Thursday

August 21, 2014

August 21, 2014

Total # Posts: 1,635

**o-chem**

Explain whether or not each of the following pairs of solvents might be useful as a solvent pair for recrystallization. (a) ethanol-methanol (b) hexane-cyclohexane (c) acetone-ethanol (d) water-ethanol (e) water-cyclohexane
*September 29, 2008*

**O- chemistry**

During a recrystalliztion experiment, a student allows the hot solution to cool to room temperature, then chills the solution in an ice bath. Is the student using correct recrystallization technique? Why does the student not simply chill the hot solution in an ice bath initially?
*September 29, 2008*

**AP US History**

1775 to 1800
*September 24, 2008*

**Re**

i need to find eveidence of 3 things that jesus did and 3 things jesus didn`t do. thanks!
*September 22, 2008*

**grammar**

What part of speech is the word "Below" used in the following sentence. Below the main level, we have a large playroom.
*September 16, 2008*

**education**

Just to take the very first term you've listed, are you suggesting that income is a characteristic of a multicultural school? What would that mean - that a multicultural school has income? And if so, is that what you're trying to say? I don't think it is, is it? Or...
*September 13, 2008*

**Calculus**

8/h -> infinity as h -> 0, so I don't see how the above expression can tend to anything other than minus infinity.
*September 12, 2008*

**Math**

Can I throw in a note of clarification? Melissa'a answers are actually correct: what's INcorrect is the algebra that apparently gave rise to them. As Bob pointed out, the "16 divided by 6" is actually a measure of inches per car, not cars per inch. Also, the ...
*September 10, 2008*

**algebra ll**

im having trouble with this problem 6( n - 4 ) = 3n
*August 26, 2008*

**Math**

No, I'm sure the problem is written like this: [(3a^3-27a)/(2a^2+13a-7)]/[9a^2/4a^2-1)] And to divide you multiply by the reciprocal. So i still don't get the problem I also know to factor, but I'm stil confused.
*August 7, 2008*

**Math**

No, I'm sure the problem is written like this: [(3a^3-27a)/(2a^2+13a-7)]/[9a^2/4a^2-1)] And to divide you multiply by the reciprocal. So i still don't get the problem I also know to factor, but I'm stil confused.
*August 7, 2008*

**Math**

I'm totally stuck on this problem!! Simplify: (2a^2+13a-7/3a^3-27a)(4a^2-1/9a^2)
*August 7, 2008*

**Algebra II/Trig**

No, Problem! Thank you so much for the answer!
*August 7, 2008*

**Algebra II/Trig**

Simplify: (n/4)/(n/m) As my answer I got: 4m Is this response correct? If not, please let me know what I did wrong.
*August 7, 2008*

**Math check**

No, you distributed the 4 to the y only. You also need to distribute the 4 to the 8. This would then make the answer 4y+32
*August 7, 2008*

**Math**

Simplify: 24w^7t^4/6w^9t^2 And How Exactly do u do this? I got 4w^16t^6
*August 5, 2008*

**Algebra II/Trigonometry**

Thank you so much drwls! I can not believe I did not figure that out!
*July 27, 2008*

**Algebra II/Trigonometry**

Simplify this problem: (1/2m^4n^5)^2
*July 27, 2008*

**English**

No. I think you should work the subject back in, in place of "it" and remove the "s" tacked on to the end of accomplishment
*July 27, 2008*

**math**

Can someone show me all the combinations possible with these things A B X Y LB RB LT RT L R U D
*July 26, 2008*

**math**

img59.imageshack.us/img59/4912/dsc00716qy7.jpg
*July 4, 2008*

**Physics**

A passenger on a train traveling 90km/h on a straight, level track notes that it takes another train (180 m long and moving with constant velocity) 4.0s to pass by. What is the velocity of that passing train relative to the ground? **please include explanation** thnx!!
*July 1, 2008*

**Chemistry**

Nope, Kristen is right. It can also be written as 4-methylpent-2-yne but it's the same thing.
*June 5, 2008*

**MAT 116 Algebra 1A**

V = 1/5 ð t^2 s
*May 26, 2008*

**Physics **PLEASE HELP****

plz ignore the 1st part just plz help with this: what's the relation between resistance and voltage?
*May 22, 2008*

**Physics **PLEASE HELP****

During a short circuit, why does the voltage go down? I know that the resistance is almost zero...but what's the relation between resistance and voltage?
*May 22, 2008*

**Geometry**

They are similar. because ALL triangles have and will always have 180 degrees. BOTH of the right triangles have an 90 degrees angle, which leaves 90 degrees left in both triangles than they have an another angle which is less than 90 (x degree) just by knowing this, you can ...
*May 2, 2008*

**Chemistry**

For the following electrochemical cell: Fe(s) | Fe2+(aq) || MnO4–(aq), Mn2+(aq) | Pt(s) Which letter corresponds to the correct balanced chemical equation in an acidic solution? A. 2Mn2+(aq) + 8H2O(l) + 5Fe2+(aq)-> 5Fe(s) + 16H+(aq) + 2MnO4–(aq) B. Fe(s)+8H+(aq)+...
*April 21, 2008*

**Chemistry**

For the following balanced equation: 2Ag+(aq) + Cu(s)<->Cu2+ (aq) + 2 Ag(s) Which letter corresponds to the correct cell notation at standard state conditions? A. Cu(s) | Cu2+(aq) || Ag+(aq) | Ag(s) B. Ag+(aq) | Cu2+(aq) || Cu(s) | Ag(s) C. 2Ag+(aq) | Cu2+(aq) || 2Ag(s...
*April 21, 2008*

**chemistry**

The first step of the synthesis is described by the reaction below. When 1.200 g of Fe(NH4)2(SO4)2 6H2O is mixed with 13 mL of 1.0 M H2C2O4 , the theoretical yield of FeC2O42H2O is grams. Fe(NH4)2(SO4)26H2O(s) + H2C2O4(aq)-> FeC2O42H2O(s) + (NH4)2SO4(aq) + H2SO4(aq) + 4 ...
*April 20, 2008*

**math**

Astro Knots
*April 17, 2008*

**chem**

H2 + H2O ->??
*April 15, 2008*

**chemistry**

Because solution pH is a measurement of either [H3O+] or [-OH] concentration, the acidic or basic nature of the acids and bases used in this experiment can be ascertained by inspecting just the density (electrostatic) potentials from the products (which contain either H3O+ or...
*April 14, 2008*

**Chemistry**

What does the density potential (also known as the electrostatic potential) measure? What do the colors on the images indicate?
*April 14, 2008*

**chemistry**

calculate the equilibrium constant for the reactionas written at 940K. NH4Cl->NH3+HCl delta H= NH4Cl -1779, NH3 -46, HCl -92 delta s= NH4Cl - 682,NH3 192,HCl 187 i dont know how to solve for the equilibrium constant without the concentration of the values???
*April 14, 2008*

**chemistry**

The standard solution of FeSCN2+ (prepared by combining 9.00 mL of 0.200 M Fe(NO3)3 w/1.00 mL of 0.0020 M KSCN) has an absorbance of 0.520. If a trial's absorbance is measured to be 0.275 and its initial concentration of SCN– was 0.00060 M, the equilibrium ...
*April 14, 2008*

**chemistry**

thanks
*April 10, 2008*

**chemistry**

The correct interpretation of the equation below is:? Fe3+(aq) + SCN¨C(aq)¡ú FeSCN2+(aq) A. The reaction is incomplete because the product is still charged. B. A heterogeneous equilibrium exists because of the charged ions. C. The equilibrium constant is Kc...
*April 10, 2008*

**chemistry**

the concentration of OH ions in a household ammonia cleaning solution is0.0035M. Calculate the concentration of H ions. would it be pH=-log (.0035)??? or Kc=1/.0035???
*April 10, 2008*

**chemistry**

If a solution is diluted, say by adding 100ml of solvent, does the number of moles of solute change? Does the concentration increase, decrease, or stay the same? i think it depends on what the solvent is, for example if its water then the concentration would decrease?? please ...
*April 10, 2008*

**Algebra 2**

A package with square ends has a combined length and girth (girth is the perimeter of a cross section) of 120 in. The surface area of the entire package is 3600 sq. in. Determine the dimensions of thr package. s in.*s in.*l in. one solution is: 11.08in*11.08in*75.68in. find ...
*April 8, 2008*

**chemistry**

how would i do something like this? Calculate the concentration of borate ion for each titration. Use the borate ion concentration to determine Ksp at each temperature.
*April 8, 2008*

**chemistry**

thanks soo much
*April 8, 2008*

**chemistry**

1)Does the solubility of borax in water increase or decrease as temperature increases? 2)Is the solvation of borax in water an exothermic or endothermic process? please help ive tried asking my ta but i cant understand him. he explains it through this weird process.
*April 8, 2008*

**chemistry**

Which of the following is NOT true of colligative properties? Colligative properties are... A. dependent on the mass of solute present. B. responsible for lowering the vapor pressure of a solution versus the vapor pressure of the pure solvent. C. independent of the chemical ...
*April 7, 2008*

**chemistry**

thanks sooo much
*April 7, 2008*

**chemistry**

When 18 g of ethylene glycol C2H6O2 is dissolved in 150 g of pure water, the freezing point of the solution is _C . (The freezing point depression constant for water is 1.86C kg) what i tried was 18/62 to find the moles. then i got .29/.150 to solve for the molality. then i ...
*April 7, 2008*

**chemistry**

thanks. sorry i go to ucla.hahaha
*April 7, 2008*

**chemistry**

Solid borax dissolves in water according to the equation: Na2B4O7 10H2O(s) 2Na+ (aq) + B4O5(OH)42–(aq) + 8H2O(l) The sign of Ssys will be A. positive B. negative because there are A. more B. less moles of products generated. i've tried solving this problem and i think...
*April 7, 2008*

**math riddle ALGEBRA WITH PIZZAZZ**

They are made for two wrists.
*April 6, 2008*

**Accounting Multiple choice**

ACON lTD ACQUIRES THE ASSETS AND ASSUMES THE LIABILITIES OF BIRD LTD WHICH HAVE OPEN MARKET VALUES OF A Assets $120,000 Liabilities $15,000 Acorn is to issue a debenture of $50,000 and 10,000 $1 Ordinary shares for the balance of consideration. What will be the credit to the ...
*April 3, 2008*

**math**

This cube has five cubes along each edge. The faces are covered, but the cube is hollow inside. Can it be divided into two pieces of equal volume? Explain. I am not sure what this question is asking? Does this look right? l x w x h= 5x5x5=125 125/2=62.5 Both sides have 62.5, ...
*April 2, 2008*

**chemistry**

d is the correct answer
*April 2, 2008*

**gr 7 math**

This cube has five cubes along each edge. The faces are covered, but the cube is hollow inside. Can it be divided into two pieces of equal volume? Explain. I am not sure what this question is asking?
*April 2, 2008*

**Calculus - Integrals**

I made this question, just wanted to make sure it didn't drown under the tide... I've set a problem up, something like this. s^4: A+D=0 s^3: -2A+B-3D+E=0 s^2: 2A-B+C+3D-3E=0 s^1: -2A+B-D+3E=4 s^0: A+C-E=4 Count Iblis -It's easier to substitute for s the values that...
*March 25, 2008*

**Calculus - Partial Integrals**

I'm confused. As soon as I get the so called 'Basic Equation,' I just don't know what to do after....
*March 25, 2008*

**Calculus - Partial Integrals**

The paragraph after the thing with s as a variable is copy and pasted from Count Iblis.
*March 25, 2008*

**Calculus - Partial Integrals**

I made this question, just wanted to make sure it didn't drown under the tide... I've set a problem up, something like this. s^4: A+D=0 s^3: -2A+B-3D+E=0 s^2: 2A-B+C+3D-3E=0 s^1: -2A+B-D+3E=4 s^0: A+C-E=4 It's easier to substitute for s the values that make the ...
*March 25, 2008*

**Calculus - Partial Fractions**

Would anybody mind showing it out? I tried what Count Iblis said, but it didn't really work out well...
*March 24, 2008*

**Calculus - Partial Fractions**

I'm sorry. I forgot to say that I don't know how to solve for A, B, C, D, and E... Help there would be appreciated.
*March 24, 2008*

**Calculus - Partial Fractions**

I've set a problem up, something like this. s^4: A+D=0 s^3: -2A+B-3D+E=0 s^2: 2A-B+C+3D-3E=0 s^1: -2A+B-D+3E=4 s^0: A+C-E=4
*March 24, 2008*

**Calculus - Integrals**

That's my problem. When I tried solving for A, B, C, D, and E in that first problem, it didn't really work out right...
*March 24, 2008*

**Calculus - Integrals**

1) A/x + B/(1+x) 2) A/x + B/x^2 + C/(1+x) I think I'm right....
*March 24, 2008*

**Calculus - Integrals**

I'm not quite sure about your explanation on Partial Fractions... And Liouville's Therom. We haven't done that in class... so...
*March 24, 2008*

**Calculus - Integrals**

I have 3 questions, and I cannot find method that actually solves them. 1) Integral [(4s+4)/([s^2+1]*([S-1]^3))] 2) Integral [ 2*sqrt[(1+cosx)/2]] 3) Integral [ 20*(sec(x))^4 Thanks in advance.
*March 24, 2008*

**Calculus - Integrals**

Could you expand on #1 a bit more? I tried Partial Fractions, but I couldn't get a definite answer...
*March 23, 2008*

**Calculus - Integrals**

I have 3 questions, and I cannot find method that actually solves them. 1) Integral [(4s+4)/([s^2+1]*([S-1]^3))] 2) Integral [ 2*sqrt[(1+cosx)/2]] 3) Integral [ 20*(sec(x))^4 Thanks in advance.
*March 23, 2008*

**critical thinking**

premise--terrorists attacks of September 11, 2001, produced a response among American officialsm the media and public conclusion--matched only by the attack on Pearl Harbor
*March 20, 2008*

**APA FORMATTING**

I think it's C. Am I right? When using APA, which of the following describes the method in which a work without page numbers should be presented in in-text citations? A. No mention of the page number is required in APA B. If no page number is present, it is not a credible ...
*March 19, 2008*

**English**

I think it's a, but document formatting messes me up a little :) Any help would be great, and much appericated When citing a source within the body of your essay, what must be included after the quotation marks at the end of the sentence (when the author’s name has ...
*March 19, 2008*

**Geography AS level**

why are waterfalls tempary features
*March 18, 2008*

**Oceanography**

What are the steps and timing of the whales, dolphins, porpoises evolution.
*March 13, 2008*

**Oceanography**

How did the extinction of the Mesozoic marine megafauna allow evolution of cetaceans?
*March 13, 2008*

**Business Ethics**

In the case study of Geletx, what should Jed do? Is this a violation of FAPA?
*March 12, 2008*

**Social studies**

all I need to know is is it hudusim or Buddism?
*March 8, 2008*

**Social studies**

of Hindusim and Buddhism which has a definite indentifiable start?
*March 8, 2008*

**Social studies**

What is the climatic issue that significantly influences the Indian subcontinent?
*March 8, 2008*

**social studies**

What architectural wonder was completed in 1648?
*February 28, 2008*

**engineering physics 2**

A 19 m long piece of wire of density 8.34 g/m3 has a diameter of 12.593 mm. The resistiv- ity of the wire is 1.7e-8(ohm)(m) at 20 degrees celsius. The temperature coefficient for the wire is 0.0038(degrees celsius)^-1. Calculate the resistance of the wire at 20degrees Celsius...
*February 28, 2008*

**chemistry**

2Al+3Cl2=2AlCl3 calculate the amount(number) of excess reagen units remaining when 4.03x10^23 Al atoms and 6.42x10^23 Cl2 molecules react? please help!!!!! thanks
*February 23, 2008*

**french**

does any one know the french meaning of la nouvelle .
*February 23, 2008*

**year 7 french**

i need to translate countries written in french into english . does anyone know if there are any good sites that will help me. thanks
*February 23, 2008*

**math**

I tried to answer this but i don't know if i am even close. I included my work .Thanks. The island's travelling sales monkey is selling gold watches that washed up on the beach. The islanders use green stones, pink clamshells and ox horns for money.Sixty-two green ...
*February 13, 2008*

**grade 7math**

The island's travelling sales monkey is selling gold watches that washed up on the beach. The islanders use green stones, pink clamshells and ox horns for money.Sixty-two green stones have the same value as 17 ox horns and 258 pink clamshells have the same value as 89 ...
*February 13, 2008*

**Economics**

In running a regression model with three variables, two of the three come back as statistically significant at the 95% level of confidence. The one that doesn't is the intercept - so is my model still valid?
*February 9, 2008*

**math**

Thanks so much.I worked on this while i was waiting and ended up doing it backwards from you but got the same answer. 150+6=156 156/13=12 364+26=390 390/13=30 60+5=65 65/13=5 60 is the common multipler, so i got 60 days. Is this still right?
*February 6, 2008*

**math**

I really don't know where to start or what stratedgy to use.
*February 6, 2008*

**math**

Days on Planet Red are 13 hours long. The animals on Planet Red have regular eating and sleeping habits. The silver snake sleeps for 150 hours, eats for 6 hours, then goes back to sleep. The green walking fish sleeps for 364 hours, eats for 26 hours and then goes back to sleep...
*February 6, 2008*

**Physics**

Can I use P1/P2=(T1/T2)y/y-1 to find the temperature when we pressure liquid refrigerant, for example liquid propane?
*February 6, 2008*

**Physics 11**

The brakes on a car permit it to decelerate at the rate of -8.0m/s^2. How much distance is required to stop this car when it is travelling 60.0km/hr? The answer given is 173.6m I solved it this way 60km/h = 16.667m/s A=V/T 16.667m/s / -.80m/s^2 = 20.834 seconds D=RT 16.667m/s ...
*February 6, 2008*

**History**

Yea i thinks its D also... all the other answers are not as good, so im goin with that Palmer. Page 462 is what ive found Right under the purple section...
*February 2, 2008*

**Chemistry**

A 15.0g sample of liquid ethanol, C2H5OH, absorbs 5.13x10^3 J of heat at its normal boiling point, 78.0C. The molar enthalpy of vaporization of ethanol is 39.3kJ/mol. (a) What volume of ethanol vapor is produced? The voume is measured at 78.0C and 1.00atm pressure. (b) What ...
*January 27, 2008*

**social health**

I want a picture of social health
*January 23, 2008*

**science**

how does a magnet attract a paperclip ?
*January 7, 2008*

**Chemistry**

If I have 1.27 cm^3, how do I convert into picometers?
*January 2, 2008*

**Chemistry**

Metallic sodium adopts a body-centered cubic structure at 25 degrees C and 1 atm. The density of sodium under these conditions is 0.97 g/cm^3. What is the unit cell length?
*January 2, 2008*

**math**

haylee is geting a job for moing lanws her dad lowns her 190 dollars to by a lawn mower. when she startes she is in depth 190 dollars. in week two she is in depth 70 dollars. how did she get to be depth 70 dollars
*December 16, 2007*

**Chemistry**

Use the equation, PV = nRT n = 3mol T = 273K P = 101.325kPa = 1atm R = .08206L•atm/K•mol Solve for V
*December 10, 2007*

**Calculus**

The question is, if f(x) is equal to the series from n to infinity of a sub n times (x-7)^n for all n, find a formula for a sub 10. (I apologize for typing it out in the way that I did, but it was the only way I could. I don't quite understand what is being asked here. I ...
*December 10, 2007*

** math mesurment**

how many grams in a pound
*November 26, 2007*

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