Wednesday
November 26, 2014

Posts by Delli


Total # Posts: 27

Physics
Light that is polarized along the vertical direction is incident on a sheet of polarizing material. Only 94% of the intensity of the light passes through the sheet and strikes a second sheet of polarizing material. No light passes through the second sheet. What angle does the ...
February 15, 2009

Physics
a 300kg piano is being lifted at a steady speed from ground level straight up to an apartment 10.0m above ground. The crane that is doing the lifting produces a steady power of 400 W. How much time does it take to lift the piano?
November 25, 2008

Physics Again
In 1954 the English runner Roger Bannister broke the four minute barrier for the mile with a time of 3:59.4s (3 min and 59.4 sec) In 1999 the Morroccan runner Hicham set a record of 3:43.13s for the mile. If these two runners had run in the same race, each running the entire ...
September 14, 2008

Physics
A car makes a trip due north for three fourths of the time and due south one-fourth of the time. The average northward velocity has a magnitude of 27m/s, and the average southward velocity has a magnitude of 17m/s. What is the average velocity, magnitude and direction of the ...
September 14, 2008

Chemistry
What does the ozonolysis followed by hydrolysis of an unsymmetrical, unbranched alkene form?
November 26, 2007

cHEMISTRY
How many electrons are in the p-orbital of the methyl radical (CH3^.)
November 25, 2007

Chemisty Please Help
I still don't understand how to caluculate the number of electrons in the p-orbital. Where do the other two electrons come from to make it three
November 25, 2007

Chem for Dr.Bob
I still don't understand how to caluculate the number of electrons in the p-orbital. Where do the other two electrons come from to make it three
November 25, 2007

Chemistry
How many electrons are there in the p-orbital of a CH3 RADICAL (CH3.) I don't understand how it is 3.
November 25, 2007

CHEMISTRY
How many electrons are there in the p-orbital of a CH3 RADICAL (CH3.) I don't understand how to count 3.
November 25, 2007

CHEMISTRY
How many electrons are there in the p-orbital of a CH3 RADICAL (CH3.) I don't understand how it is 3.
November 25, 2007

CHEMISTRY
How many electrons does the p-orbital of a methyl radical carbon CH3^. contain?
November 25, 2007

Chemistry
A 0.00400- mole sample of 2-chloro-2methylpropane is added to 150Ml of water, and the mixture is stirred till the p H levels off. What is the p H of the solution?
November 12, 2007

CHEMISTRY
C12H20(Y)--> 22CH2=O+ 2CH3C(=O)CH2C(=O)CH3 The reagents used are ozone, Zn and H20 Give condensed formula of C12H20Y
November 12, 2007

CHEMISTRY
The pKa values of acetylene, ehtylene and ethane are 25, 44 and 50 respectively. This means that acetylene is the strongest acid of the three.Explain the order of acidity for the above hydrocarbons
November 4, 2007

CHEMISTRY
Is it possible to obtain pure (200-proof) ethanol using fractional distillation from a fermentation mixture that contains equal amounts of water and ethanol? Explain your answer. I know that some water will still remain i would just like to know why some water vapor will be ...
September 21, 2007

CHEMISTRY
Is it possible to obtain pure (200-proof) ethanol using fractional distillation from a fermentation mixture that contains equal amounts of water and ethanol? Explain your answer.
September 20, 2007

CHEMISTRY
How many moles of Calcium chloride can be added to 1.5L of 0.020potassium sulphate before a precipitate is expected? Assume that the volume is not chnaged significantly. CaSO4 ==> Ca^+2 + SO4^= Ksp = (Ca^+)(SO4^=) = ??. Look it up. (SO4^=) = 0.02 M Use Ksp to calculate (Ca...
May 14, 2007

CHEMISTRY
Calculate Kp at 500 deg C for the reaction- 4No2+6H2O <---> 4NH3+5O2. The value for Kc at 500 deg C is equal to 0.456. Kc = KpRT-delta n where delta n = ngas products - ngas reactants
May 12, 2007

FOR DR. BOB
With regards to my last question about the acid. Just to clarify, the [HA] that I should use is 0.12 which is the concentration of acid-concentration os base? right. (HA) = 0.12 [that's 0.20 - 0.08 = 0.12). And the base, which is (A^-), is 0.08, or course.
May 11, 2007

CHEMISTRY FOR DR. BOB or anyone else
A hypothetical weak acid HA, was combined with NaOH in the following proportions: 0.20 mol HA, 0.08 mol NaOH. The mixture was then diluted to a total volume of 1L, and the pH measured. (a) If pH=4.80, what is the pKa of the acid (b) how many additional moles of NaOH should be ...
May 11, 2007

CHEMISTRY FOR DR. BOB or anyone else
A hypothetical weak acid HA, was combined with NaOH in the following proportions: 0.20 mol HA, 0.08 mol NaOH. The mixture was then diluted to a total volume of 1L, and the pH measured. (a) If pH=4.80, what is the pKa of the acid (b) how many additional moles of NaOH should be ...
May 11, 2007

CHEMISTRY HELP DR.BOB
WHAT IS PK2? pK2 for H3PO4. Look in your text for k2 for H3PO4. My text, but it's an OLD OLD one lists k2 of 6.2E-8 and pK2 = 7.21. DRBOB. It is the same in my reference as well, 6.23E-8 or pK2=7.21 at 25C.
May 10, 2007

CHEMISTRY HELP PLEASE
when I use henderson-hasselbach Ka of HOP4^2- = 4.8 x10^-13 pKa= -lg(4.8 x10^-13)=12.3 substituting I get 7.44-12.3 = lg [base/acid] e^-4.86=[base/acid}= 7.75 x10^-3 according to my textbook this answer is incorrect and should be 0.59 Please Help! IF you are trying to work the...
May 10, 2007

Chemsitry II
mole fraction is equal to partial pressure divided by the total pressure Total pressure= sum of partial pressure use PV=nRT where n= number of moles equation become PV/RT=n make sure to convert the temperature to Kelvin and to use 0.0821 for R. V=volume, P=total pressure The ...
May 10, 2007

CHEMISTRY
pH= 7.44 What is the ratio of [H2PO4^-]/[HPO4^2-] What does the pH become if 25% of the hydrogen phosphate ions are converted to the dihydrogen phosphate ion? What does the pH become if 15% of the dihydrogen phosphate ions are converted to hydrogen phisphate ions? answered below.
May 10, 2007

CHEMISTRY
pH= 7.44 What is the ratio of [H2PO4^-]/[HPO4^2-] What does the pH become if 25% of the hydrogen phosphate ions are converted to the dihydrogen phosphate ion? What does the pH become if 15% of the dihydrogen phosphate ions are converted to hydrogen phisphate ions? Use the ...
May 10, 2007

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