230 mL of 0.10 M NaOH are added to 100 mL of 0.10 M H3PO4. What is the pH of the resulting solution?
In: Chemistry
1-Discuss the differences between size exclution chromatography and hydrodynamic chromatography ?
2- When would you use each of these?
In: Chemistry
Q1) why did you have two different indicators in this expriment rather than just phenolphthalein or just methyl orange?
Q2) Was it necessary to use a dry Erlenmeyer flask to prepare the unknown sample for titration or was it okay if the flask was left slightly wet with distilled water after you washed it and before you placed your sample in it? Explain.
Q3) Using your textbook as a resource, suggest two alternative pH indicators that could be used for this experiment instead of phenolphthalein and methyl orange. Explain your choice.
Q4) If the pH indicator used for the titration in step 1 changed color at a lower pH than phenolphthalein what effect would it have on the mass and what percent of the sodium carbonate determined in this experiment? Explain.
In: Chemistry
In Marvin JS Editor how do you make OH into OD?
In: Chemistry
preparation of tetraethylammonium tetrachloromanganate(II) [C2H5)4N]2[MnCl4]
a)AgCl is insoluble in water and nitric acid but it is soluble in ammonia why?
b)the following redox reaction describe the first reaction step of test for Mn.
2Mn2+ + 5S2O8 2– + 8H2O →2MnO4¯+10SO42¯+16H+
what are the roles of each?
a)MnO4-
b)SO4 2-
c)H2O
d)S2O8 2-
e )Mn 2+
In: Chemistry
A 228 mL sample of an aqueous solution contains 2.00 %MgCl2 by mass (molar mass of MgCl2 is 96.9 g/mol). Exactly one-half of the magnesium ions are Mg−28, a beta emitter with a half-life of 21 hours.
What is the decay rate of Mg−28 in the solution after 4.00 days? (Assume a density of 1.02 g/mL for the solution.)
Express your answer using two significant figures(atoms/day)
In: Chemistry
A system containing 2 moles of CO 2 (g) is initially at 25 0 C and 10atm and is confined to a cylinder that has a cross section of 10 cm 2 . The system expands adiabatically against an external pressure of 1 atm until the piston has moved upwards through 20cm. Assume that CO 2 is an ideal gas with C v,m = 28.8 J/K mol. Calculate q, w, Δ U, Δ T and Δ S.
In: Chemistry
in ice-cream making, the ingredients are kept below
0.0°C in an ice-salt bath.
A) assuming that NaCl dissolves completely and forms an ideal
solution, what mass of it is needed to lower the melting point of
5.1 kg of ice to -4.2°C
B)given the same assumptions, what mass of CaCl2 is
needed?
In: Chemistry
A scuba tank has a volume of 2800 cm3. For very deep dives the tank is filled with 50 percent (by volume) pure oxygen and and 50 percent pure helium.
(a) How many molecules are there of each type in the tank if it is filled at 20°C to a gauge pressure of 10 atm?
(b) What is the ratio of the average kinetic energies of the two types of molecule?
(c) What is the ratio of the rms speeds of the two types of molecule?
In: Chemistry
1.Identify the phase transition occurring. The water level in an aquarium tank falls continuously (the tank has no leak).
In: Chemistry
Qualitative Analysis on how to separate these ions using a clear and detailed flow chart: Ag+, Cu+2, Fe+3, Cr+3, Zn+2, Ba+2
The test reagents available are 3M HCl, 6M NH3, 6M NaOH, 3M H2SO4, 3% H2O2, 15M NH3
The confirmatory test reagents available are: 6M acetic acid, 0.2M K4Fe(CN)6, and 0.2M KNCS
In: Chemistry
A solution of benzene (C6H6) and toluene (C7H8) is 25.0 % benzene by mass. The vapor pressures of pure benzene and pure toluene at 25∘C are 94.2 and 28.4 torr, respectively.
1.)Assuming ideal behavior, calculate the vapor pressure of benzene in the mixture.
Express the pressure to three significant figures and include the appropriate units.
2.)Assuming ideal behavior, calculate the vapor pressure of toluene in the mixture.
In: Chemistry
if 5.00ml of 1.25ml chloric acid is titrated with 0.095M sodium hydroxide, what a volume of base will be required to reach the equivalence point?
In: Chemistry
Some Units conversion/ density problems
1. A gold refinery produces a gold ingot weighing 125 pounds. If the gold is drawn into wire whose diameter is 9.25 mm, how many feet of gold wire can be obtained from the ingot? The density of gold is 19.32 grams/cm3 .
2.A 15.0 cm long cylindrical glass tube, sealed at one end, is filled with ethanol. The mass of ethanol needed to fill the tube is found to be 11.86 grams. The density of ethanol is 0.789 grams/mL. Calculate the diameter of the tube in inches.
3. A 40 pound bag of peat moss needs to be spread onto a flower bed that measures 48 inches by 36 inches. Calculate the depth of the peat moss in meters. The density of peat moss is 0.132 grams/cm3 .
Show your work neatly and methodically. Be sure you work supports your answer.
In: Chemistry
Indicate the net charge for the peptide, C-H-A-V-E-C-A-R-R-I-S-T-H-E-G-R-E-A-T-E-S-T, at the given pH values:
(a) pH 1, net charge:
(b) pH 5, net charge:
(c) pH 8, net charge:
(d) pH 14, net charge:
In: Chemistry