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April 16, 2014

Search: chemistry help !!!!!!!!!!!!!!!!

Number of results: 208,048

HELP
Calculate the change in energy when 665.0 g of CH3OH(g) completely reacts at a constant temperature of 300 K and constant pressure of 0.95 atm. R = 8.314 J/mol*K and R = 0.08206 atm*L/mol*K So i used the formula change in energy = change in H - nRT 90.7-51.9-38.8 its wrong i ...
Thursday, January 27, 2011 at 6:40am by Chemistry

chemistry help
out of the pairs of orbitals which has a higher amount of energy 4f or 6s
Friday, December 30, 2011 at 10:44pm by chemistry

ChEMISTRY (Help please)
discuss the kinetic theory of gases and proof that the equation pv =1/3 mv2
Tuesday, April 13, 2010 at 8:02pm by chemistry

CHEMISTRY
Thank you for the help!
Sunday, April 6, 2014 at 12:12pm by Chemistry

Lauren
correct thank you for the help
Wednesday, November 14, 2007 at 11:01pm by Chemistry

Curious Maria
could help but i can't find that diagram ur talking about
Wednesday, May 28, 2008 at 8:54pm by Chemistry

Chemistry
Nevermind I figured it out with your help. The answer was 2.94. Thank you so much!
Wednesday, February 11, 2009 at 8:07pm by Chemistry

gen chem
thanks for the help but im still not getting the right answer
Sunday, May 9, 2010 at 5:54pm by chemistry

muah
explain why the name of the insect millipede doesnt follow SI conventions? please help me i cant find this any where in my text. I would be very happy if you did help. :D
Sunday, September 26, 2010 at 8:26pm by Chemistry

chemistry
what does an atom of lead look like? what are the parts that compose of the atom? help me pls
Monday, September 3, 2007 at 4:22pm by chemistry

Suzy
Can some one read my lab report for me... I have it almost finished.. I just need help on the discussion part Please
Friday, November 16, 2007 at 6:35pm by Chemistry

CHEMISTRY
Thank you! .434^5 / .0786^6 equals .653, that is correct! I was just able to answer another problem similar to this thanks to your help. Many thanks!
Sunday, April 6, 2014 at 12:11pm by Chemistry

PLZ look at Chemistry Questions!!!
My questions are now on page two, you answered more recent questions and not the ones that have been posted longer....sorry to be a nag but I need help!
Monday, December 6, 2010 at 4:29pm by Chemistry!

Chemistry
A solution of AuCl- is mixed with a solution of Sn2+ under standard conditions. What is the equation? the answer is 2AuCl4- + 3Sn2+ -> 3Sn4+ + 2Au + 8Cl- how do i get this? ITS desperate... plz help me! THANK_YOU SO MUCH!
Thursday, June 14, 2012 at 9:37pm by Chemistry

Chem
Directions: Use the principles of atomic structure and/or chemical bonding to explain each of the following. In each part, your answer must include references to both substances. Problem: The carbon-to-carbon bond energy in c2h4 is greater than it is in c2h6. Any help is ...
Monday, November 19, 2007 at 9:03am by Chemistry

CHEMISTRY
PartA: Ammonia,is a weak base with a Ka value of 1.8x10^-5 .What is the pH of a 0.22M ammonia solution? PartB: What is the percent ionization of ammonia at this concentration? I got the answer for PartA which is pH=11.3. but i cant slove PartB..HELP!!!
Monday, March 2, 2009 at 7:34pm by CHEMISTRY

Chemistry Octane Combustion
Write the balanced equation for the combustion of octane (C8H18). Assuming that gasoline is 100% octane, with a density of 0.692 g/mL, what mass of CO2 is produced by combustion of 1.7 1010 gal of gasoline? Need help on how to get started, I have the balanced equation...
Tuesday, September 15, 2009 at 6:45pm by Chemistry

Suzy
ALSO PART OF THE DISCUSSION In Figure B the line of y=0.0052x-6E-05, R^2 .9989 the .9989 is really close to 1, the closer to one the better, to go over one seems to make the lab a failure. Less than one must mean that the lab went well and was done correctly. COULD YOU HELP ME...
Friday, November 16, 2007 at 6:35pm by Chemistry

REETA
A 2.10 mol sample of oxygen gas is confined to a 5.10 L vessel at a pressure of 7.99 atm. Find the average translational kinetic energy of an oxygen molecule under these conditions in (j/mol) When i was working this out i tried using pv=nrt to find the temperature which i got ...
Tuesday, October 21, 2008 at 5:28pm by CHEMISTRY

Chemistry
so i got a test and like usual my teacher didn't teach me half of the stuff that's going to be on it so he gave us a pretest of what is going to be on it and an answer key and i got several questions 13.) what is the pH of a formic acid if the concentration is .00055 M? ok so ...
Tuesday, April 7, 2009 at 9:04pm by Chemistry

Suzy
Discussion: This experiment was conducted to identify the iron content in a breakfast cereal. The results indicate that there was iron in the chosen breakfast cereal of Kix, the spectrometer shows that the absorbance or color was around .39 so about 39% as seen in Figure A the...
Friday, November 16, 2007 at 6:35pm by Chemistry

Suzy
Discussion: This experiment was conducted to identify the iron content in a breakfast cereal. The results indicate that there was iron in the chosen breakfast cereal of Kix, the spectrometer shows that the absorbance or color was around .39 so about 39% as seen in Figure A the...
Friday, November 16, 2007 at 6:35pm by Chemistry

ChemChem
Hi, please help! Question: Farmers added Calcium hydroxide to soil one morning. They then planned to add Ammonium chloride fertilisers to the soil immediately. However, the instruction label on the packet of fertilisers read: "Do not add fertiliser immediately after adding ...
Monday, November 2, 2009 at 4:29am by Chemistry

Chemistry
Sorry about that The chemical 5-amino-2,3-dihydro-1,4-phthalazinedione, better known as luminol, is used by forensic scientists in analyzing crime scenes for the presence of washed-away blood. Luminol is so sensitive that it can detect blood that has been diluted 10,000 times...
Wednesday, February 11, 2009 at 7:22pm by Chemistry

Chemistry
Do you think you know how to figure out this one: Sorry about that The chemical 5-amino-2,3-dihydro-1,4-phthalazinedione, better known as luminol, is used by forensic scientists in analyzing crime scenes for the presence of washed-away blood. Luminol is so sensitive that it ...
Wednesday, February 11, 2009 at 8:07pm by Chemistry

Jim
I need some help with calculating percent yield and percent purity of aspirin. Here's my data (questions follow): SYNTHESIS Mass of salicylic acid.., 2.0 g Volume of acetic anhydride.., 5 mL Mass of watch glass.., 22.10 g Mass of aspirin and watch glass.., 28.01 g Mass of ...
Saturday, March 24, 2007 at 12:37am by Chemistry

Suzy
Introduction: This report discusses an experiment to study the percent mass of iron determined by the concentration of a colored iron solution from the absorbance of the spectrometer. This lab is designed to tell the content of iron in cereal, usually food products list iron ...
Friday, November 16, 2007 at 6:35pm by Chemistry

CHEM HELP
what is the theoretical mole ratio- NaCl to NaHCO3 How do you determine the percentage error of an experimental mole ratio It would be easier for us to help you if we had the entire problem instead of just parts of it. However, from the standpoint of Na, the mole ratio of NaCl...
Tuesday, January 2, 2007 at 6:26pm by CHEMISTRY HELP

chemistry
What [I^-]should be maintained in KI(aq) to produce a solubility of 1.910−5mol PbI2/L when PbI2 is added?
Monday, March 9, 2009 at 7:37pm by CHEMistry help

chemistry
What [I^-]should be maintained in KI(aq) to produce a solubility of 1.910−5mol PbI2/L when PbI2 is added? (sorry i cant find it under the posted questions )
Monday, March 9, 2009 at 7:51pm by CHEMistry help

Chemistry
this still gives me the wrong answer =( plz help..
Saturday, March 14, 2009 at 10:03pm by CHEMistry help

Can someone Please Help
Chemistry
Monday, February 4, 2013 at 10:09pm by Greg

Psychology Please Help!!
a. the norms upon which the test was developed did not reflect her background.
Thursday, November 17, 2011 at 11:52pm by Chemistry Chick

Psychology Please Help!!
UR CORRECT
Friday, November 18, 2011 at 12:06am by Chemistry Chick

Jude
When you do the -log of 2.50 you get a negative number, so I am not really sure what you do with that, do you not use the pKa for anything?
Thursday, February 12, 2009 at 7:46pm by Chemistry! Please Help!

Jill
State the relationship of A to B (i.e. <, >, = or can't be determined). 1. Using a 0.05 M Ag+ titrant A.VEP in titration 25-mL of 0.01 M MgCl2 B.VEP in titrating 25-mL of 0.01 M AlCl3 2. A 25.0-mL solution contains 0.015 M NaCl and 0.010 M HCl A.VEP (Mohr) B.VEP (...
Monday, February 20, 2012 at 6:33pm by Chemistry Homework Help

General Chemistry
Silver chloride has a larger Ksp than silver carbonate. Does this mean that AgCl also has a larger molar solubility than Ag2CO3?
Monday, April 23, 2012 at 11:31pm by Chemistry help needed

chemistry
Thanks for you help.
Monday, February 10, 2014 at 11:16pm by solution chemistry

chemistry
please help.....i want to know the metals that have atomic mass less than50 with symbol and valency
Wednesday, May 25, 2011 at 2:41pm by mystery/chemistry

9th grade chemistry
oh ok but that still doesn't really help because they do not provide the equation in the chem review book they distributed to us.
Monday, March 29, 2010 at 5:21pm by chemistry challenged

9th grade chemistry
lol well have you seen my name?? i cant do this... i figured out other equations but i dont know why i cant figure this one out... oh well i just ask other people to help me because i need someone to show me how to do it right infront of me but thank you for all of your help...
Monday, March 29, 2010 at 5:21pm by chemistry challenged

Chemistry
Calculate the concentration (% W/V) of NaCl solution that was made by dissolving 15.0 g of sodium chloride in enough water to make 300.0 mL of solution. Okay the answer is 5.00%....however I keep getting 0.0500%....Why? and which one is the correct answer? Thanks for your help...
Saturday, October 29, 2011 at 4:30pm by Chemistry Chick

chemistry
use your conversion factors to determine grams to mols and then use mols of cl- per solution to convert
Tuesday, October 23, 2007 at 10:13pm by Help

Chemistry
How would you find the Kb of a weak base??
Monday, April 7, 2008 at 10:06pm by HELP!!!

chemistry
Calculate the value of the equilibrium constant (Kc) for the reaction shown, if SbCl5 was found to be 5.57% decomposed at 521K when its initial concentration was 7.60M. SbCl5 <==> SbCl3 + Cl2
Saturday, April 19, 2008 at 9:56pm by help!!

chemistry
oh sorry, all of them are in gaseous states
Saturday, April 19, 2008 at 9:56pm by help!!

chemistry
How do i figure out the electron configuration of Fe(C2O4)3^3- ?
Tuesday, April 22, 2008 at 12:31am by help!!

chemistry
Calculate the equilibrium constant for the weak acid, CH3CH2CO2H, if the aqueous solution of CH3CH2CO2H that has an initial concentration of 1.97E-2 M has a [H+] of 5.00E-4. CH3CH2CO2H <=> CH3CH2CO2 + H i know that to figure out the equilibrium constant it is kc = ...
Thursday, April 24, 2008 at 8:14pm by help!!

Chemistry
What is the products for HCl + Na2S04 + BaCl2?
Monday, November 10, 2008 at 4:26pm by Help

Chemistry
Why doesn't it enter the reaction?
Monday, November 10, 2008 at 4:26pm by Help

Chemistry
The complete combustion of 0.100 mol of CH4 in oxygen in a bomb calorimeter caused the water of the calorimeter to rise in temperature from 25.00 degrees Celsius to 37.70 degrees Celsius. Suppose that the combustion of the 0.1 mol of CH4 was instead run at constant pressure (1...
Friday, February 6, 2009 at 12:34am by HELP!!!

chemistry
Lead metal is added to 0.100M Cr3+(aq) Pb(s) + 2Cr3+(aq) -> Pb2+(aq) + Cr2+(aq) What is [Pb3+] when equilibrium is reached? What is [Cr2+] when equilibrium is reached? What is [Cr3+] when equilibrium is reached? i solved it buh for sum reason am not getting d correct answer...
Monday, February 9, 2009 at 9:11pm by help!!!

chemistry
initail 0.120M 0M 0M change -2X X 2X equilbrium (0.120-2X) X 2X Kc= [Pb^2+] [Cr^2+]/ [Cr3+] 3.2x10^-10 = 4x^3/ (1.20-2x_^2 x= 1.048x10 ^-4 n thn i kno i hv 2 substitude in 'x' im jus hving probs wid the calculation part..plz help asap..as tis stuff is due 2moro in d morning......
Monday, February 9, 2009 at 9:11pm by help!!!

chemistry
im still not getting the answer right!!! =( n it ws my mistake...the concentration is 0.120M
Monday, February 9, 2009 at 9:11pm by help!!!

Chemistry
Hi! I'm in chem class and I don't know the answer to these questions I have several metal alloys and have to tell their general elements that make them up for example bronze - copper and tin What is the elements that make up Pewter? Also I was woundering if someone can tell me...
Tuesday, March 10, 2009 at 9:24pm by HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Chemistry
exactly it dosne't make any senst at all lol... thanks for the help see it's just public high school chemistry... Let's put it this way after taking AP World history just regular public high school chem seems like a waste of time... What we do in two weeks in that class AP ...
Tuesday, March 10, 2009 at 9:24pm by HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Chemistry
I think in order to answer the dissolving rates I need to know the formulas to find dissolving rate not just some arrows and stuff thata leaves me just knowing what happens but knowing why lol stupid publich high school
Tuesday, March 10, 2009 at 9:24pm by HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

chemistry
Calculate [Fe^2]+ when the cell reaction reaches equilibrium? A voltaic cell is constructed based on the following reaction and initial concentrations: Fe^2+,( 0.0050 M ) + Ag+,( 2.5 M ) ----> Fe^3+,( 0.0050 M ) + Ag(s)
Saturday, March 28, 2009 at 10:49pm by HELP!!!

chemistry
A voltaic cell employs the following redox reaction: Sn^2+(aq)+ Mn(s)--> Sn(s) + Mn^2+(aq) Calculate the cell potential at 25 under each of the following conditions. a.)[Sn]= 1.51E-2 M [Mn]= 2.52M b.)[Sn]= 2.52 [Mn]= 1.51E-2 M
Sunday, April 19, 2009 at 9:56pm by help

chemistry
That is 25 degree celsius
Sunday, April 19, 2009 at 9:56pm by help

chemistry
Thank you
Sunday, April 19, 2009 at 9:56pm by help

CHEMISTRY
The atmosphere contains about 6.81013 moles of ozone. If this amount of ozone gas is compressed into a thin layer around the globe (the radius of Earth is 6370 km) at STP (Standard Temperature (0C) and Pressure (1.0 atm.)), how thick will the layer be in millimeter? One ...
Friday, March 5, 2010 at 3:10pm by HELP!!!!!

Chemistry
Problem: In a first order decomposition reaction, 50% of a compound decomposes in 10.5 minutes. What is the rate constant of the reaction? The solution my professor gave says: k = .693 / 10.5min Where did the .693 come from? Thanks
Monday, March 15, 2010 at 6:17pm by Help

Chemistry
Why is it important to use liquids with relatively lower boiling points when using the Dumas method?
Thursday, April 1, 2010 at 10:56am by Help

Chemistry
How do you determine the moles of just NaCl? and is the moles of HCl and NaOH just the molar mass? Thanks
Thursday, April 1, 2010 at 10:55am by Help

Chemistry
How would the pH differ for a 0.1M solution of NaHCO3 vs 0.2M NaHCO3 - remain the same, double, half,or can't be calculated without Ka or Kb?
Tuesday, April 13, 2010 at 9:51pm by HELP

Chemistry
is this because this acts as a polyprotic acid, or because the ratio in the Henderson Hasselbach for HA/A- remains the same?
Tuesday, April 13, 2010 at 9:51pm by HELP

Chemistry
question from my previous post answered by DrBob - is this because this acts as a polyprotic acid, or because the ratio in the Henderson Hasselbach for HA/A- remains the same?
Tuesday, April 13, 2010 at 10:52pm by HELP

Chemistry
Hydrogen peroxide, H2O2, solution can be purchased in drug stores and used as an antiseptic. A sample of such a solution weighing 1.00 grams was acidified with sulfuric acid and titrated with .02000 M solution of KMnO4. The unbalanced reaction is H2O2(aq) + MnO4-(aq)--> O2(...
Thursday, April 15, 2010 at 5:55am by HELP!!!

chemistry
If the stockroom fails to dry the KHP to remove the waters of hydration, the student's calculated concentration for the standardized base will be (low, high, or unaffected) A drop of NaOH is hanging from the buret tip before the titration of KHP. Once the student begins the ...
Sunday, April 18, 2010 at 2:19am by help

Chemistry
45.0 ml of 9.0x10 the negative 2m hno3 I am needing the steps to help solve the above chem equation
Tuesday, April 20, 2010 at 12:42am by Help

chemistry
If this "point" for a particular titration occurs at pH x, a good indicator for for the titration would be indicator. Note: Provide only 1 indicator name (even if there are other indicators possible) and make sure the spelling is correct. X indicator 0.9
Friday, April 23, 2010 at 7:44pm by help

chemistry
hmmmm this doesn't seem to help
Friday, April 23, 2010 at 7:44pm by help

Chemistry
The vapor pressure of nitrogen at several different temperatures is shown below. Temperature Pressure () 65 130.5 70 289.5 75 570.8 80 1028 85 1718 Use the data to determine the heat of vaporization of nitrogen. Determine the normal boiling point of nitrogen.
Thursday, April 29, 2010 at 12:09am by HELp

chemistry
How many atoms does 2.0 moles of He represent?
Saturday, June 19, 2010 at 6:09pm by HELP!!!

chemistry
Convert 3.01 x 1023 molecules of C2H6 to moles.
Saturday, June 19, 2010 at 6:10pm by HELP!!!

chemistry
How many total atoms are in 1.0 moles of H2O ?
Saturday, June 19, 2010 at 6:11pm by HELP!!!

chemistry
What is the conjugate base of the following substances: a. (CH3)3NH /(CH3)3N b. H3N-CH2-COOH / H3N-CH2-COO c. H3N-CH2-COO / H2N-CH2-COO d. OOC-CH2-COOH / OOC-CH2-COO e. OOC-CH2-COOH / HOOC-CH2-COOH
Sunday, September 19, 2010 at 12:05pm by help

Chemistry
How would you prepare 1L of a .050 M phosphate buffer at pH 7.5 using crystalline K2HPO4 and a solution of 1 M HCl? pka of H2PO4 = 7.2
Sunday, September 19, 2010 at 1:58pm by HELP!!!

Chemistry
I got the first part when I have to find the ratio for base to acid. I didn't know where to go from there. I tried using the C1V1=C2V2 equation but again I am lost.
Sunday, September 19, 2010 at 1:58pm by HELP!!!

Chemistry
Both calcium sulfate and magnesium sulfate can form hydrates with water. Could white anhydrous CaSO4 or MgSO4 be substituted for anhydrous CuSo4? Why or Why not?
Sunday, September 26, 2010 at 8:44pm by HELP!!!

chemistry
A solution was prepared by dissolving 43.0 of in 225 of water. Calculate the mass percent of in the solution.
Friday, October 1, 2010 at 11:25pm by help

chemistry
of KCl
Friday, October 1, 2010 at 11:25pm by help

chemistry
43g
Friday, October 1, 2010 at 11:25pm by help

chemistry
225g
Friday, October 1, 2010 at 11:25pm by help

chemistry
Help please =)
Wednesday, October 13, 2010 at 7:37pm by HELP

chemistry
please
Wednesday, October 13, 2010 at 7:44pm by HELP

chemistry
please
Wednesday, October 13, 2010 at 7:45pm by HELP

Chemistry
calculate the grams of sodium in 17.606 g of Na2CO3
Friday, October 22, 2010 at 3:55pm by HELP

Chemistry
Calculate the number of molecules in 3.1466x10^1 grams of sulfur dioxide, SO2
Friday, October 22, 2010 at 4:01pm by HELP

Chemistry
Calculate the number of molecules in 3.1466x10^1 grams of sulfur dioxide, SO2
Friday, October 22, 2010 at 4:12pm by HELP

Chemistry
Organic hydrogenation reactions, in which H2 and an "unsaturated" organic compound combine, are used in the food, fuel, and polymer industries. In the simplest case, ethene (C2H4) and H2 form ethane (C2H6). If 124 kJ is given off per mole of C2H4 reacting, how much heat is ...
Friday, October 22, 2010 at 9:29pm by HELP !

Chemistry
58970 ? But, it has to be 3 significant figures, right ? So, would it be 5.90e4
Friday, October 22, 2010 at 9:29pm by HELP !

chemistry
How do you know the number of ions present in a compound.
Saturday, October 23, 2010 at 8:14pm by help

chemistry
Its just a general question. I'm trying to get the van't hoff factor and i think you need to know number of ions present. for example how do you know the # ions present in k2s
Saturday, October 23, 2010 at 8:14pm by help

chemistry
To what final volume should you dilute 50.5ml of a 4.75 M KI solution so that 27.5ml of the diluted solution contains 3.10g of KI
Sunday, October 24, 2010 at 3:53pm by help

chemistry
Never mind i figured it out:)
Sunday, October 24, 2010 at 3:53pm by help

chemistry
help
Thursday, October 28, 2010 at 2:48am by help

chemistry
consider the following reactions O+N2->NO+N Ea=315kj/mol Cl+H2->HCl+H Ea=23kj/mol Why is the activation energy for one much lower that the other. The frequency factor is very close in value for the two. Assume they are the same compute the ratio of the reaction constants...
Friday, October 29, 2010 at 12:14am by help

chemistry
In the emission spectrum of hydrogen, some lines are in the infra red range. h l Suggest an electron transition (specify n and n) that is in this range and calculate its corresponding wavelength and delta E.
Monday, November 15, 2010 at 11:33am by help

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