how do you find the wavelength of highest intensity fluorence by looking at the excitation and emission spectrum?
why do some wavelengths show maximum intensity and the rest decrease in fluorescence emission intensity?
In: Chemistry
In: Chemistry
In the structure of testosterone, identify all the primary, secondary, tertiary, and quarternary carbons.
In: Chemistry
A 0.5070 g solid sample containing a mixture of LaCl3 (molar mass = 245.26 g/mol) and Ce(NO3)3 (molar mass = 326.13 g/mol) was dissolved in water. The solution was titrated with KIO3, producing the precipitates La(IO3)3 and Ce(IO3)3. For the complete titration of both La3+ and Ce3+, 42.10 mL of 0.1204 M KIO3 was required. Calculate the mass fraction of La and Ce in the sample.
mass fraction La:
g Lag sample
mass fraction Ce:
g Ceg sample
In: Chemistry
Balance the following redox reaction: NH4+ to NO2- via oxygen reduction
B) Write the full balanced reaction. No fractions.
C) Indicate which species (molecules) are being oxidized and reduced
D) Within these species (molecules), identify which elements are being reduced and oxidized. For these elements, show the change in their oxidation numbers (start and end oxidation numbers).
E) Calculate the pe°cell for this reaction in water and determine whether this reaction will proceed spontaneously (calculate ΔG).
In: Chemistry
In: Chemistry
What volumes of 0.1 M acetic acid, pKa 4.76, and 0.1 M sodium acetate are required to make 1 L of acetate buffer, pH 5.30?
| 776 mL acetate, 224 mL acetic acid | ||
| 351 mL acetate, 649 mL acetic acid | ||
| 540 mL acetate, 460 mL acetic acid | ||
| 712 mL acetate, 288 mL acetic acid |
In: Chemistry
Calculate ΔGo at 25oC for the reaction H2 + I2 D 2HI.
Starting with 1.0 atm H2 and 1.0 atm I2, What is ΔG when: 0.1%, 1%,
10%, 50%, 90%, 99%, and 99.9% has reacted.
In: Chemistry
In: Chemistry
20.00 mL of 0.11 M HNO3 is titrated with 0.25 M NaOH. What
volume of base is required to reach the equivalence point?
Calculate pH at each of the following points in the titration.
a) 4.40 mL
b) 8.80 mL
c) 12.00 mL
In: Chemistry
Calculate the molar solubility at 25C of BaSO4 in seawater in which the concentration of sulfate ion is 2.8g/L. Ksp=BaSO4=9.1X10-11
In: Chemistry
These elementary steps are proposed for a mechanism:
1) 2NO(g) → N2O2(g)
2) 2H2(g) → 4H(g)
3) N2O2(g) + H(g) → N2O(g) + HO(g)
4) 2HO(g) + 2H(g) → 2H2O(g)
5) H(g) + N2O(g) → HO(g) + N2(g)
a) Write the rate law for the first step.
b) Determine the molecularity of the third step.
c) Write the balanced equation for the overall reaction.
In: Chemistry
The following reaction can occur at 298K under
appropriate conditions.
2SO2(g) +O2(g)-----> 2SO3(g)
An equilibrium mixture contain O2(g) and SO3(g) at partial pressure
of 0.50atm and 2.0atm respectively. Using data available in
Appendix 4 of your textbook, determine the equilibrium partial
pressure of SO2 in the mixture. Will this reaction be most favored
at a high or at a low temperature, assuming standard conditions?
Justify your reasoning
Substance.
delta
H°
S°
SO2(g)
-297.
248
SO3(g)
-396.
257
O2(g)
0.
205
In: Chemistry
12. What is the molarity of 0.31 mol of NaCl in enough water to make 2.0 L of solution?
13. What is the molarity of the nitrate ions when 0.60 mol of barium nitrate, Ba(NO3)2, is dissolved in enough water to make 2.0 L of solution?
14. Calculate the molarity of calcium hydroxide that has been prepared by dissolving 2.24 g of calcium hydroxide in water and diluting the solution to a final volume of 4.00 L.
15. Calculate the molarity of the hydroxide ions in a solution that has been prepared by dissolving 70.3 g of barium hydroxide (Ba(OH)2) in water and diluting the solution to a final volume of 4.00 L. (M.W's: Ba 137.3 g/mol., O 16.0 g/mol, and H 1.0 g/mol)
16. How many moles of H+ are in 181 mL of 0.71 M nitric acid, HNO3?
In: Chemistry