Saturday
October 25, 2014

Posts by DrBob222


Total # Posts: 44,728

Chemistry
Is this part of the same question? If so you must have some of A, some of B and some of C Mix A with the three. It will not react with A^- but will with B^- and C^- Mix B with the three. It will not react with A or B or C. Mix C with the three and it will not react with A but ...
October 7, 2014

chemistry
density = mass/volume mass = 17.62 g. volume = 36.1 mL - 29.9 mL = ? Substitute and solve for density.
October 7, 2014

chemistry 112
mols H2SO4 = M x L = ? Using the coefficients in the balanced equation, convert mols H2SO4 to mols NaOH. Then M NaOH = mols NaOH/L NaOH
October 7, 2014

Chemistry
I found this and it has A,B,and C in it but the two questions don't seem to be the same nor do they have any obvious connection. http://www.jiskha.com/display.cgi?id=1412727782
October 7, 2014

Chemistry
You must have more information than that but I can't find the other post.
October 7, 2014

Chemistry
5O2 + 2N2 ==> 2N2O5 mols O2 = grams/molar mass = ? Using the coefficients in the balanced equation, convert mols O2 to mols N2O5 Now convert mols N2O5 to grams with g = mols x molar mass = ?
October 7, 2014

chemistry
mols = g/molar mass. You know molar mass and mols, solve for grams.
October 7, 2014

Chemistry
NaOH + KHP ==> NaKP + H2O Note that 1 mol NaOH = 1 mol KPH. mols KHP = grams/molar mass mols NaOH = mols KHP. M NaOH = mols NaOH/L NaOH. You now mols and L, solve for M
October 7, 2014

Chemistry
Calculate mols H^+ from the acids and mols OH^- from the bases. Total H^+ and total OH^- and you'll know which is the larger. Subtract one from the other to see which is in excess and by how much.
October 7, 2014

Chemistry
C + B^- ==> C^- + B You know B^- us colorless and it turns yellow which is the color of B. So the reaction is as I wrote above. C gains electrons in going to C^- so it is reduced. B^- loses electrons in going to B. It is oxidized. C+ A^- ==> stays red which means no ...
October 7, 2014

CHEMISTRY
Wouldn't you think less than?
October 7, 2014

chemistery
2NaOH + H2SO4 ==> 2H2O + Na2SO4 mols NaOH = grams/molar mass = 0.644/40 = approx 0.016 but you need a better answer than this estimate. mols H2SO4 = 1/2 mols NaOH (Look at the coefficients in the equation)= 0.008. M H2SO4 = mols/L. You know mols and you know L, solve for M...
October 7, 2014

Chemistry
A chemical change occurred. A gas was released and not all of the compound decomposed. It was a compound since a gas was evolved and that wasn't all of the material.
October 7, 2014

College chem
mols P = 0.142/31 = 0.0046 approx mols F = 0.436/19 = 0.023 Now find the radio of these to each other with the smallest being no less than 1.00. The easy way to do that is divide the smallest number by itself then divide the other number by the same small numer.
October 7, 2014

Chemistry
(V1/T1) = (V2/T2)
October 7, 2014

chemistry
mols = M x L = ? Then g = mols x molar mass
October 7, 2014

Chem
2KOH + H2SO4 ==> 2H2O + K2SO4 mols KOH = M x L = 0.0217 mols H2SO4 = 0.01085 mols KOH needed = 2*0.01085 = 0.02170g so the solutions exactly neutralize each other. mols H2O formed = 0.02170 volume = 21.70 + 21.70 = 43.40 mL g H2O = 43.40 grams qrxn = mass H2O x specific ...
October 7, 2014

Chemistry
I do these this way. You start with 5.00M and you dilute 20 mL to 250. You know the solution will be more dilute; therefore, 5.00 x (20/250) = 0.400 M Another way is to say what is the dilution; it is 20/250 = 1 in 0.08 so the final concn must be 5.00 x 0.08 = 0.400. Finally, ...
October 7, 2014

Chemistry
Zn + I2 ==> ZnI2 mols Zn = grams/atomic mass = ? mols I2 = grams/molar mass = ? convert mols Zn to mols of the product using the coefficients in the balanced equation. Do the same for converting mols I2 to mols of the product. It is likely that these two values will not ...
October 7, 2014

Chemistry
You can do this two ways. The first is to take equation 1 and use dHrxn = (n*dHf products) - (n*dHf reactants). When you look these up you will find dH Fe is zero and dH O2 is zero so it is a simple calculation and you don't have anything else to do. OR you can recognize ...
October 7, 2014

CHEMISTRY 56
(P1/T1) = (P2/T2)
October 7, 2014

CHEMISTRY
I don't understand the question.
October 7, 2014

CHEMISTRY
waves
October 7, 2014

chemistry
Let me write you a process to follow. Copy this. It will work almost all of your stoichiometry problems. 1. Write and balance the equation. C + O2 ==> CO2 2. Convert what you have into mols. mols = grams/atomic mass 7.10/12 = about 0.6 but you need a better answer than that...
October 6, 2014

Chemistry
mols HCl = M NaOH x L NaOH - ? mols KCl+HCl = M AgNO3 x L AgNO3 = ? mols KCl = (mols KCl+HCl)-mols HCl(from NaOH data) g HCl = mols HCl x molar mass HCl = ?g HCl in the 25 cc. g KCl = mols KCl x molar mass KCl = ?g KCl in th 25 cc. Convert g in 25 cc to g/dm^3
October 6, 2014

Chemistry
The easiest way to do this is to use the dilution formula of c1v1 = c2v2 1.5v = 0.38*500
October 6, 2014

chem
(1/2^3)*initial = 33.1 mg Solve for initial
October 6, 2014

chem
(amu x fraction) + (amu x fraction) + (amu x fraction) + amu x fraction) + (amu x fraction). Substitute each isotope and fraction abundance; e.g. (45.953*0.08) + (46.952*0.0730) etc etc etc = atomic mass.
October 6, 2014

chemistry
See your last post.
October 6, 2014

chemistry
Mg = 20.07 MgO = 20.07+6.70 = total %Mg = (20.07/total)*100 = ?
October 6, 2014

chemistry
This is a limiting reagent (LR) problem but they tell you that you have some S left over which means the LR is Cu. 2Cu + S ==> Cu2S Follow the HgO problem to find mols Cu used up (all of it) and mols Cu2S formed (Note: the 9 g S unused is not use OTHER than so that you know...
October 6, 2014

chemistry
2HgO ==> 2Hg + O2 mols HgO = grams/molar mass = ? Using the coefficients in the balanced equation, convert mols HgO to mols O2 Then convert mols O2 to g. grams = mols x molar mass. This is the theoretical yield (TY). The actual yield (AY) is 1.8g %yield = (AY/TY)*100 = ?
October 6, 2014

Chemistry
I agree with all of your answers.
October 6, 2014

chemistry
mol = grams/molar mass = ?
October 6, 2014

Chemistry
To answer Lu the answer is zero. There is no Cr2S3 in the above problem. A. The easiest way is to calculate the minimum amount of H2O for BOTH solutes. At 50C, solubility KNO3 is 80/100. We want to dissolve 13.8g KNO3. How much H2O do we need That is 100 g x 13.8/80 = about ...
October 6, 2014

CHEMISTRY 45
highest rate is lowest molar mass lowest rate is highest molar mass
October 6, 2014

CHEMISTRY 44
Close. I punched in the numbers like this and obtained 1.65 mL x (364.45/273.65) = 2.1975 which I would round to 2.20 mL and not 2.19.
October 6, 2014

Chem
Pa and the ones above are ok. For kPa I would have used 101.325/1 atm and rounded at the end.
October 6, 2014

CHEMISTRY 3
What's the problem? It looks just like the one you had earlier. Use the coefficients. They will convert whatever you have into whatever you want.
October 6, 2014

CHEMISTRY 2
Some parts right; some wrong. I didn't get the same answer you did when multiplying M x L = ? For mols K2SO4 I obtained 0.00571 and for Pb(ac)2 I obtained 0.00396. That doesn't change the identification of the limiting reagent but it points up a problem on using your ...
October 6, 2014

chemistry
mols C in 52.0g C is mols = grams/atomic mass = 52/12 = ? Then there are 6.022E23 atoms in 1 mol of any kind.
October 6, 2014

chemistry
mols C in 52.0g C is mols = grams/atomic mass = 52/12 = ? Then there are 6.022E23 atoms in 1 mols of atoms.
October 6, 2014

Chemistry
The H atoms on HCtriplebondCH are acidic. That is true. It is true also that the H atoms on H2C=CH2 are acid but they are weaker than on acetylene so that part you heard is true also. If you go one step further and look at H3CCH3 those H bonds are not acid enough to even ...
October 6, 2014

Chemistry
C'mon. add it up.
October 6, 2014

Chem AS
Poor question. NaCl is the only one of those listed that would not be, at least slightly, acidic. AlCl3, BaCl2, CuCl2 and FeCl2 all would be at least slightly acidic. AlCl3 would be the most acidic because it's a more active metal than the others. Why are they acidic? ...
October 6, 2014

Chemistry
38.0 mi/gal x (1 km/0.6214 mi) x (1 gal/3.78L) = ?km/L Then ? km/L x #L = 142 km Solve for #L. Check that to make sure te units cancel.
October 5, 2014

CHEMISTRY
Basically it increases the molar mass; i.e., if you have H2O vapor the molar mass is 18 but if you have a dimer (H2O)2 or trimer (H2O)3 the molar mass would be 36 or 54. In practice you get some kind of an average because these link ups are quasi-stable.
October 5, 2014

CHEMISTRY
Ptotal = Pgas + pH2O Pgas = ?
October 5, 2014

chemistry
I would think Fe2S3 would form with H2S and CaS is soluble. You might have to play around with the pH before addition of H2S to avoid the reduction of S^2- to free S which usually is in the form of colloidal S.
October 5, 2014

chemistry
And your question is? How much heat is transferred to the ring? q = mass ring x specific heat Au x (Tfinal-Tinitial)
October 5, 2014

Chemistry
2NaOH + H2Ox ==> Na2Ox + 2H2O mols NaOH = M x L = 0.1 x 0.1 = 0.01 mols H2Ox = 0.01 x (2 mols NaOH/1 mol H2Ox) = 0.01 x 2 = 0.02 mols NaOH Then M H2Ox = mols H2Ox/L H2Ox. You know M and you know mols, solve for L. Convert to mL if desired.
October 5, 2014

Chemistry
delta T = Kb*molality You know delta T (0.500C) and Kb, solve for m. m = mols solute/kg solvent. You know m and kg solvent, solve for mols Then mols solute = grams/molar mass. You know mols and molar mass, solve for grams.
October 5, 2014

Chemistry
Let X = fraction Cu63 and 1-X = fraction Cu65 --------------------- X*63 + (1-X)*65 = 63.55 Solve for X and 1-X and convert each from fraction to percent.
October 5, 2014

Chemistry
See your post above.
October 5, 2014

Chem 1330
1s2 2s2 2p6 3s2 3p6 4s1 So n = 4 l = 0 because it's an s electron ml = 0 because l = 0 ms = 1/2
October 5, 2014

Chem HELP!!
3p so n = 3 l = 1 because it's a p ml can be -1 or 0 or +1 You take it from here. You can immediately rule out a because of mL, b because of n, c because l, etc.
October 5, 2014

Chemistry
And what was your problem with my response to your first post?
October 5, 2014

chemistry
1.06 g CaCO3 x (atomic mass Ca/molar mass CaCO3) = ? g Ca %Ca = (g Ca/mass pill)*100 = ?
October 5, 2014

Chemistry
Both of your conjectures are correct but the second one doesn't answer the question. Your first educated guess is correct; the MAX temperature of the evaporating dish MUST be 100 C because that's the boiling point of water. The evaporating dish CAN'T get hotter ...
October 5, 2014

chemistry
Zn + 2HCl ==> H2 + ZnCl2 mols Zn = grams/molar mass Using the coefficients in the balanced equation, convert mols Zn to mols ZnCl2. Now convert mols ZnCl2 to grams. g = mols x molar mass.
October 5, 2014

Chemistry Help! (Rydberg Equation)
1/wavelength = R(1/n^2 - 1/n^2) where the two n symbols are n1 for the first one and n2 for the second. So the shortest wavelength (the most energy) will come when an electron falls from the outside most energy level to the inner most energy level. Therefore, plug in n1 = 1 ...
October 5, 2014

CHEM, HELP!!
1. E = hc/wavelength. Solve for wavelength in meters and convert to nm. 2. By the orbit/shell/energy level (take your pick) in which it is located.
October 5, 2014

Chemistry
The easiest way to do 2 is to calculate the energy of each wavelength listed. For #2, wavelength = h/mv Of course you must convert 24.0 mi/h to m/s. The easy way to do that is to type in google "24.9 miles/hour to m/s" without the parentheses and hit the enter key.
October 5, 2014

chem
The equation is balanced. mols Cl2 = 360/70.9 = ? mols AlCl3 = ?mols Cl2 x (2/3) = ? I think the 1/53.96, whatever that is, is the problem.
October 5, 2014

chem
What's the 1/53.96 term?
October 5, 2014

science
http://hyperphysics.phy-astr.gsu.edu/hbase/biology/mitochondria.html
October 5, 2014

science
http://www.bio.umass.edu/biology/conn.river/calvin.html
October 5, 2014

CHEMISTRY
You do all of these with the factors to convert from any material to any other material. For example, to convert 4 mol N2H4 to mols N2O4 needed it is 4 mols N2H4 x (1 mol N2O4/2 mols N2H4) = 4*1/2 = ? 4 mols N2H4 to mols H2O produced is 4 mols N2H4 x (4 mol H2O/2 mols N2H4) = ...
October 5, 2014

Basic Chemical Engineering
Take a look at this. I don't know much about dyeing but this looks like flow diagrams.
October 5, 2014

Basic Chemical Engineering
Here are several but I didn't look at any of them. Take your pick. https://www.google.com/search?q=textile+dyeing&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=sb
October 5, 2014

chem
The long way: 14 mols A and 14 mols B will produce 14*0.50 = 7 mols C. Then C will produce 7*0.9 = 6.3 mols D. The short way: overall yield is 0.5*0.9 = 0.45 or 45%. 14*0.45 = 6.3
October 5, 2014

Chem Help Please!
What about placing a relatively large amount of F in the same flask? That way the reverse F+D ==> C + D reaction is enabled and by Le Chatelier's Principal the decomposition of C should be minimized.
October 5, 2014

Chem Urgent Help Please!!!!
The answer to #1 depends upon how you define large scale. Chromatography has been used for prep purposes; as far as I know mg to g quantities can be prepared this way. #2. In theory you could dissolve the material in some solvent and subject both to chromatography. See if the ...
October 5, 2014

Chemistry
What in the world is 22.6 til-%? and 8.6 til=%
October 5, 2014

chemistry
What reaction? The most plausible answer for a question that leaves me with questions is dH rxn = -36.1 kJ since it is exothermic.
October 5, 2014

chemistry
basic solution. Pb + 2OH^- ==> Pb(OH)2 + 2e O2 + 4e + 2H2O ==> 2OH^- + 2OH^- Multiply equation 1 by 2 and equation 2 by 1 and add. Cancel any ions/molecules common to both sides.
October 5, 2014

Chemistry
6.42E22 atoms (I guess) x (1 dozen/12)= a huge number.
October 4, 2014

Chemistry
4.25% NaOH by mass means 4.25 g NaOH/100 g solution. In 2000 g of the solution we will have 4.25 x (2000/100) =
October 4, 2014

chem
Work it out. mols Cl2 = grams/molar mass = ? mols = ?mols Cl2 x (2 mols AlCl3/3 mols Cl2) = ? mols Cl2 x 2/3 = ? g AlCl3 = mols AlCl3 x molar mass AlCl3. my opinion? I think so.
October 4, 2014

chem
See your other post.
October 4, 2014

chemistry
OH is one.
October 4, 2014

Chemistry
Didn't I answer this earlier? You have 0.2M KI and it has been diluted. So the initial concn is 0.2 x [(25 mL/(25 + 48+1+1+25)] You have 0.4M Na2S2O3 so the initial concn is (before any reaction) is 0.4 x (1 mL/total ML)
October 4, 2014

chem
How many mols is 1 g NaCl? That's mols = grams/molar mass Then 1 mol contains 6.02E23 molecules.
October 4, 2014

chem
All of the stoichiometry problem are worked alike. 1. Write and balanced equation which you have. 2. Convert 30 g H2O to mols. mol = grams/molar mass 3. Using the coefficients in the balanced equation, convert mols H2O to mols or the product. 4. Now convert mols product to ...
October 4, 2014

chemistry
AgCl is very sparingly soluble in water; NaNO3 is soluble in water. Look in your text/notes for properties of solids, liquids, and gases.
October 4, 2014

chemistry
See your post above.
October 4, 2014

Chemistry
https://www.google.com/search?q=lewis+structure+CCl4&client=firefox-a&hs=fWq&rls=org.mozilla:en-US:official&channel=sb&tbm=isch&imgil=Zw725nL4iuBo8M%253A%253Bbx1IGbF8BPqTgM%253Bhttp%25253A%25252F%25252Fwww.tutor-homework.com%25252FChemistry_Help%25252FMolecular_Geometry%...
October 4, 2014

chemistry
This is a limiting reagent (LR) problem. Determine the limiting reagent. Use the coefficients in the balanced equation to convert mols of the LR to mols of the product. Then convert mols of the product to grams by = mols x molar mass.
October 4, 2014

chemistry
mols CO2 = 1.5 L x (1 mol/22.4 L) = ? Then mols O is twice that. 1 mol of anything contains 6.0E23 of that anything.
October 4, 2014

chemistry
4X + 3O2 ==> 2X2O3 mols O2 = 7.2/32 = about 0.225 mols X = 0.225 x 4/3 = about o.9 mols X = grams/molar mass. You know g and mols, solve for molar mass
October 4, 2014

chem.1
(P1V1/T1) = (P2V2/T2) Don't forget T must be in kelvin.
October 4, 2014

Chemistry
mols KI = mols I^- = M x L = ? Then (I^-) = mols/L of solution. Total L = 25 + 48 + 1 + 1 + 25
October 4, 2014

chemistry
2C2H6 + 7O2 ==> 4CO2 + 6H2O b. dHrxn = (n*dHf products) - (n*dHf reactants) c. q = dHrxn from b x (265g/2*molar mass C2H6) d.e.f. Follow a,b,c steps. Post your work if you get stuck.
October 3, 2014

chemistry
mols Br^- from HBr = M x L = ? mols Br^- from FeBr2 = M x L x 2 = ? M Br^- in solution = (total mols/total L)
October 3, 2014

chemistry
You do the math and s.f. This is a limiting reagent (LR) problem. You know that because amounts are given for BOTH of the reactants. 1.Write and balance the equation. CH4 + 2O2 ==> CO2 + 2H2O 2a. mols CH4 = grams/molar mass = ? 2b. mols O2 = grams/molar mass = ? 3a. Using ...
October 3, 2014

chemistry
mols Hg = 4.2E21/6.02E23 = ? grams Hg = mols x atomic mass = ? Since mass = volume x density that can be rearranged to volume = mass/density. Substitute mass from above and density in the problem and solve for mL as the volume and convert to L.
October 3, 2014

chemistry
You probably meant AgNO3 and (NH4)2 SO4 Ag^+ silver ion is right. NO3^- is nitrate ion. NH4^+ is the ammonium ion SO4^2- is the sulfate ion. Ag2SO4 may b formed if you have aqueous solutions that are mixed. Ag2SO4 is limited solubility so it may or may not precipitate. It all ...
October 3, 2014

chemistry
You might determine the density. You might try solubility in certain solvents. I will leave you to write how that could be done.
October 3, 2014

chemistry
This is a limiting reagent (LR) problem. 1. Write and balance the equation. You have that. 2a. mols TiO2 = grams/molar mass = ? 2b. mols Cl2 = grams/molar mass = ? 3a. Using the coefficients in the balanced equation, convert mols TiO2 to mols of the product. 3b. Do the same ...
October 3, 2014

Chemistry
See your post above.
October 3, 2014

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