A beaker with 135 mLmL of an acetic acid buffer with a pH of 5.000 is sitting on a benchtop. The total molarity of acid and conjugate base in this buffer is 0.100 MM. A student adds 4.70 mLmL of a 0.440 MM HClHCl solution to the beaker. How much will the pH change? The pKapKa of acetic acid is 4.740.

Express your answer numerically to two decimal places. Use a minus ( −− ) sign if the pH has decreased.

When 40.0 mL of 0.580 M H2SO4 is added to 40.0 mL of 1.16 M KOH in a coffee-cup calorimeter at 23.50°C, the temperature rises to 30.17°C. Calculate H of this reaction per mole of H2SO4 and KOH reacted. (Assume that the total volume is the sum of the individual volumes and that the density and specific heat capacity of the solution are the same as for pure water: d = 1.00 g/mL and c = 4.184 J/g×K.) H per mole of H2SO4 reacted:

After you synthesize a molecule, you are asked to determine your product’s melting point and mass, collect its IR spectrum, and analyze it by thin layer chromatography. Which of these experiments gives you information on the purity of the product.

Discuss ethanol as a transportation fuel.

Identify at least three advantages and three disadvantages of its use.

Assess the government’s policy regarding ethanol and make a recommendation as to whether you feel use of ethanol is a feasible approach to decreasing the amount of oil used to power vehicles.

In which of the following pairs of properties are both properties chemical properties? (mark all that are correct)

a) Has a density of 1.45 g/mL and is bright yellow

b) Causes seizures in humans and melts at 1,560 degrees C

c) is flammable and does not react with water

d) Decomposes upon heating and destroys the ozone

e) Has a pungent smell and is a gas at room temperature

f) Melts below room temperature and does not react with sulfur

1 ) What volume of 0.150 M hydrochloric acid reacts with excess lead (II) nitrate solution in order to yield 1.88 g lead ( II) chloride precipitate?

2) Calculate the boiling point and the freezing point of 50.0 g of AlCl3 dissolved in 400g of water, note that AlCl3 produces four particles

3) If 45.5 mL of 0.150 M sodium sulfate solution reacts with 50.0 mL of 0.175 M aqueous barium nitrate, what is the mass of Ba SO4 precipitate

The map of the lac operon is:    POZY  

The promoter (P) region is the start site of transcription through the binding of RNA polymerase before actual mRNA production. Mutationally altered promoters (P^-) cannot bind RNA polymerase. Certain predictions can be made about the effect of P^- mutations. Use your predictions and your knowledge of the lactose system to complete the following table. Insert a “+” where an enzyme is produced and a “-“ where no enzyme is produced. The first one has been done as an example.

1. Determine the concentrations you would use in order to find the rate law for a given reaction.

a.   Here is one set of conditions – fill out the rest of the table with enough sets of conditions to determine the rate law for the reaction:

A + B à C + D

b.   If you determine that the reaction is first order in A and first order in B, fill out the table below with the rate you would expect for each of the conditions you described in part a. (You will have to copy the conditions from part a to the new table.)

c.   What is the rate equation for the reaction?

d.   What is the value of the rate constant?  Be sure to include appropriate units.

e.   If the reaction is zero order in A and 2^nd order in B, fill out the table with the rates you would expect.

f.    What is the rate equation for the reaction?

g.   What is the value of the rate constant?  Be sure to include appropriate units.

2.   How would you determine the initial rates of the reaction experimentally? What measurements would you record and how would you treat the data?

3.   Lets say you have a new reaction and you think that the reaction has a rate equation:  Rate = k[A]²

However, you only have one set of [A] vs time data. Describe how you would determine what the rate equation is from this one set of data.

4.   For a first order reaction, graph the concentration of reactant A ([A]) vs time. On this same graph indicate two half-life time periods. (That is show where the concentration falls by one half, for two time periods).

5.   The carbon-14 decay rate of a sample obtained from a young live tree is 0.260 disintegrations/(s·g). Another sample prepared from an archaeological excavation gives a decay rate of 0.186 disintegrations/(s·g). The half-life of carbon-14 is 5730 years. What is the age of the object?

In the Fluorometric analysis of Quinine in Tonic Water Lab

Pipette 50 μL of the tonic water into the 10 mL flask and dilute to 10.00 mL with 0.05 M H2SO4. This will be your first sample for analysis. Prepare a second sample by diluting the first solution by a factor of 2. You can do this by pipetting 1.00 mL of solution the first solution and 1.00 mL of 0.05 M H2SO4 into a vial.

From the platereader (fluorescence spectrophotometry):

From the calibration curve of standards of 0.15, 0.30, 0.45 ppm (quinine standards (10 ppm) ).

R² = 0.98804

y = 495.11x + 180.33

Calculate the concentration of the quinine in the tonic water as determined by the two sample dilutions. Propagate the error in these results. Determine whether there is a significant difference in the results at 95% confidence.

The percentage composition by mass of a certain fuel is given as C 90%, H 3.5%, O 3% and remainder is incombustible. The fuel is burnt in air and the resulting dry analysis gave the following result by volume: CO2 12.7%, O2 7%, N2 remainder.

a. Find the mass of air supplied per kilogram of fuel

b. If the fuel is completely burned with air (there is no unburned fuel in the exhaust gas), what is the expression that describes this situation?

c. Determine the percentage excess air.

For 540.0mL of a buffer solution that is 0.165M in CH3CH2NH2 and 0.155M in CH3CH2NH3Cl, calculate the initial pH and the final pH after adding 0.020mol of HCl.

For the following reaction,  10.1 grams of  nitrogen gas are allowed to react with  5.97 grams of  oxygen gas .

nitrogen(g) +  oxygen(g)   nitrogen monoxide(g)

What is the maximum mass of  nitrogen monoxide that can be formed?   grams

What mass of the excess reagent remains after the reaction is complete?   grams

For the following reaction,  9.45 grams of  nitrogen monoxide are allowed to react with  8.22 grams of  oxygen gas .

nitrogen monoxide(g) +  oxygen(g)   nitrogen dioxide(g)

What is the maximum mass of  nitrogen dioxide that can be formed?   grams

What mass of the excess reagent remains after the reaction is complete?   grams

25.0mL sample of 0.170 M CH3NH2with 0.145 MM HBr

a) determine pH at equivalence point

b) determine the pHpH after adding 6.0 mLmL of acid beyond the equivalence point.

given:

Initial pH: 11.94

volume of added acid required to reach the equivalence point: 29.3 mL

Name or write the formulas of the following compounds:

Name or write the formulas of the following compounds:

Name or write the formulas of the following compounds:

Name or write the formulas of the following compounds:

Name or write the formulas of the following compounds: