The Destruction of Jericho The Bible describes the Exodus as a period of 40 years that began with plagues in Egypt and ended with the destruction of Jericho. Archeologists seeking to establish the exact dates of these events have proposed that the plagues coincided with a huge eruption of the volcano Thera in the Aegean Sea Radiocarbon dating of blackened grains from the site of ancient Jericho provides a date of 1315 BC +/- 13 years for the fall of the city. What is the relative amount of ¹⁴C in the old grain vs. the new grain in 2007 AD

(A_t/A_o)_{2007 AD =?}

When light of frequency 4.96×10¹⁵ s^-1 shines on the surface of a metal, electrons are ejected with a maximum kinetic energy of 3.88×10^-19 J.

a) Calculate the wavelength of this light.

b) Find the binding energy of electrons to the metal.

c) What is the longest wavelength of light that will eject electrons from this metal?

7. a). Why should the core of most globular and membrane proteins consist almost entirely of α-helix and β-

sheets?

b). Name the structural and functional advantages of having proteins with a quaternary structure.

c). In a protein, what amino acids (polar or non-polar) would mostly be in the interior folds?

Give a reason for your answer.

d) On the surface of a folded protein, amino acids with what properties would be more predominant?

Give a reason for your answer.

Calculate the frequencies and energies for these 4 wavelengths: 410 nm, 435nm, 487nm, 655nm

A certain mineral used as a food preservative contains 8.242 % potassium, 5.687% aluminum, 5.099% hydrogen, 67.45 % oxygen and 13.52 % sulfur. What is the empirical formula for this compound?

what is the ph of a 0.10m solution of nacn at 25°c (ka=4.9×10^-10 for hcn). I've gotten 5.15 as a pH but the correct answer is 11.15. I don't see how it's 11.15...

Use the table to calculate the total Calories in each food.

Calculate the total Calories in a 10 oz rib eye steak containing 69 g protein, 63 g fat, and 0 g carbohydrate.

a 10 oz rib eye steak:

Cal

Calculate the total Calories in one cup of 1% milk containing 8 g protein, 2.4 g fat, and 12 g carbohydrate.

one cup of 1% milk:

Cal

A water sample is prepared by adding 10-4M NaCl, 10-3 M NaHCO3 and 10-4 M CaCl2 to water. Assume that when these salts dissolve, they dissociate to Na+, Cl- , Ca2+, and HCO3 - and then do not react further. a. Compute the ionic strength of the solution. b. What is the activity of each dissolved ion if the infinitely solution approximation applies and the infinite dilution scale is used? What is the activity of each ion if the extended Debye-Huckel equation applies? c. Calculate the activities of all ions if the NaCl concentration is increased by three order of magnitude to 0.1 M to model an estuarine water.

1. Calculate how to make 500.0 mL of 0.100 M triethanolaime solution.

2. You need to prepare a buffer for biochemistry lab. The required solution is 0.5 M sodium phosphate, pH 7.0. Use the Henderson-Hasselbach equation to calculate the number of moles and grams of monobasic sodium phosphate (NaH₂PO₄) and dibasic sodium phosphate (Na₂HPO₄) necessary to make 1 liter of the solution.

3. Dscribe how you would prepare a 0.1 M glycine buffer of pH 10.0. You have available isoelectric glycine and sodium glycinate. Does it matter if you use sodium glycinate or potassium glycinate for buffer? Why or why not?

4. Describe how you would prepare a 0.20 M Tris-HCl buffer of pH 8.0. The only Tris reagent you have available is Tris base. What other reagent do you need, and how would you use it to prepare the solution?

Please show all work. I appreciate the help!

As the concentration of both hydrochloric acid and acetic acid approach .0001 M, the pH values are converging. Why does this occur?

Mg(s)+2H2O(l)→Mg(OH)2(s)+H2(g).Calculate the number of grams of Mg needed for this reaction to release enough energy to increase the temperature of 75 mL of water from 21 ∘C to 76 ∘C. Calculate the standard enthalpy change for this reaction.

in the synthesis of propyl acetate 4ml of propanol and 4.5 ml of acetyl chloride was used what is the percent yield if a mass product of 3.04 grams ? was obtained

In a reaction bromobenzene is reacting with NO2+ cation to form C6H4NO2Br +C6H3N2O4Br +C6H2N3O6Br Determine the m/z values for bromobenzene and its potential mono-, di-, and tri-nitro derivatives.