sodium hydroxide dissolves very easily, and exothermically, in water. Using values from the appendix in your text, calculate the Ksp for this salt, as well as the temperature at which this reaction becomes spontaneous. Does the temperature need to be above or below this value in order for the process to proceed without outside intervention? Na0H(s): -379.4 kJ/mol

Apply 1D infinite ?(?) PiB model to the π-network in butadiene (assume that the molecule is linear and use the values 135 and 154 pm for lengths of C=C and C–C bonds).
a) Calculate the wavelength of the radiation that will be absorbed in promoting an electron from HOMO to LUMO in this molecule. Compare this to the experimental value of 217 nm.
b) What does the comparison made suggest to you about estimating the length of the π-network by adding bond lengths for this molecule?

Indicate the concentration of each ion present in the solution formed by mixing the following. (Assume that the volumes are additive.)

(a) 60 mL of 0.100 M HCl and 10.0 mL of 0.480 M HCl

H⁺
M

Cl ^-
M


(b) 15.0 mL of 0.316 M Na₂SO₄ and 10.4 mL of 0.200 M KCl

Na⁺
M

K⁺
M

SO₄^2-
M

Cl ^-
M


(c) 3.50 g of NaCl in 54.4 mL of 0.590 M CaCl₂ solution
Na⁺
M

Ca²⁺
M

Cl ^-
M

Consider the following balanced equation for the combustion of butane, a fuel often used in lighters:

2C4H10(g)+13O2(g)→8CO2(g)+10H2O(g)2C4H10(g)+13O2(g)→8CO2(g)+10H2O(g)

Complete the following table, showing the appropriate masses of reactants and products. If the mass of a reactant is provided, fill in the mass of other reactants required to completely react with the given mass, as well as the mass of each product formed. If the mass of a product is provided, fill in the required masses of each reactant to make that amount of product, as well as the mass of the other product that is formed.

What are the surface functional groups on the stationary phase in normal phase LC and reverse phase LC. Write out the eluotropic series for both normal phase LC and reverse phase LC using the common solvents we discussed in class (acetonitrile, MeOH, diethylether, H₂O, pentane, toluene).  Why acetonitrile is a stronger eluting solvent than toluene in normal phase LC?

The solubilities of the following salts are at a certain temperature. Ag₂SO₄ 0.03m, PbF₂ 1.0x10^-3m, and BaC₂O₄ 10^-4m. Calculate the concentrations of all ions present in each solution. Identify v, v_{_}, and v₊. Find m+/- for each solution.

1. When 15.0 mL of a 9.06×10^-4M sodium phosphate solution is combined with 15.0 mL of a 4.38×10^-4M chromium(III) nitrate solution does a precipitate form?  (yes or no)

For these conditions the Reaction Quotient, Q, is equal to

2. When 18.0 mL of a 5.83×10^-4 M manganese(II) bromide solution is combined with 12.0 mL of a 2.53×10^-4 M ammonium carbonate solution does a precipitate form?  (yes or no)

For these conditions the Reaction Quotient, Q, is equal to .

what are cofactors that are required by enzymes

1. To prepare your ascorbic acid solution, you and your lab partner dissolved 121.34 g of ascorbic acid in a beaker with 50.00 mL of H2O. You and your lab partner then transferred the dissolved ascorbic acid to a 100.0 mL volumetric flask and filled the flask to the mark. What is the concentration of this 100.0 mL solution in mol/L? Then, you and your lab partner then transferred 5.0 mL of the 100.0 mL ascorbic acid solution to a clean 100.0 mL volumetric flask and filled the flask to the mark. What is the new concentration of this 100.0 mL solution in mol/L?

Although argon makes up 0.93 percent of the atmosphere, the gas evaded discovery until 1894, when physicist Lord Rayleigh and chemist William Ramsey identified it. The clues for the discovery of argon came from density measurements of nitrogen.

a) When Rayleigh prepared pure nitrogen from the decomposition of ammonia (NH3), he found that the nitrogen collected had a pressure of 1.0926 atm at 298.15 K. Use this data to calculate the correct density of nitrogen to four significant figures.

A quantity of N2 gas originally held at 3.80 atm pressure in a 1.00 L container at 26.0ºC is transferred to a 10.0 L container at 20.0ºC. A quantity of O2 gas originally at 4.75 atm and 26.0ºC in a 5.00 L container is added to the 10.0 L container already containing the N2.

a) Draw a diagram outlining this experiment, labeling the various quantities.

b) Calculate the total pressure in the new container.

c) What is the mole fraction of the nitrogen gas in the newly formed mixture?

Pertaining to the titration of 25.0mL of 0.100 M HCN (Ka=6.2x10-10) with 0.200 M NaOH, calculate the pH at the following points. a) initial pH, 0.0mL NaOH b) after the addition of 4.0mL NaOH c) after the addition of 6.25 mL NaOH d) at the equivalence point e) after the addition of 17.0 mL NaOH

a clock maker has 15 clock faces. each clock requires 1 face and 2 hands. If the clock maker also has 42 hands, how many clocks can be produced? If the clock maker has only 8 hands, how many clocks can be produced?

Calculate the pH of the final equilibrium mixture in each of the following solutions:

1. 10 mL of 0.005 M HNO₃ are mixed with 5 mL of 0.006 M NaOH [answer: pH=2.87]

2. One mole of HCl is mixed with one mole of ammonia (NH₃; k_b=1.76*10^-5) to form one liter aqueous solution. [answer: pH=4.62]

3. 0.5 moles of HCl is mixed with one mole of ammonia (NH₃; k_b=1.76*10^-5) to form one liter aqueous solution. [answer: pH=9.24]

4. One mole of hydrocyanic acid (HCN; k_a=6.2*10^-10) is mixed with one mole of potassium hydroxide (KOH) to form a one liter aqueous solution. [answer: pH=11.60]

5. One mole of hydrocyanic acid (HCN; k_a=6.2*10^-10) is mixed with 0.5 mole of potassium hydroxide (KOH) to form a one liter aqueous solution. [answer: pH=9.21]

6. 0.35 moles of ammonia (NH₃; k_b=1.76*10^-5), 01. mole ammonium nitrate (N₃H₄O₃), and 0.2 mole nitric acid are mixed to form one liter aqueous solution. [answer: pH=8.93]