Homework Help for Chemistry

Maxima and minima Find the Zeta (zeta) that gives a maximum or minimum for the energy E if Z=2. Z is the nuclear charge, or atomic number; Z=2 for helium. 27.2 eV means 27.2 electron volts. E( Zeta) = (27.2eV)[ Zeta 2 - 2Z Zeta + 5/8 zeta], (5 points) By substituting your answer for Zeta from part b into the equation given for , find the maximum or minimum energy for He with Z=2 (in units of eV). Is the value you found in (b) a maximum or minimum? Explain. (20 points) Find an expression for the location of the maximum or minimum for in the form of rmax/mm = and for the magnitude of the max or min in the form of U(r)max/min =

Calculate the pH of a solution made by mixing 1 L each of 0.30 M acetic acid and 0.10 M sodium hydroxide. [pKa of acetic acid = 4.74] Calculate the pH change that occurs when 30 mL of 0.1 M NaOH are added to 200 mL of the solution in (a). Do you expect the pH change in (b) to be equal to the pH change when 30 mL of 0.1 M NaOH are added to 200 mL of 3.5 times 10-5M HCl? EXPLAIN. Calculate the pH change in (c). Is this what you expected? If not, can you find an explanation (i.e., do you think your prediction in (c) is wrong or do you think you "messed up" in your calculation)? Given that quantitative extraction should be at least 99.9%, answer the following: If the partition coefficient for a metal chelate partitioning between water and chloroform is 6.4, will quantitative extraction be achieved if a 25.0 mL solution of 4.3 times 10-2M ML (metal-ligand complex) is shaken with One 20-mL portion of chloroform Two 10-mL portions of chloroform Can you find the number of extractions needed to achieve quantitative extraction from the general formula? Suppose that a solute has a partition coefficient of 8.8 between water and chloroform. What volume of chloroform will be needed for a single extraction if the fraction of solute remaining in 25.0 mL of water is to be the same as the fraction remaining after three successive extractions with 10.0 mL portions of chloroform? How many grams of CH3COONa should be added to one liter of 0.100 M HC1 to obtain an acid buffer with pH = 4.4. [You are given that pKa of acetic acid is 4.74] Using examples, explain how masking, de-masking, and pH control are used in EDTA titrations Explain how sulfate ion (as an example of an anion) can be analyzed via EDTA titration Ni2+ can be analyzed by back titration using standard Zn2+ at pH 5.5 with xylenol orange indicator. A solution containing 25.00 mL of Ni2+ in dilute HC1 is treated with 25.00 mL of 0.05283 M Na2EDTA. The solution is neutralized with NaOH, and the pH is adjusted to 5.5 with acetate buffer. The solution turns yellow when a few drops of indicator are added. Titration with 0.02299 M Zn2+ requires 17.61 mL to reach the red end point. What is the molarity of Ni2+ in the unknown? In nature, hardwater tends to contain appreciable concentrations of Fe3+ and Cu2+. Explain how EDTA titration is used to determine hardness as Ca2+ and Mg2+ in the presence of these other metal ions.

Calculate the pH of a solution made by mixing 1 L each of 0.30 M acetic acid and 0.10 M sodium hydroxide. [pKa of acetic acid = 4.74] Calculate the pH change that occurs when 30 mL of 0.1 M NaOH are added to 200 mL of the solution in (a). Do you expect the pH change in (b) to be equal to the pH change when 30 mL of 0.1 M NaOH are added to 200 mL of 3.5 times 10-5M HCl? EXPLAIN. Calculate the pH change in (c). Is this what you expected? If not, can you find an explanation (i.e., do you think your prediction in (c) is wrong or do you think you "messed up" in your calculation)? Given that quantitative extraction should be at least 99.9%, answer the following: If the partition coefficient for a metal chelate partitioning between water and chloroform is 6.4, will quantitative extraction be achieved if a 25.0 mL solution of 4.3 times 10-2M ML (metal-ligand complex) is shaken with One 20-mL portion of chloroform Two 10-mL portions of chloroform Can you find the number of extractions needed to achieve quantitative extraction from the general formula? Suppose that a solute has a partition coefficient of 8.8 between water and chloroform. What volume of chloroform will be needed for a single extraction if the fraction of solute remaining in 25.0 mL of water is to be the same as the fraction remaining after three successive extractions with 10.0 mL portions of chloroform? How many grams of CH3COONa should be added to one liter of 0.100 M HC1 to obtain an acid buffer with pH = 4.4. [You are given that pKa of acetic acid is 4.74] Using examples, explain how masking, de-masking, and pH control are used in EDTA titrations Explain how sulfate ion (as an example of an anion) can be analyzed via EDTA titration Ni2+ can be analyzed by back titration using standard Zn2+ at pH 5.5 with xylenol orange indicator. A solution containing 25.00 mL of Ni2+ in dilute HC1 is treated with 25.00 mL of 0.05283 M Na2EDTA. The solution is neutralized with NaOH, and the pH is adjusted to 5.5 with acetate buffer. The solution turns yellow when a few drops of indicator are added. Titration with 0.02299 M Zn2+ requires 17.61 mL to reach the red end point. What is the molarity of Ni2+ in the unknown? In nature, hardwater tends to contain appreciable concentrations of Fe3+ and Cu2+. Explain how EDTA titration is used to determine hardness as Ca2+ and Mg2+ in the presence of these other metal ions.

Calculate the pH of a solution made by mixing 1 L each of 0.30 M acetic acid and 0.10 M sodium hydroxide. [pKa of acetic acid = 4.74] Calculate the pH change that occurs when 30 mL of 0.1 M NaOH are added to 200 mL of the solution in (a). Do you expect the pH change in (b) to be equal to the pH change when 30 mL of 0.1 M NaOH are added to 200 mL of 3.5 times 10-5M HCl? EXPLAIN. Calculate the pH change in (c). Is this what you expected? If not, can you find an explanation (i.e., do you think your prediction in (c) is wrong or do you think you "messed up" in your calculation)? Given that quantitative extraction should be at least 99.9%, answer the following: If the partition coefficient for a metal chelate partitioning between water and chloroform is 6.4, will quantitative extraction be achieved if a 25.0 mL solution of 4.3 times 10-2M ML (metal-ligand complex) is shaken with One 20-mL portion of chloroform Two 10-mL portions of chloroform Can you find the number of extractions needed to achieve quantitative extraction from the general formula? Suppose that a solute has a partition coefficient of 8.8 between water and chloroform. What volume of chloroform will be needed for a single extraction if the fraction of solute remaining in 25.0 mL of water is to be the same as the fraction remaining after three successive extractions with 10.0 mL portions of chloroform? How many grams of CH3COONa should be added to one liter of 0.100 M HC1 to obtain an acid buffer with pH = 4.4. [You are given that pKa of acetic acid is 4.74] Using examples, explain how masking, de-masking, and pH control are used in EDTA titrations Explain how sulfate ion (as an example of an anion) can be analyzed via EDTA titration Ni2+ can be analyzed by back titration using standard Zn2+ at pH 5.5 with xylenol orange indicator. A solution containing 25.00 mL of Ni2+ in dilute HC1 is treated with 25.00 mL of 0.05283 M Na2EDTA. The solution is neutralized with NaOH, and the pH is adjusted to 5.5 with acetate buffer. The solution turns yellow when a few drops of indicator are added. Titration with 0.02299 M Zn2+ requires 17.61 mL to reach the red end point. What is the molarity of Ni2+ in the unknown? In nature, hardwater tends to contain appreciable concentrations of Fe3+ and Cu2+. Explain how EDTA titration is used to determine hardness as Ca2+ and Mg2+ in the presence of these other metal ions.

Calculate the pH of a solution made by mixing 1 L each of 0.30 M acetic acid and 0.10 M sodium hydroxide. [pKa of acetic acid = 4.74] Calculate the pH change that occurs when 30 mL of 0.1 M NaOH are added to 200 mL of the solution in (a). Do you expect the pH change in (b) to be equal to the pH change when 30 mL of 0.1 M NaOH are added to 200 mL of 3.5 times 10-5M HCl? EXPLAIN. Calculate the pH change in (c). Is this what you expected? If not, can you find an explanation (i.e., do you think your prediction in (c) is wrong or do you think you "messed up" in your calculation)? Given that quantitative extraction should be at least 99.9%, answer the following: If the partition coefficient for a metal chelate partitioning between water and chloroform is 6.4, will quantitative extraction be achieved if a 25.0 mL solution of 4.3 times 10-2M ML (metal-ligand complex) is shaken with One 20-mL portion of chloroform Two 10-mL portions of chloroform Can you find the number of extractions needed to achieve quantitative extraction from the general formula? Suppose that a solute has a partition coefficient of 8.8 between water and chloroform. What volume of chloroform will be needed for a single extraction if the fraction of solute remaining in 25.0 mL of water is to be the same as the fraction remaining after three successive extractions with 10.0 mL portions of chloroform? How many grams of CH3COONa should be added to one liter of 0.100 M HC1 to obtain an acid buffer with pH = 4.4. [You are given that pKa of acetic acid is 4.74] Using examples, explain how masking, de-masking, and pH control are used in EDTA titrations Explain how sulfate ion (as an example of an anion) can be analyzed via EDTA titration Ni2+ can be analyzed by back titration using standard Zn2+ at pH 5.5 with xylenol orange indicator. A solution containing 25.00 mL of Ni2+ in dilute HC1 is treated with 25.00 mL of 0.05283 M Na2EDTA. The solution is neutralized with NaOH, and the pH is adjusted to 5.5 with acetate buffer. The solution turns yellow when a few drops of indicator are added. Titration with 0.02299 M Zn2+ requires 17.61 mL to reach the red end point. What is the molarity of Ni2+ in the unknown? In nature, hardwater tends to contain appreciable concentrations of Fe3+ and Cu2+. Explain how EDTA titration is used to determine hardness as Ca2+ and Mg2+ in the presence of these other metal ions.

Calculate the pH of a solution made by mixing 1 L each of 0.30 M acetic acid and 0.10 M sodium hydroxide. [pKa of acetic acid = 4.74] Calculate the pH change that occurs when 30 mL of 0.1 M NaOH are added to 200 mL of the solution in (a). Do you expect the pH change in (b) to be equal to the pH change when 30 mL of 0.1 M NaOH are added to 200 mL of 3.5 times 10-5M HCl? EXPLAIN. Calculate the pH change in (c). Is this what you expected? If not, can you find an explanation (i.e., do you think your prediction in (c) is wrong or do you think you "messed up" in your calculation)? Given that quantitative extraction should be at least 99.9%, answer the following: If the partition coefficient for a metal chelate partitioning between water and chloroform is 6.4, will quantitative extraction be achieved if a 25.0 mL solution of 4.3 times 10-2M ML (metal-ligand complex) is shaken with One 20-mL portion of chloroform Two 10-mL portions of chloroform Can you find the number of extractions needed to achieve quantitative extraction from the general formula? Suppose that a solute has a partition coefficient of 8.8 between water and chloroform. What volume of chloroform will be needed for a single extraction if the fraction of solute remaining in 25.0 mL of water is to be the same as the fraction remaining after three successive extractions with 10.0 mL portions of chloroform? How many grams of CH3COONa should be added to one liter of 0.100 M HC1 to obtain an acid buffer with pH = 4.4. [You are given that pKa of acetic acid is 4.74] Using examples, explain how masking, de-masking, and pH control are used in EDTA titrations Explain how sulfate ion (as an example of an anion) can be analyzed via EDTA titration Ni2+ can be analyzed by back titration using standard Zn2+ at pH 5.5 with xylenol orange indicator. A solution containing 25.00 mL of Ni2+ in dilute HC1 is treated with 25.00 mL of 0.05283 M Na2EDTA. The solution is neutralized with NaOH, and the pH is adjusted to 5.5 with acetate buffer. The solution turns yellow when a few drops of indicator are added. Titration with 0.02299 M Zn2+ requires 17.61 mL to reach the red end point. What is the molarity of Ni2+ in the unknown? In nature, hardwater tends to contain appreciable concentrations of Fe3+ and Cu2+. Explain how EDTA titration is used to determine hardness as Ca2+ and Mg2+ in the presence of these other metal ions.

The formation constant for the reaction Ag +( a q ) + 2NH3( aq ) rightarrow Ag(NH3)2 + ( aq ) is Kf = 1.7 times 107 at 25 degree C. What is Delta G degree at this temperature?

Calculate the pH of a solution made by mixing 1 L each of 0.30 M acetic acid and 0.10 M sodium hydroxide. [pKa of acetic acid = 4.74] Calculate the pH change that occurs when 30 mL of 0.1 M NaOH are added to 200 mL of the solution in (a). Do you expect the pH change in (b) to be equal to the pH change when 30 mL of 0.1 M NaOH are added to 200 mL of 3.5 times 10-5M HCl? EXPLAIN. Calculate the pH change in (c). Is this what you expected? If not, can you find an explanation (i.e., do you think your prediction in (c) is wrong or do you think you "messed up" in your calculation)? Given that quantitative extraction should be at least 99.9%, answer the following: If the partition coefficient for a metal chelate partitioning between water and chloroform is 6.4, will quantitative extraction be achieved if a 25.0 mL solution of 4.3 times 10-2M ML (metal-ligand complex) is shaken with One 20-mL portion of chloroform Two 10-mL portions of chloroform Can you find the number of extractions needed to achieve quantitative extraction from the general formula? Suppose that a solute has a partition coefficient of 8.8 between water and chloroform. What volume of chloroform will be needed for a single extraction if the fraction of solute remaining in 25.0 mL of water is to be the same as the fraction remaining after three successive extractions with 10.0 mL portions of chloroform? How many grams of CH3COONa should be added to one liter of 0.100 M HC1 to obtain an acid buffer with pH = 4.4. [You are given that pKa of acetic acid is 4.74] Using examples, explain how masking, de-masking, and pH control are used in EDTA titrations Explain how sulfate ion (as an example of an anion) can be analyzed via EDTA titration Ni2+ can be analyzed by back titration using standard Zn2+ at pH 5.5 with xylenol orange indicator. A solution containing 25.00 mL of Ni2+ in dilute HC1 is treated with 25.00 mL of 0.05283 M Na2EDTA. The solution is neutralized with NaOH, and the pH is adjusted to 5.5 with acetate buffer. The solution turns yellow when a few drops of indicator are added. Titration with 0.02299 M Zn2+ requires 17.61 mL to reach the red end point. What is the molarity of Ni2+ in the unknown? In nature, hardwater tends to contain appreciable concentrations of Fe3+ and Cu2+. Explain how EDTA titration is used to determine hardness as Ca2+ and Mg2+ in the presence of these other metal ions.

Calculate the pH of a solution made by mixing 1 L each of 0.30 M acetic acid and 0.10 M sodium hydroxide. [pKa of acetic acid = 4.74] Calculate the pH change that occurs when 30 mL of 0.1 M NaOH are added to 200 mL of the solution in (a). Do you expect the pH change in (b) to be equal to the pH change when 30 mL of 0.1 M NaOH are added to 200 mL of 3.5 times 10-5M HCl? EXPLAIN. Calculate the pH change in (c). Is this what you expected? If not, can you find an explanation (i.e., do you think your prediction in (c) is wrong or do you think you "messed up" in your calculation)? Given that quantitative extraction should be at least 99.9%, answer the following: If the partition coefficient for a metal chelate partitioning between water and chloroform is 6.4, will quantitative extraction be achieved if a 25.0 mL solution of 4.3 times 10-2M ML (metal-ligand complex) is shaken with One 20-mL portion of chloroform Two 10-mL portions of chloroform Can you find the number of extractions needed to achieve quantitative extraction from the general formula? Suppose that a solute has a partition coefficient of 8.8 between water and chloroform. What volume of chloroform will be needed for a single extraction if the fraction of solute remaining in 25.0 mL of water is to be the same as the fraction remaining after three successive extractions with 10.0 mL portions of chloroform? How many grams of CH3COONa should be added to one liter of 0.100 M HC1 to obtain an acid buffer with pH = 4.4. [You are given that pKa of acetic acid is 4.74] Using examples, explain how masking, de-masking, and pH control are used in EDTA titrations Explain how sulfate ion (as an example of an anion) can be analyzed via EDTA titration Ni2+ can be analyzed by back titration using standard Zn2+ at pH 5.5 with xylenol orange indicator. A solution containing 25.00 mL of Ni2+ in dilute HC1 is treated with 25.00 mL of 0.05283 M Na2EDTA. The solution is neutralized with NaOH, and the pH is adjusted to 5.5 with acetate buffer. The solution turns yellow when a few drops of indicator are added. Titration with 0.02299 M Zn2+ requires 17.61 mL to reach the red end point. What is the molarity of Ni2+ in the unknown? In nature, hardwater tends to contain appreciable concentrations of Fe3+ and Cu2+. Explain how EDTA titration is used to determine hardness as Ca2+ and Mg2+ in the presence of these other metal ions.

Consider the reaction of iodine with manganese dioxide The equilibrium constant for the overall reaction is 8.30 times 10-7. Calculate E degree cell for the reaction at 25 degree C.

Write a stepwise mechanism for each of the following reactions

Outline a reaction sequence for synthesis of each of the following compounds from the indicated starting material and any other organic or inorganic reagents needed.

What starting materials are needed to synthesize each of the following compounds using an aldol reaction?