Determination of the Calcium Content of Beer and Water Using Atomic Absorption Spectroscopy

1. Assuming the wort is saturated with Ca3(PO4)2(s), what would happen to the concentration of Ca2+ions in the wort if: (i) More HPO42-ions were added? PO43- Concentration will increase (ii) Ca3(PO4)2 (s) was added? (iii) The pH of the solution was decreased by addition of a suitable acid?

2. Why is LaCl₃ utilized? What changes would be needed in set up of the AAS if LaCl₃ was not used

3. If your two highest concentrations for the calibration both have an absorbance of about 2, what is the problem and how you would correct it?

From the following heats of combustion,

CH₃OH(l) + 3/2O₂(g) → CO₂(g) + 2H₂O(l)        ΔH^o_rxn= –726.4 kJ/mol

C(graphite) + O₂(g) → CO₂(g)                               ΔH^o_rxn = –393.5 kJ/mol

H₂(g) + ½O₂(g) → H₂O(l)                                                  ΔH^o_rxn = –285.8 kJ/mol

Calculate the enthalpy of formation of methanol (CH₃OH) from its elements.

C(graphite) + 2H₂(g) + ½O₂(g) → CH₃OH(l)

A student is running an experiment in which 73.4 grams of BaI2 is needed, but the only jar of reagent in the lab is labelled barium iodide dihydrate. How many grams of the hydrate must the student weigh out in order to get the desired amount of the anhydrous compound?

1. How many GRAMS of potassium are present in 1.73 grams of potassium chromate, K₂CrO₄ ?
grams potassium.

How many GRAMS of potassium chromate can be made from 2.35 grams of potassium ?
grams potassium chromate.

Consider the following reaction: COCl2(g) CO(g) + Cl2(g) If 6.56×10-3 moles of COCl2, 0.377 moles of CO, and 0.372 moles of Cl2 are at equilibrium in a 16.9 L container at 772 K, the value of the equilibrium constant, Kp, is

2.A student ran the following reaction in the laboratory at 597 K:

COCl2(g) CO(g) + Cl2(g)

When she introduced COCl2(g) at a pressure of 0.710 atm into a 1.00 L evacuated container, she found the equilibrium partial pressure of COCl2(g) to be 0.299 atm.  

Calculate the equilibrium constant, Kp, she obtained for this reaction.  

Consider the following reaction where Kp = 1.57 at 600 K: CO(g) + Cl2(g) COCl2(g) If the three gases are mixed in a rigid container at 600 K so that the partial pressure of each gas is initially one atm, what will happen?

Indicate True (T) or False (F) for each of the following:

1. A reaction will occur in which COCl2(g) is produced

2. Kp will decrease.

3. A reaction will occur in which CO is produced.

4. Q is less than K

. 5. The reaction is at equilibrium. No further reaction will occur.

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2.
Consider the following reaction where Kp = 2.74 at 1150 K.  

2SO3(g) 2SO2(g) + O2(g)  

If the three gases are mixed in a rigid container at 1150 K so that the partial pressure of each gas is initially one atm, what will happen?

Indicate True (T) or False (F) for each of the following:

___
T
F
1. A reaction will occur in which SO3(g) is produced.
___
T
F
2. Kp will increase.
___
T
F
3. A reaction will occur in which SO2 is consumed.
___
T
F
4. Qp is greater than Kp.
___
T
F
5. The reaction is at equilibrium. No further reaction will occur.

Using the Cu-Ni phase diagram (Callister, Chap.9, pp. 288) estimate the following quantities for a nominal    composition of 55%Ni – 45% Cu:

a) Liquidus Temperature,

b) Solidus Temperature,

c) The composition of the liqiud and solid phases present in alloy at 1300°C,

d) Using the inverse lever rule, find the amount (by weight) of liquid and

solid phases present in alloy.

1. If you can read at an average rate of 5.15 words per second, how long will it take you to read a 505 page book that has an average of 995 words per page?

2. Let’s say you need to make 12.0 dozen cookies. You decide to make these cookies in batches of 24.0 cookies each. Each batch of cookies requires 27.0 mL of vanilla extract. Each bottle of vanilla extract contains 150. mL of liquid. How many bottles of vanilla extract will you need to make all of your cookies?

3. The label on a bottle of orange juice says that each serving of juice provides you with 480. mg of potassium. The label also says that a serving size is 8.00 fluid ounces and that there are two servings per container. In addition, the label says that 480. mg of potassium is 14.0% of the recommended daily amount of potassium that you ingest in a 2000. calorie diet. How many servings of orange juice do you need to ingest to get 100.% of the recommended daily amount of potassium?

4. My car burns oil at a rate of 1.00 quart every 895 miles. If I travel an average of 83,454 km per year, how many liters of oil do I burn in 11.0 years?

5. If my back yard has an area of 75.5 square zzbts, what is the area in square oobts?

1.00 oobt = 3.43 qvsts

1.00 qvst = 15.4 zzbts

Calculate the thermodynamic favorability of aerobic Mn(II) oxidation and aerobic Fe(II) oxidation at pH 2 and 7. Is it likely that an organism could get “enough” energy to grow from each of these four processes? ​

Consider the titration of 42.8 mLmL of 0.265 MM HFHF with 0.185 MM NaOHNaOH. Calculate the pHpH at each of the following points.

Part A

How many milliliters of base are required to reach the equivalence point?

Express your answer using three significant figures.

Part B

Calculate the pHpH after the addition of 10.7 mLmL of base

Express your answer using two decimal places.

Part C

Calculate the pHpH at halfway to the equivalence point.

Express your answer using two decimal places.

Part D

Calculate the pHpH at the equivalence point.

Express your answer using two decimal places.

Part E

Calculate the pHpH after the addition of 85.6 mLmL of base.

Express your answer using two decimal places.

I would really appreciate it if you could explain this problem step by step, in as much detail as possible, as I am having a difficult time trying to understand it. Thank you :)

How many liters of CO2 can be produced by combustion of 5.80 g butane with 15.0 liters of oxygen . All gases measured at STP.

I appreciate your help!

1. Distinguish between reverse phase and normal phase separations. 2. What is the dynamic range for absorbance spectroscopy? What is the dynamic range for fluorescence spectroscopy? Which has the lowest LOD and why? 3. What types of molecules fluoresce? What is quenching and what makes a good quencher? 4. What is the underlying equation for all partition chromatography methods? Why?

Arrange the 0.15 M solutions of the following compounds in order of increasing acidity (least acidic first).

NH₄I                B. CH₃COONH₄          C. CH₃COOK           D. KCl                 E. CH₃COOH          

         F. KF                   G. HBr                          H. CHCl₂COOH        I. NH₃                  J. CF₃COOH

      ammonia,    K_b = 1.80

What is the key difference in the biosynthesis of purine ribonucleotides vs. the biosynthesis of pyrimidine ribonucleotides?