Posts by Chem

Total # Posts: 138

PHySICS
A rod 14.0 cm long is uniformly charged and has a total charge of -22.0 μC. Determine the magnitude and direction of the electric field along the axis of the rod at a point 36.0 cm from its center. ans:E = 1.59e6 N/C, pointing to the left equation:k_e(Q/L)(1/a-(1/(L+a))) ...

Intro Chemistry
oh thanks I get it now..

Intro Chemistry
tried using M1V1=M2V2 but without sucess

Intro Chemistry
_______g of MnSO4 H2O are needed to prepare a solution of 100.00mL of 0.100 M MnSO4. Thank You

Oxidation State
Give the oxidation sate for the monoatomic cobalt species whose electron configuration is the following:[Ar]4s0 3d6 Is the answer +3? Thank you!

Intro Chemistry
Thank you, I guess I got confused with Al and As :)

Intro Chemistry
I am reviewing my test and I having trouble figuring out the answer to the following question: List the following element symbols in order of decreasing exothermic electron affinity: Al, Ca, As _______>________>________ I wrote: Al>As>Ca (I got it wrong) I know ...

GenChem II
What mass of CsBr must be added to .500L of water to produce .4molality solution? What are mole fraction and mass percent? Here is my work and below I will post a question about it: 1 mol CsBr = 212.81g density of water = 1g/mL d=mv 1=x/500 x=500g of water --> solvent ....

Organic chemistry
How many grams of water would it take to quench 1 g of phenylmagnesium bromide?

Organic Chemistry
N-methylbutanamide

bobpursley plz check
i m getting 9.77 g for Bi2S3 . no limiting reactant .. both are same .. can u plz conform

Chemistry - Urgent
Determine the mass of 3.18 ×1023 atoms Cl.

Chemistry
Can you repost #1 please. Thanks.

Chemistry
1) How many drops of 12M HCl would you add to 1.00 L of 0.100 M HC2H3O2 to make [C2H3O2-] = 1.0 x 10^-4 M? Assume that 1 drop = 0.050 mL and that the volume of the solution remains 1.00 L after the 12 M HCl is diluted. [Hint: What must be the [H3O+] in the solution?] 2. What ...

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I'm sorry I made a typo it goes through a solution of Al(NO3)3 and that's why I mutliplied the m.w. of Al by 3 because you have 3 moles of Al per NO3

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What mass of Al can be deposited by the passage of a constant current of 5.00 A through a Al(NO3)2 solution of 2.00 hours? My work: Q= I*t = 5 * 7200sec = 36000 36000/96458= .3732 .3732* 1/3 * (26.98*3) = 10.06g But this is wrong it's suppose to be 3.3.6g. why is that?

chemistry
thanx alot =)

chemistry
Consider a system consisting of a cylinder with a movable piston containing 10^6 gas molecules at 298K at a volume of 1L. Consider the following descriptions of this system: 1. Initial system 2. Starting from the initial system, the volume of the container is changed to 2L and...

CHEMISTRY
thanx a tons =)

chem help
ok thanks alot... the PartB asks for: What is the percent ionization of ammonia at this concentration?

chem help
sorry the 2nd question is the right one

chem help
Ammonia,is a weak base with a Kb value of 1.8x10^-5 .What is the pH of a 0.22M ammonia solution?

chem help
Ammonia,is a weak base with a Ka value of 1.8x10^-5 .What is the pH of a 0.22M ammonia solution?

chem help
You need to produce a buffer solution that has a pH of 5.08. You already have a solution that contains 10 mmol (millimoles) of acetic acid. How many millimoles of acetate (the conjugate base of acetic acid) will you need to add to this solution? The of acetic acid is 4.74.

chem
I DON'T GET WHATS DONE.. DR.Bob22 - could u please explain this again..thank u

density of Magnesium!
To find the volume of a HCP structure given the height and the lenght, you should use this formula: l^2*h*((3)^1/3)/2)

Chem
so wat do i do?

Chem
complete and balance the following decompition equations CaCO (heated) --> 3 please tell me how to do this and what exactly is suppose to be going through my head while doing this. I can balance these equations with no problem I just have no idea what to do...

Chemistry
How many atoms are there in 6.90 moles of sulfur (S)? Calculate the molar mass of a compound if 0.411 mole of it has a mass of 185 g. Know of any good sites that help answer these ? Or information on how to?

chem
E is NOT NOT NOT THE ANSWER!!!!

chemistry
Does the element sodium have properties in common with NaCl? Explain

chemistry
Which of the following subshells is correctly designated? a. 1f5 b. 3s3 c. 6f12 d. 4d11 e. 1p2

chemistry
Which of the following subshells is correctly designated? a. 1f5 b. 3s3 c. 6f12 d. 4d11 e. 1p2

Dan
N2 + 3H2 --> 2NH3 At 25°C (delta)Ho = -92.22 kJ and (delta)So = -198.53 J/K. Using this information, calculate the equilibrium constant for the reaction at 2.43x10^2°C. (R = 8.314 J/K) Apparently the way I'm doing it is wrong: I divide 198.53 by 1000 then ...

BIOCHEMISTRY
calculate the pOH of 3X106-6M of HF

BIOCHEM
calculate the pH of 0.0076M KOH

chem!
Calculate the heat of reaction for the incomplete combustion of 67.0g propane producing carbon monoxide gas and water vapour. how would I go about and do this question? What are you studying? Do you know how to use the thermodynamic tables (delta Ho, etc). delta Hrxn = delta ...

question
whats relationship between temp and kinetic energy http://www.google.com/search?as_q=temperature+kinetic+energy+&hl=en&num=10&btnG=Google+Search&as_epq=&as_oq=&as_eq=&lr=&as_ft=i&as_filetype=&as_qdr=all&as_nlo=&as_nhi=&as_occt=title&as_dt=i&as_sitesearch=&as_rights=&safe=images

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