.25 g of hydrogen?

A buffer is prepared by adding 300.0 mL of 0.050 M Ch3COONa to a 500.0 mL of 0.100 M CH3COOH. What is the pH of this buffer? Ka=1.8x10^-5

What is the pH of the buffer upon the addition of 10.0 mL of a 1.2x10^-3 M HCl solution?

For a particular redox reaction MnO2 is oxidized to MnO4– and Cu2 is reduced to Cu . Complete and balance the equation for this reaction in basic solution. Phases are optional.

This is what I keep getting: http://tinypic.com/r/sq1hc3/9

How many microliters of a 872.0 ppm Co2 stock solution are required to prepare 19.00 mL of a 13.0 ng/μL Co2 solution?

W/ Correct Sig Figs

For each of the reactions, calculate the mass (in grams) of the product formed when 3.26g of the underlined reactant completely reacts. Assume that there is more than enough of the other reactant.

Part A Ba(s)?????+Cl2(g)?BaCl2(s) m=_________________g

Part B CaO(s)??????+CO2(g)?CaCO3(s) m=_________________g

Part C 2Mg(s)?????+O2(g)?2MgO(s) m=_________________g

Part D 4Al(s)????+3O2(g)?2Al2O3(s) m=_________________g

Twenty-five milliliters of liquid nitrogen (density = 0.807 g/mL) is poured into a cylindrical container with a radius of 11.3 cm and a length of 17.6 cm . The container initially contains only air at a pressure of 760.0 mmHg (atmospheric pressure) and a temperature of 309 K .

If the liquid nitrogen completely vaporizes, what is the total force (in lb) on the interior of the container at 309 K ?

Part A:

Consider the titration of a 28.7 mL sample of 0.117 M RbOH with 0.186 M HCl.

Calculate the volume of added acid required to reach the equivalence point.
Express your answer to 3 significant figures.

Part B:

Calculate the pH after 8.2 mL of acid have been added.
Express your answer to 2 decimal places.

Part C:

Calculate the pH after 8.2 mL of acid have been added beyond the equivalence point.
Express your answer to 2 decimal places.

Liquid (anhydrous) ammonia, NH3(l), with a boiling point of –33 °C, is often used as an alternate solvent to water. It forms strong hydrogen bonds and the polar molecules can solvate ionic compounds. Anhydrous ammonia also undergoes autoionization. Therefore, there can be acidic, neutral, or basic species in solutions of liquid ammonia.

a) Write the chemical equation, using the Brønsted‐Lowry perspective, that describes the autoionization of NH3(l). (Hints: for water this equation is 2H2O(l) ⇌ H3O+(aq) + OH–(aq); X(am) denotes a solute solvated by ammonia)

b) Identify the species in pure NH3(l) that can act as Brønsted acids and as Brønsted bases. (There are more than one for each case.)

c) Write the equilibrium expression for the autoionization constant Kam of liquid ammonia.

d) At 50°C, the autoionization constant of ammonia Kam is 1030. What are the conditions for “neutral”,

“acidic”, and “basic” liquid ammonia solutions at 50°C?

e) Propose a quantity, analog to the pH, that indicates the acidity of a liquid ammonia solution.

f) For each of these compounds: NH4Cl, LiNH2, KOH, N(CH3)3, when dissolved in liquid ammonia, identify whether it gives rise to an "acidic" solution or a "basic" solution. Write out the chemical equilibrium that shows how it behaves as an acid or a base in NH3(l).

Question 13:

Automobile airbags contain solid sodium azide, NaN3, that reacts to produce nitrogen gas when heated, thus inflating the bag.

2NaN3(s)--->2Na(s)+3N2(g)

Calculate the value of work, w, for the following system if 39.6g of NaN3 reacts completely at 1.00 atm and 22 C.

1. Calculate the number of moles produced

2.Calculate the volume of N2 using the number of moles, pressure, and temperature

3.Calculate the work using the change in volume and the pressure

How many grams of Mg(OH)2 will be needed to neutralize 25mL of stomach acid if stomach acid is .10M HCL?

How many mL of a .10 M NaOH solution are needed to neutralize 15mL of 0.20 M H3PO4 solution?