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April 23, 2014

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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CHemistry
gotta work with moles. How many moles H2SO3 in 36.86g? Since each mole of H2SO3 requires 1 mole of SO2, you need the same number of moles. So, convert back to g of SO2
Wednesday, March 26, 2014 at 12:05pm

CHemistry
SO2(g) + H2O(l)= H2SO(l) What mass of sulfur dioxide is needed to prepare 36.86 g of H2SO3(l)
Wednesday, March 26, 2014 at 11:54am

Chemistry
CIE and NIE for 2 K3PO4 + 3 Fe(NO3)2 = 6 KNO3 + Fe3(PO4)2
Wednesday, March 26, 2014 at 11:50am

chemistry
in an experiment, a 4.000grams sample of aluminum metal is added to a solution containing 5.000grams of dissolved iron chloride. the reaction results in the formation of aluminum chloride and metallic iron. when the reaction is complete, unreacted aluminum remains, and this ...
Wednesday, March 26, 2014 at 11:46am

chemistry
Kf ionic name
Wednesday, March 26, 2014 at 11:22am

Chemistry
Which nucleophile, when reacted with 1-bromopropane (CH3CH2CH2Br), would produce a thiol? OH- SH- I- -OCH3
Wednesday, March 26, 2014 at 11:15am

chemistry
Which nucleophile, when reacted with 1-bromopropane (CH3CH2CH2Br), would produce an ether? I- OH- -OCH3 SH-
Wednesday, March 26, 2014 at 11:14am

Chemistry
So my chem professor had a slide with a question that follows: If you combine 100 ml of 0.10 M HCl and 100 ml of 0.10 M NaOH, and find that the temperature goes up 0.67 degrees K  What is ΔH° for the reac/on: OH(aq)- + H+(aq)->H2O(l)(c H2O= 4.18 J/°C sg, ...
Wednesday, March 26, 2014 at 10:27am

University Chemistry (first year)
Hi I am 10. RP pls. Kimochi
Wednesday, March 26, 2014 at 3:39am

University Chemistry (first year)
Hi I am 10. RP pls.
Wednesday, March 26, 2014 at 3:36am

chemistry
NACL +HNO3 = HCL +NANO3 AGCL + HNO3= NO REACTION With regards from SHABAZ AHMED DAR ( VIVEKANANDA KENDRA VIDYALAYA) BARAGOLAI, ASSAM
Wednesday, March 26, 2014 at 2:39am

chemistry
143.5 g AgCl contains Ag = 108 2.87 g Agcl contains Ag = (108×2.87)/143.5 Answer= 2.16 g Thanks :) with regards from SHABAZ AHMED DAR (VIVEKANANDA KENDRA VIDYALAYA, BARAGOLAI, ASSAM)
Wednesday, March 26, 2014 at 2:26am

chemistry
ah you are right DrBob222. I converted kJ to J.
Wednesday, March 26, 2014 at 2:01am

Chemistry
molecules is not M. I would convert molecules to mol which will be mols/cc and convert that to mols/L which is M.
Wednesday, March 26, 2014 at 1:16am

chemistry
In fact, a rule of thumb in the kinetics business is that reaction rate can be doubled for every 10 degrees T. Since this ratio k2/k1 = about 2.05 I would guess T2 would be close to 365 or something like that.
Wednesday, March 26, 2014 at 12:39am

chemistry
I don't think so. 273 + C = K 273 + C = 17 C = ? not 290?? Second think I notice is that your calculated temperature decreased. k2 is about double k1 so wouldn't you think T would be higher. Did you convert kJ/mol to J/mol? That's a common error.
Wednesday, March 26, 2014 at 12:24am

Chemistry
Okay... I already know that. I plugged in all the numbers and I get 8.2*10^22, which is not the right answer. Can someone show the work for the problem please?
Wednesday, March 26, 2014 at 12:23am

Chemistry
Sorry about that. I got carried away with calculating the mass Ca3(PO4)2. mols ? mols Ca^2+ x (2 mol Na3PO4/3 mol Ca^2+) = ? mols Ca^2+ x 2/3 = ? mols Na3PO4. Does that look familar from above. g Na3PO4 = mols Na3PO4 x molar mass Na3PO4. And that should look familiar from ...
Wednesday, March 26, 2014 at 12:18am

chemistry
IF your equation is correct (and I don't think it is) then 150 ppm is 150 mg/L or 0.150 g/L = (0.150/atomic mass Ca) mols/L = approx 0.00375M. Then M standard soln x mL = ? millimoles. mmols EDTA = twice that M EDTA = mmols/mL. I was under the impression that EDTA ...
Wednesday, March 26, 2014 at 12:11am

chemistry
I got 17 Kelvin in the end. Does that mean my final answer will be 290 C (converted C to K)?
Wednesday, March 26, 2014 at 12:10am

Chemistry
H
Wednesday, March 26, 2014 at 12:09am

Chemistry
@DrBob222: what about the sodium phosphate?
Wednesday, March 26, 2014 at 12:07am

Chemistry
Is this unknown sample Ca^2+. Then 3Ca^2+ + 2PO4^3- --> Ca3(PO4)2(s) You must know mols Ca^2+ from your unknown. Then mols Ca^2+ x (2 mols PO4^3-/3 mols Ca^2+) = mols Ca^2+ x 2/3 = ? mols Ca3(PO4)2. Then g = mols x molar mass.
Tuesday, March 25, 2014 at 11:55pm

Chemistry
Calcium can also be precipitated out of the solution by adding sodium phosphate (Na3PO4) to form solid calcium phosphate. A.) write a net ionic equation for this process B.)calculate the mass of this precipitate you would generate from treating 1.000 L of your unknown sample ...
Tuesday, March 25, 2014 at 11:45pm

chemistry
Based on your titration of the 150ppm standard solution of Ca2+ calculate the molarity of the EDTA solution we used, which is Ca2+ + EDTA4- ----> [CA(EDTA)]2-
Tuesday, March 25, 2014 at 11:41pm

chemistry
Use the Arrhenius equation.
Tuesday, March 25, 2014 at 11:31pm

chemistry
Convert 20m, 12.5m and 3.85m to cm, then pool L x W x depth = volume in cc mass H2O is volume in cc x 1.00 g/cc. Then q = mass H2O x specific heat H2O x (Tfinal-Tinitial). Substitute and solve for q.
Tuesday, March 25, 2014 at 11:29pm

chemistry
The rate constant of a first-order reaction is 4.25 x 10^-4 s^-1 at 350 Celsius. If the activation energy is 103 kJ/mol, calculate the temperature at which its rate constant is 8.75 x 10^-4 s^-1.
Tuesday, March 25, 2014 at 11:21pm

Chemistry
rate = k(CF3CH2F)(OH)
Tuesday, March 25, 2014 at 11:21pm

chemistry
thanks it helped
Tuesday, March 25, 2014 at 11:18pm

chemistry
You can look up the exact numbers but C = about 12 = 36 H = 1 = 5 O = 16 = 32 Then add 36 + 5 + 32 = 73 I don't know where the 292 came from.
Tuesday, March 25, 2014 at 11:14pm

Chemistry
as
Tuesday, March 25, 2014 at 10:58pm

chemistry
please help! how do i find the molecular mass of C3H5O2 molecular mass of 292 g.
Tuesday, March 25, 2014 at 10:46pm

Chemistry
The degradation of CF3CH2F (an HFC) by OH radicals in the troposphere is first order in each reactant and has a rate constant of k=1.6×108M−1s−1 at 4∘C. If the tropospheric concentrations of OH and CF3CH2F are 8.1×105 and 6.3×108 molecules ...
Tuesday, March 25, 2014 at 10:03pm

Chemistry
The concentration of Ca2+ in a particular water supply is 5.7×10−3M. The concentration of bicarbonate ion, HCO−3, in the same water is 1.7×10−3M. What masses of Ca(OH)2 and Na2CO3 must be added to 5.6×107L of this water to reduce the level ...
Tuesday, March 25, 2014 at 10:00pm

chemistry
Question Part Points Submissions Used A swimming pool, 20.0 m ✕ 12.5 m, is filled with water to a depth of 3.85 m. If the initial temperature of the water is 18.9°C, how much heat must be added to the water to raise its temperature to 28.7°C? Assume that the ...
Tuesday, March 25, 2014 at 9:51pm

chemistry
What is your problem with this bekah? For a you must have worked a hundred of weak acids problems with a known starting molarity. At first glance it looks like 2 is a buffer problem that can be solved with the Henderson-Hasselbalch equation.
Tuesday, March 25, 2014 at 9:30pm

chemistry
enzoic acid is a weak monoprotic acid with Ka = 6.5×10-5 M. NaOH(s) was gradually added to 1.00 L of 8.66×10-2 M benzoic acid. 1. Calculate the pH of the solution before the addition of the base. 2. Calculate the pH of the solution after the addition of 5.20×...
Tuesday, March 25, 2014 at 9:14pm

chemistry
I would go with 2 as true. Use pH = pKa + log (acid)/(base) to evaluate the other statements.
Tuesday, March 25, 2014 at 8:56pm

chemistry help
You remember two things. a. Reactions go to completion for one of three reasons. 1. a ppt is formed. For this you need to know the solubility rules. In this case PbS is formed which is a ppt. 2. a gas is formed. For this you need to know what is a gas and what isn't. In ...
Tuesday, March 25, 2014 at 8:46pm

chemistry
With what reaction? 2H2 + O2 ==> 2H2O 5.00 mols O2 x (2 mol H2O/1 mol O2) = 5.00 x 2/1 = 10 mols H2O produced.
Tuesday, March 25, 2014 at 8:31pm

chemistry
I agree with both of you.
Tuesday, March 25, 2014 at 8:27pm

chemistry
how many moles of H2O are produced when 5.00 mols of oxygen gas are used
Tuesday, March 25, 2014 at 8:02pm

chemistry
yes 1 Ba , 2 H , 2 O
Tuesday, March 25, 2014 at 7:49pm

chemistry
Consider a buffer solution consisting of CH3NH3Cl and CH3NH2. Which of the following statements are true concerning this solution? (Ka for CH3NH3+ = 2.3 x 10 -11). 1. A solution consisting of 0.1 M CH3NH3Cl and 0.1 M CH3NH2 would be a more effective buffer than one containing ...
Tuesday, March 25, 2014 at 7:30pm

chemistry
its actually my fault sorry :$ , i wrote the question wrong its barium oxide + water so would it be BaO + H2O --> Ba(OH)2 ??
Tuesday, March 25, 2014 at 7:27pm

Chemistry - Science
Thank you!
Tuesday, March 25, 2014 at 7:20pm

chemistry help
what is lead (II) acetate + hydrogen sulphide --> Pb(C2H3O2)2 + H2S --> how do i figure it out?
Tuesday, March 25, 2014 at 7:13pm

Chemistry - Science (Dr. Bob222)
I've worked this below.
Tuesday, March 25, 2014 at 7:11pm

Chemistry - Science
Ag^+ + Cl^- ==> AgCl mols AgCl = grams/molar mass =? ? mol AgCl = mols Cl^- = mols Ag^+ = mols AgNO3. g AgNO3 = mols AgNO3 x molar mass AgNO3 %AgNO3 = (g AgNO3/mass sample)*100 = ?
Tuesday, March 25, 2014 at 7:10pm

chemistry
No. Barium is Ba. BaO is barium oxide. Ba + H2O ==> Ba(OH)2 + H2. You balance.
Tuesday, March 25, 2014 at 7:04pm

Chemistry
1.58e-4 what? mL? L? Does it sound reasonable that you can dissolve almost 61 g Mg(OH)2 in less than 1 mL (even less than 1 L)? If you had shown your work I could tell instantly what you did wrong. As it is I sit here and type all this out and let you look and see if you can ...
Tuesday, March 25, 2014 at 7:01pm

College Chemistry (DrBob222)
Thank you very much!!! Now it makes sense
Tuesday, March 25, 2014 at 6:54pm

Chemistry
Isn't dG = dGo + RTlnQ?
Tuesday, March 25, 2014 at 6:48pm

College Gen.Chemistry
The straight line of y = 3,256x + 0.007 is the calibration curve of Absorbance on the y axis vs concn on the x axis. So insert 0.545 for y (that's the absorbance) and solve for x (that's the concn). I assume that is concn in grams/250 mL although nowhere is that ...
Tuesday, March 25, 2014 at 6:43pm

Chemistry - Science (Dr. Bob222)
A student wanted to determine the amount of copper in a sample of copper ore. The student dissolved a 2.500 ± 0.001 g piece of copper ore in about 75 mL of nitric acid; then, a complexing agent was added. The student transferred this solution to a volumetric flask and ...
Tuesday, March 25, 2014 at 6:38pm

College Chemistry (DrBob222)
If I didn't mess up somewhere the pKa = 5.20. Interesting problem. mmols NaOH added = 36.12 x 0.1 = 3.612 ...........HA + NaOH ==> NaA + H2O So at the equivalence point you have 3.612 mmols NaA in solution. Now you add 18.06 mL x 0.1M = 1.806 mmols ..........A^- + H...
Tuesday, March 25, 2014 at 6:28pm

chemistry
Google it eg http://www.webqc.org/balance.php?reactio​n=BAO+%2B+H2O+%3D+BA%28OH%292
Tuesday, March 25, 2014 at 6:28pm

Chemistry - Science
A 6.70 g sample of a binary mixture of silver (I) nitrate and sodium nitrate is completely dissolved in water to make a solution. Aqueous barium chloride is then added to this solution in excess to form 3.60 g of silver chloride solid. What is the percent by mass of silver ...
Tuesday, March 25, 2014 at 6:28pm

chemistry
oh so for barium + water the chemical equation is BaO + H2O but how do i figure out the rest?
Tuesday, March 25, 2014 at 6:19pm

chemistry
You are being asked to transform a word equation into a chemical equation. You do this for every problem you work in chemistry. sulfur dioxide + water = sulfurous acid SO2 + H2O ==> H2SO3 SO2 is the anhydride of sulfurous acid.
Tuesday, March 25, 2014 at 6:14pm

chemistry anyone??? help!!
help me please!! i dont get it
Tuesday, March 25, 2014 at 6:08pm

chemistry
what is the chemical & word equation of sulfur dioxide + water i don't understand this, can someone please explain to me how to do this!!?
Tuesday, March 25, 2014 at 5:58pm

College Chemistry (DrBob222)
A solution of an unknown weak acid, HA, is titrated with 0.100 M NaOH solution. The equivalence point is achieved when 36.12 mL of NaOH have been added. After the equivalence point is reached, 18.06 mL of 0.100 M HCl are added to the solution and the pH at that point is found ...
Tuesday, March 25, 2014 at 5:31pm

College Gen.Chemistry
A student wanted to determine the amount of copper in a sample of copper ore. The student dissolved a 2.500 ± 0.001 g piece of copper ore in about 75 mL of nitric acid; then, a complexing agent was added. The student transferred this solution to a volumetric flask and ...
Tuesday, March 25, 2014 at 5:29pm

College Gen. Chemistry - Science
Dear Dr Bob222, Thank you so much! The answer is 35.5 mL on H2O has evaporated.
Tuesday, March 25, 2014 at 5:22pm

Chemistry
The equilibrium constant for the reaction of the weak base aniline is Kb = 4.3e-10. C6H5NH2 (aq) + H2O (l) --> C6H5NH3+ (aq) + OH- (aq). Calculate ΔG at 298 K when [C6H5NH2] = 0.250 M, [C6H5NH3+] = 1.0E-5 M, [OH-] = 0.000480 M i used the equations dG=dG^o - RTlnQ and ...
Tuesday, March 25, 2014 at 5:21pm

Chemistry
What volume in liters will be required to dissolve 60.9 grams of Mg(OH)2? Ksp = 1.8×10-11 After doing the math, i got 1.58e-4, but its not right, so i have no idea what to do now.
Tuesday, March 25, 2014 at 5:07pm

College Chemistry (DrBob222)
See your post below.
Tuesday, March 25, 2014 at 4:56pm

College Gen. Chemistry - Science
So how many mols did you have to start? That's mols = M x L = 0.120 x 0.245 = 0.0294. When some of the water has evaporated you know you still have 0.0294 mols there. And the molarity now is 0.348M and not 0.245M. So M = mols/L. M = 0.348; mols = 0.0294. Solve for L of ...
Tuesday, March 25, 2014 at 4:55pm

College Chemistry (DrBob222)
You have 120.0 mL of a 0.245 M solution of NaCl in an open beaker. After several days, you test the solution and find that it now has a concentration of 0.348 M. How much water must have evaporated from the beaker given the new concentration?
Tuesday, March 25, 2014 at 4:52pm

College Gen. Chemistry - Science
You have 120.0 mL of a 0.245 M solution of NaCl in an open beaker. After several days, you test the solution and find that it now has a concentration of 0.348 M. How much water must have evaporated from the beaker given the new concentration?
Tuesday, March 25, 2014 at 4:47pm

Chemistry
a) mols = grams/molar mass b) q = mass H2O x specific heat H2O x delta T That gives you delta H/10.1 and delta H/mol = delta H/10.1 g x ( molar mass/1 mol) and convert that to kJ/mol
Tuesday, March 25, 2014 at 4:29pm

chemistry
You can't without knowing how much of the oxalate you have; however, you may find the ratio of oxalate to permanganate from the below. 2MnO4^- + 5C2O4^2- + H^+ ==> 10CO2 + 2Mn^2+ The above equation isn't completely balanced but you may complete it if you wish; ...
Tuesday, March 25, 2014 at 3:53pm

chemistry
Ag^+ + Cl^- ==> AgCl mols NaCl = 0.05g/molar mass = ? mols AgNO3 = mols NaCl M AgNO3 = mols AgNO3/L AgNO3 You know M and mols, solve for L AgNO3 and convert to mL.
Tuesday, March 25, 2014 at 3:45pm

chemistry
How ml silver nitrate solution (0.05 mol / l) K = 1.0000 consumed for titration of sodium chloride, 0.0500 g. MW Sodium chloride 58.44.
Tuesday, March 25, 2014 at 2:37pm

Chemistry
g unit
Tuesday, March 25, 2014 at 2:30pm

Chemistry
g
Tuesday, March 25, 2014 at 2:30pm

chemistry
How do I determine how many moles of KMnO4 it takes to neutralize C2O4-?
Tuesday, March 25, 2014 at 2:17pm

Chemistry: Check my answers?
12 : is false everything else looks great
Tuesday, March 25, 2014 at 1:23pm

chemistry
delta T = Kf*m Substitute and solve for m = molality m = mols/kg solvent Substitute and solve for mols. mols = grams/molar mass. You know grams and mols, solve for molar mass.
Tuesday, March 25, 2014 at 12:53pm

Chemistry
5g/100 = (K2CrO4) mols K2CrO4 = grams/molar mass = approx 0.026 but you should do it more accurately. K2CrO4 --> 2K^+ + CrO4^2- So (K2CrO4) = 0.026 mol/0.1L = 0.26 M (K^+) = 2*0.26 = ?M (CrO4^2-) = 0.26M
Tuesday, March 25, 2014 at 12:51pm

Chemistry
a. 3.67 mg/mL = 3.67 g/L 3.67 x (1 mol/461.01) = 7.96E-3 = (PbI2) ..........PbI2 --> Pb^2+ + 2I^- I.........solid....0........0 C.........solid....x........2x E.........solid....x........x Ksp PbI2 = (Pb^2+)(I^-)^2 Ksp = (7.96E-3)(2*7.96E-3)^2 = ? NOTE: (I^-) = twice (Pb^2...
Tuesday, March 25, 2014 at 12:46pm

Chemistry
...........Al(OH)3 ==> Al^3+ + 3OH^- I.........solid.........0.......0 C.........solid.........x.......3x E.........solid.........x.......3x Substitute the E line into the Ksp expression for Al(OH)3 and solve for x = (Al^3+). Convert that to OH^-, change to H^+ and convert ...
Tuesday, March 25, 2014 at 12:18pm

Chemistry 2
...........Ag2CrO4 ==> 2Ag^+ + CrO4^2- I..........solid......0.......0 C..........solid......2x.......x E..........solid......2x.......x Substitute the E line into the Ksp expression and solve for x
Tuesday, March 25, 2014 at 12:07pm

Chemistry
See your post on Ag2CrO4.Worked the same way with solubility in M. Convert that to grams.
Tuesday, March 25, 2014 at 12:04pm

Chemistry 2
...CuBr(s) + 4NH3 ==> Cu(NH3)4^2+ + Br^- I....solid....0.69.....0............0 C....solid.....-4x.....x............x E....solic....0.69-x...x............x What we usually do is to say that this reaction goes essentially to completion since Kf for the complex is such a large...
Tuesday, March 25, 2014 at 12:01pm

Chemistry
10.1g of potassium nitrate were dissolved in 50cm^3 of water. the temperature fell by 16 degrees celsius. Determine (a) the number of moles of potassium nitrate dissolve in 50cm^3 of water. (b) heat change that would be produced if one mole of potassium Nitrate dissolve ...
Tuesday, March 25, 2014 at 11:51am

Chemistry
well, since 1 atm = 760 mm Hg, what do you think? Be careful with the units.
Tuesday, March 25, 2014 at 11:44am

incomplete--Chemistry

Tuesday, March 25, 2014 at 11:35am

Chemistry
What can be said about the presence of each of these groups of cations in the orginial solution
Tuesday, March 25, 2014 at 10:48am

Chemistry 2
CALCULATE THE SOLUBILITY OF CuBr in 0.69 M NH3
Tuesday, March 25, 2014 at 10:24am

Chemistry 2
What is the solubility of silver chromate in pure water
Tuesday, March 25, 2014 at 10:10am

Chemistry
The Ksp of manganese (II) hydroxide, Mn(OH)2 is 2.00x10^-13. Calculate the solubility of this compound in g/L?
Tuesday, March 25, 2014 at 9:59am

chemistry
2C4H10 (g) + 13O2 (g) → 8CO2 (g) + 10H2O (g)
Tuesday, March 25, 2014 at 8:31am

Chemistry
. A student performed a recrystallization of phthalic acid and used 35 mL of water as solvent. Assuming no loss of solvent to evaporation, calculate the loss of product in the filtrate based on the solubility of phthalic acid
Tuesday, March 25, 2014 at 6:58am

Chemistry
if the pressure read by the barometer is 0.882atm, what is the height of the column of mercury in cm?
Tuesday, March 25, 2014 at 3:26am

Chemistry
I don't really understand how to do this problem, or where to start exactly. Can someone explain to me where to start and how I can solve the problem in a step by step process? Thank you in advance! 1. An acetic acid / sodium acetate buffer solution is also 0.020 M AlCl3. ...
Tuesday, March 25, 2014 at 12:37am

Chemistry
Can someone show and explain to me step by step how to do the problems? I feel like I am doing it incorrectly. a) The solubility of PbI2 is 3.67 mg per mL. What is the Ksp? b) Three drops of 0.20 M potassium iodide are added to 100.0 mL of 0.010 M lead nitrate. Will a ...
Tuesday, March 25, 2014 at 12:33am

Chemistry
Mohr's indicator is 5g/100ml of K2CrO4 in water. What is the concentration of CrO4^2- in the indicator? (in mol/L)
Tuesday, March 25, 2014 at 12:20am

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