Monday
October 20, 2014

Posts by Mima


Total # Posts: 37

Physics
A 80.0 Hz generator with an rms voltage of 150 V is connected in series to a 3.20 k ohm resistor and a 3.50 micro farad capacitor. Find the phase angle between the current and the voltage.
March 2, 2013

physics
a block of mass m=0.9 kg is connected to a spring of force constant k= 775 N/m on a smooth horizontal surface. plot the potential energy of the spring from x= -5 cm to x= 5 cm. determine the turning points of the block if its speed at x= 0 is 1.2 m/s.
October 7, 2012

physics
A soccer ball is kicked from the ground with an initial speed of 14.5 m/s. After 0.272 seconds, ts speed is 12.4 m/s. (A) Give a strategy that will allow you to calculate the ball's initial direction of motion. (B) Use your strategy to find the initial direction.
September 16, 2012

Chemistry
Neat pure ethanol C2H5OH has an enthalpy of vaporization of 39.3 Kj/mol, and a vapor pressure of 0.308 atm at 50 C. What is the boiling point, at atmospheric pressure of 1 atm, of a solution consisting of 35 G of phenol (a non-electrolyte hydrocarbon with a molecular formula ...
April 30, 2012

Chemistry
Got it, you are right, it's 0.439. Thank you so much, I was doing an easy math mistake (substracting before multiplying). Thanks again.
April 29, 2012

Chemistry
E= 0.438? I got the same answer (1.987) when I used the numbers you mentioned. Is the E standard potential = -0.26 -(-0.76)? Am I doing that right?(its cathode-Anode) right?
April 29, 2012

Chemistry
Calculate the cell potential for the following reaction as written at 79C given that [Zn^+2] = 0.819 M and [Ni^+2] = 0.014 M. Zn + Ni^+2 = Zn^+2 + Ni I know: E=E -RT/nF ln Q reduction potential for Ni= -0.26 reduction potential for Zn = -0.76 so E standard potential = 0.5 E= 0...
April 29, 2012

chemistry
I'm getting 8.355E-22 Kg on for reactants, and 8.322E-22 Kg for products. I multiplied each mass they gave us in amu by 1.661E-27 to get it in Kg.
April 28, 2012

chemistry
For the following fusion reaction, Calculate change in energy per mole.( Answer in J/mole) 2H1 + 2H1 ---> 3H1 + 1H1 (the mass number is in front of the atom and the atomic number is behind the atom) Given info:Atoms with their masses(amu) H-1 1.00782 H-2 2.01410 H-3 3.01605...
April 28, 2012

Chemistry
Thanks, I got it right.
April 27, 2012

Chemistry
The hint they gave us now is that this is a first intigrated order reaction, I do not get it, what the order of the reaction has to do with nuclear chemistry and decay?
April 27, 2012

Chemistry
I thought about that, but didn't know the initial and remaining N. Why initial N is 100?
April 27, 2012

Chemistry
A fossil is found to have a C-14 level of 86% compared to living organisms. How old is the fossil?, (the half life of C14 is 5730 years).
April 27, 2012

Chemistry
Thank you so much.
April 24, 2012

Chemistry
carbon 14 has a half life of 5715 years. If you start with a 5 gram sample of 14C, what mass is left after 15,000 years?
April 24, 2012

chemistry
Spectrophotometer. 2 ml of NH3 is added to Cu(NO3)2 to give it dark blue color. If we accidantely put 3 ml of NH3, would the absorbance reading by spec should be considered? Explain. I wrote we shouldn't consider the reading because it will give darker color than it should...
April 23, 2012

chemistry
Why the addition of NH3 should be precise in spectrophotometer reading? What if it gives darker color?
April 23, 2012

Chemistry
Thank you for your reply.
April 19, 2012

Chemistry
Our professor just told us that the final exam will be the ACS exam, we are taking general Chemistry II. What is the best way to study for ir? Is the preparing for ACS general chemistry study guide good? If we are taking general Chemistry II do we have to study Chemistry I again?
April 19, 2012

Chemistry
Our professor just told us that the final exam will be the ACS exam, we are taking general Chemistry II. What is the best way to study for ir? Is the preparing for ACS general chemistry study guide good? If we are taking general Chemistry II do we have to study Chemistry I again?
April 19, 2012

Chemistry
In the lab, as acid concentration got decreased, the Ka got increased. Why ?
April 15, 2012

chemistry
Thanks, you mean finding n for acid or base? The graph represent only PH and volume we added for acid or base in ml.
April 14, 2012

chemistry
We had a Chemistry lab for buffer system, we used HCl and NAOH. We did a graph ( PH vs ml of HCL and NaOH, we told to estimate the buffer capacity using the graph. How to do this?
April 14, 2012

math
the sum of the digits of a two digit prime number is substracted from the number. prove that the difference cannot be a prime number.
April 12, 2012

math
when jason arranges his toy soldiers in rows of 6, he has left 1.when he arrahges them in rows of 8, he has 3 left over. when he arrenges in rowsof 10 then 5 left over. what is the smallest possible number of toy soldiers that jason plays with/
April 11, 2012

chemistry
Thanks a lot, I got it.
April 7, 2012

chemistry
Thank you so much for replying, but I can't understand how to solve for partial pressure of CO2, when I get the [H^+] from PH then how to solve for partial pressure of CO2?
April 7, 2012

chemistry
carbon dioxide dissolves in water to form carbonic acid. Estimate the thermodynamic equilibrium constanst (K) for this reaction (delta Gf values: H2CO3= - 616.1, H2O= - 237.1, CO2= - 394.4) . Carbonic acid then ionizes in water (Ka1= 4.5 x 10^-7). Ignoring Ka2, estimate (K) ...
April 7, 2012

Chemistry
A- a water soluble salt forms a precipitant during Group 3 analysis. An acidic solution of this precipitant and NaBiO3 yields a pinkish color. This same salt has no reaction to concentrated H2SO4 or AgNO3, what is the chemical formula for this salt? B- a brown colored salt ...
April 3, 2012

Chemistry
A- a water soluble salt forms a precipitant during Group 3 analysis. An acidic solution of this precipitant and NaBiO3 yields a pinkish color. This same salt has no reaction to concentrated H2SO4 or AgNO3, what is the chemical formula for this salt? B- a brown colored salt ...
April 2, 2012

Chemistry
You are right, thank you so so much. With addition of HCl, the Ph= -0.052. With addition of NAOH, the PH= 0.052. Thank you for all your efforts.
March 27, 2012

Chemistry
I got initial PH= 9.24 PH after HCl addition= 9.19 PH after NaOH addition= 9.3 so delta PH after HCl= 0.05 delta PH after NaOH= - 0.06 all these still wrong answers. could it be that I'm calculating the total volume wrong? should be 0.01+0.006 L?
March 27, 2012

Chemistry
Still wrong answer.
March 27, 2012

Chemistry
I did it in moles but still the homework assignment website is not accepting these answers. My work: Initial PH = 9.24. moles of NH3= 0.01 moles of NH4= 0.01 After addition of HCl: moles of HCl added= 0.0006 moles of NH3 left= 0.0094 moles of NH4= 0.0106 PH= 9.19 Addition of ...
March 27, 2012

Chemistry
Calculate the change in PH when 6 ml of 0.1 M HCl is added to 100 ml of a buffer solution that is 0.1 M in NH3 and 0.1 M in NH4Cl. And calculate the change in PH when 6 ml of 0.1 M NaOH is added to the original buffer solution.
March 27, 2012

Chemistry
Calculate the change in PH when 6 ml of 0.1 M HCl is added to 100 ml of a buffer solution that is 0.1 M in NH3 and 0.1 M in NH4Cl. And calculate the change in PH when 6 ml of 0.1 M NaOH is added to the original buffer solution.
March 27, 2012

history
don't know don't care.. Research it urself. people are to lazy to do homework by themselvevs. Don't answer this question it is a portfolio that you are supposed to do by urself..
December 27, 2006

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