2) In your own words, explain why it is necessary to select only one wavelength to pass through the sample (i.e. why don’t we just shine white light into the sample and measure the amount of light that passes through?) (5 points)

1. Following reactions are performed in copper experiment. Classify each of these reaction (precipitation, redox, neutralization, dehydration).

1. Cu(s) + 4HNO₃(aq) à Cu(NO₃)₂(aq) + 2NO₂(g) + 2H₂O(l)
2. Cu(NO₃)₂(aq) + 2NaOH(aq) à Cu(OH)₂(s) + 2NaNO₃(aq)
3. Cu(OH)₂(s) à CuO(s) + H₂O(l)
4. CuO(s) + H₂SO₄(aq) à CuSO₄(aq) + H₂O(l)
5. Cu²⁺(aq) + Zn(s) à Cu(s) + Zn²⁺(aq)
6. Zn(s) + 2HCl(aq) à ZnCl₂(aq) + H₂(g)

Calculate the pH of the solution after the addition of the following amounts of 0.0577 M HNO3 to a 80.0 mL solution of 0.0750 M aziridine. The pKa of aziridinium is 8.04

a) 0.00 mL of HNO3 b) 7.72 mL of HNO3 c) Volume of HNO3 equal to half the equivalence point volume d) 99 mL of HNO3

e) Volume of HNO3 equal to the equivalence point f) 107 mL of HNO3

Four ice cubes at exactly 0 ?C with a total mass of 52.5g are combined with 145g of water at 75?C in an insulated container. (?H?fus=6.02 kJ/mol, cwater=4.18J/g??C)

If no heat is lost to the surroundings, what is the final temperature of the mixture?

T=?

Which metal hardening mechanism is reversible by annealing (heat treatment) of the material?

You are given an alpha-titanium alloy to process into a turbine blade. Based on the fact that the alloy has an HCP crystal structure, what general processing technique would you consider for the processing of the turbine blade? Explain your choice.

You have 15.00 mL of a 0.100 M aqueous solution of the weak base C6H5NH2 (Kb = 4.00 x 10-10). This solution will be titrated with 0.100 M HCl.

(a) How many mL of acid must be added to reach the equivalence point?

(b) What is the pH of the solution before any acid is added?

(c) What is the pH of the solution after 5.00 mL of acid has been added?

(d) What is the pH of the solution at the equivalence point of the titration? (e) What is the pH of the solution when 20.00 mL of acid has been added?

Calculate number of CO2 molcules in 2.30*10^-2 mole CO2.

Balance the following redox reaction if it occurs in acidic solution. What are the coefficients in front of Zn and H⁺ in the balanced reaction?

Zn²⁺ (aq) + NH₄⁺ (aq) ? Zn (s) + NO₃

The tetraethyl lead Pb(C2H5)4 in a 25.00 mL sample of aviation gasoline was shaken with 15.00 mL of 0.02263 M I2. (Hint: one mole of I2 reacts with one mole of the tetraethyl lead). After the reaction was complete, the unused I2 was titrated with 8.74 mL of 0.03949 M thiosulfate solution. Calculate the weight of Pb(C2H5)4 (MW = 323.4 g/mol) in each liter of gasoline.

Caluclate the pH of a solution made by mixing 45.0mL of 0.25M HA (K _a= 2.5x10 ^-5) with 15.0mL of 0.75M NaOH

The time to rupture of an S-590 alloy exposed to a tensile stress of 140 MPa at 800C is 9.7 days. Compute the rupture lifetime of this alloy when subjected to a tensile stress of 140 MPa at 650C.

Please, explain in details. Thanks!

A piston-cylinder assembly contains 2.5 kg of saturated refrigerant R-134a with a quality of 10 % at 0 °C (State 1). There is a linear spring mounted on the piston such that when the mixture is heated the pressure reaches 1000 kPa with a volume of 70 L just as the piston touches the stop (State 2). The system is then heated further until a pressure of 1200 kPa is reached (State 3). a) Find the volume of the refrigerant in State 1. b) Calculate the work done by the device during the process from State 1 to State 3. c) Calculate the heat transfer required for this process. Also clearly indicate the direction of the heat transfer (whether into or out of the piston-cylinder system).

If the DCP solution is 0.01278M and you need 23.93 mLs of the DCP solution to completely react with the ascorbic acid, how many grams of ascorbic acid are in your sample? Do not write the answer in scientific notation. Make sure you use the correct number of significant figures and the correct units.