Posts by drbob222

Total # Posts: 55,616

chemistry
I agree but I don't like to use the definition with hydrogen because redox can take plce without hydrogen being involved;. I prefer to use the definition of Oxidation is the loss of electrons. Reduction is the gain of electrons. In O2 ==H2O, O2 has an oxidation state of ...

Chemistry
See your posts above.

Chemistry
See the response by Steve above.

Chemistry
You don't have an equation to use; is this it? CH4 + 2Cl2 ==> CH2Cl2 + 2HCl mols CH4 = grams/molar mass = 1500/16 = approx 100 but you need to do it more accurately. Using the coefficients in the balanced equation, convert mols CH4 to mols of Ch2Cl2. That will be approx...

Chemistry
Have you seen this? http://www.1life63.com/en/omega-in-your-body-oxidation-of-lipids/oxidation-of-lipids

math
Thanks for letting us know. That always helps. Yes, all of us have other things to do but we do this because it's in our blood. I think putting this under math was clever.

Science
Think about it. You are convert electrical energy into light energy. Right?

Science
You must understand that this is a homework HELP site. We help you but we don't do the work. You are wanting answers without doing any of the work.

Sciences
What do you think?

chemistry
No. To start, you don't have enough information to answer because the problem doesn't tell you if the acid is monoprotic, diprotic, triprotic, etc. If you assume it is monoprotic, it is done this way. HA + NaOH ==> NaA + H2O mols NaOH = M x L = 0.268 x 0.0175 = ...

sciences
https://en.wikipedia.org/wiki/Thermal_efficiency#Carnot_efficiency

Chemistry
Here is a good site to read. https://chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Equilibria/Solubilty/Solubility_and_Factors_Affecting_Solubility Agitation affects the RATE of solution but not the final amount that will dissolve. Likewise, the surface area ...

Chemistry 101
It's chlorINE gas is used. Won't it depend upon how much Al is used, also? I assume the author of the problem SHOULD HAVE SAID and excess of Al.Watch the caps; alcl3 doesn't mean anything. For example, Co is cobalt, CO is carbon monoxide, co is company. 2Al + 3Cl2...

PRACTICAL CHEMISTRY
You have too many omissions in the equation. That should e [Cr2O7]^2-, I have no idea what NO-2 is (probably [NO2]^-), [NO3]^- Here is a good site that will tell you to assign oxidation states to each element and use that to balance redox equations. If you have more trouble ...

Chemistry
For one thing, look up the toxicity of Cu compounds.

Science
I agree

Chemistry
If this is a 2+ ion, then the electron configuration for element must be [Kr]4d10 5s2 5p2 Determine what element you're dealing with. Kr has 36e, and you have 14 more which makes 50e total. Element 50 is what? So you write that element symbol down (I'll call it X) and ...

Chemistry
Ca is #20 si tge Ca atom will have 20e. 20Ca = 1s2 2s2 2p6 3s2 3p6 4s2 Remove the last two 4s2 electrons for the 20Ca^2+.

Chemistry
a. Ag^+(aq) + Cl^-(aq) ==> AgCl(s) b. q absorbed by calorimeter = Ccal*dT = 7.31 J/K x 0.770 K = ? c. q absorbed by soln = mcdT = 200 x 4.35 x 0.770 = ? d. dHrxn = b + c e. Calculate mols AgCl formed in the reaction and dH in part d will be heat for that many mols AgCl ...

chemistry
You're posting about 20 or more questions with these 5. We are here to help with the emphasis on help but we expect you to do most of the work. a. The mole fractions are 0.21 for oxygen; 0.78 for nitrogen and 0.01 for argon. Then pO2 = XO2*Ptotal pN2 = XN2*Ptotal pAr =XAr*...

Chemistry
C + O2 ==> CO2 +393 kJ/mol = 393 kJ/12 g C. 1. So 393 kJ x (1,000 g/12 g) = ? = approx 33,000 kJ but that's just an estimate. 2. How much heat is required to melt 1 g ice. That's approx 334 J/g ice but you need to use the value in your text/tables. You have about 33...

Chemistry
If 1 mol O2 occupies 22.4 L at STP then 2 mol O2 will occupy 22.4 x 2 = ? and 3 mols will occupy 22.4 x 3 mol = ? etc.You have 3.45 mol O2. What volume will that occupy. Look at the dimensional work. At STP O2 occupies 22.4L so we know that is 22.4 L/mol. So 22.4 L/mol x # mol...

Chemistry
Yes, 3.65 mols O2. You're half way there. The problem asks for the volume. So 1 mol will occupy 22.4 L at STP. How many L will 3.65 mols occupy?

math if your a genius solve this
I figured 7.05 but of course you can't chop up the students to get 0.05 of one of them so 7 would be correct. And there is a little money left over. See, you were able to do large parts of this.

math if your a genius solve this
You're absolutely right. $7200 is the cost for 7 nights for 5 adults. How much is the cost for 7 nights for 1 student? Then go from there to see how many students could go for the adults' cost.

Chemistry
You're welcome.

Chemistry
You know from your Kc equation that you need concentrations. You have mols and volume; therefore, you know at equilibrium that [SO2] = 0.0550 mol/1.40 dm^3 and [SO3] = 0.0720 mol/1.40 dm^3. Therefore, [SO2] = approx 0.04 M and [SO3] = approx 0.05. You will need to recalculate ...

@ anonymous--CHEMISTRY
Damon is right. You've missed the whole point. The point is that H2O2 in a dark bottle (capped) in a dark room at 3 o C will decompose but very very slowly over time. H2O2 at 37o C poured on a cut (with blood) decomposes much more rapidly because the blood acts as a ...

CHEMISTRY
Blood contains a protein and that acts as a catalyst t speed up the rate of the decomositioin. H2O2 in a bottle aty body temperature contains no catalyst.

Chemistry
You're ok with that symbol. the - sign works a little better than the underline, like this <-> but usually I do <--> or <==> or <->. Yes, it's as easy as adding everything BUT you must be careful what you add. The 50% dissociation means that NH3...

Chemistry!HELP
Is potassium chromate KCrO4. I don't think so.

Chemistry
You need to learn the solubility rules. HgS is the ppt (the solid).

Chemistry
Yes and no. If I put 63/44 into my calculator I get 1.48. As a fraction, 63/44 is exactly what you have. 1 19/44 fraction notation is 1.48 in decimal notation. So you didn't do anything wrong. However, USUALLY, we use decimal notation. Use your calculator to do that. ...

Chemistry
I am a retired university prof. mols = grams/molar mass = ? = 63/44 = ?

Science
I agree

Science
Isn't the answer to this one rather obvious?

Chemistry
I'm confused by the problem. Is that So and Ho for the reaction. If so, then dG = dH - TdS. Products are favored if dG is -.

Chemistry
(V1/T1) = (V2/T2) Don't forget that T must be in kelvin.

AP Chem
See your other post

AP Chem
There are 6.02E23 electrons in 1 mole of electrons, so 550 kJ/mol e x (1 mol e/6.02E23 e) = ? kJ/1 electron. Note the units are kJ/e.

Chemistry
mass = volume x density = 0.05 mL x 1.149 g/mL = ? g O2. n = mols O2 = grams/molar mass = ? Then PV = nRT. Remember T must be in kelvin. V will be in L so convert to mL. Post your work if you get stuck.

CHEMISTRY
I see several problems. You want dHrxn = (n*dHreact) - (n*dHproducts). Using dHo formations is not quite the same as dHbond energies. One problem is the H2O or H-O-H-H. Each OH is 460, you have two of those for 1 mol H2O = 920 and you have 2 mol H2O which is 920*2 - ? The ...

CHEMISTRY
If you had shown your work I could have found the error. You probably used the O-O of 180 instead of the O=O of 498.

AP Biology
I think this is a poorly worded question andthe answers are poor too. Why? If plants are grown for several days in "how much 14CO2" in place of "how much 12CO2" doesn't tell us the conditions initially. The answers are not much better. "A large/...

chemistry
Doesn;t it depend upon how much I2 you have initially.

Chemistry
I didn't look this up but you can Google them and find out.

Chem
I think I know what the author of the problem expects; however, I don't think this is a viable problem BECAUSE you have two unknowns. That is you have x mL KMnO4 as well as y% H2O2 in the 3.4 g sample. That author assumes the x%(which is in grams) and x mL is the same and ...

college chemistry
Doesn't that depend upon the experiment you did to determine the molar mass. How did you do the experiment?

science
I don't see a question here.

Science
Thanks, Ms. Sue. It's been a struggle.

Science
just checking to see if this will post.

Chemistry
eqn 1 + 2*eqn 2 = ? See if doing this doesn't give you the correct equation you want. Ignore eqn 3. You don't need it. A favorite trick when profs want you to think REALLY hard. Eqn 3 is a red herring.

chem
Aniline is a base with that NH2 group and form a salt with the acid HCl. Remember acid + base = salt.

Chemistry
Yes, A is correct.

Chemistry
I didn't do the math.

Chemistry
eqn 3 reversed + 4*eqn 1 + 5*eqn 2 Post your work if you get stuck.

AP Chem
Everything you need tied in a nice bow. http://physics.bu.edu/~redner/211-sp06/class24/class24_heatcap.html

Science
I don't see a question here.

Science
https://www.google.com/search?q=pressure+change+with+height&ie=utf-8&oe=utf-8

Chemistry
https://yeahchemistry.com/questions/re-empirical-formula-fexcoy

chemistry
Kw = 4.57E-15 = (H3O^+)(OH^-) (H2O^+) = (OH^-) (H3O^+) = sqrt(Kw) and convert to pH.

Chem
The digits are right but you are off by a factor of 10. It should be 0.1345 M.

Chemistry
mols = M x L = ? You have L but no M or mols Na2CO3 = grams/molar mass = ? Then mols HCl = mols Na2CO3 x 2 x L. Again, you have L HCl but no mols Na2CO3.

Chem
yes

Chem
72.84 yes 190.5 no but close.

chemistry
The question isn't clear to me. Sorry.

Chemistry
CuS + 2O2 ==> CuO + SO3 (S^2- ==> S^6+ + 8e) (O2 + 4e--> 2O^2-) You want to make the electron gain/loss equal so multiply eqn 1 by 1 and eqn 2 by 2 like this, then add them together. 1*(S^2- ==> S^6+ + 8e) 2*(O2 + 4e-->2O^2-)_ ...

chemistry
See my response abve.

Chem
From the phrasing of the question, I'm not certain of the question; however, the molecular equation to form Fe(ClO4)3 is Fe(OH)3 + 3HClO4 ==> Fe(ClO4)3 + 3H2O but the net ionic equation for that is (3H^+ + 3(OH^-) = 3H2O

Chemistry (12)
PbSO4 is insoluble. The others are OK. I don't know what kind of solubility table you used but I know the solubility rules. Google solubility rules and that will help you know what is soluble and what is insoluble.

@ Rae
I disagree. One person that needs to know is the the cheater; others who MAY cheat also need to know.

CHEMISTRY
4.5% of what strength HNO2? What's Ka of HNO2?

CHEMISTRY
See your duplicate post above. Please use the same screen name.

Chemistry
2 mols C2H6 = 7 mols O2 = 4 mols CO2 etc.

Chemistry
No. v doesn't matter.

Chemistry
If you are determining the number of nodes, and the p orbitals are degenerate, no. However, if the p orbitals are not degenerate then you will have three orbitals but pointed in three directions (along the three axes). YOu can read all about it here. https://en.wikibooks.org/...

Chemistry
(V1/T1) = (V2/T2) Remember T must be in kelvin. ?

chemistry
q = mass H2O x 44.0 kJ/mol = ? Remember to convert the H2O to mols. mols = grams/molar mass = ?

Check my answers Ms. Sue
I disagree with C.

Chemistry
This is a problem to illustrate the common ion effect. The common ion, in this case, is F^- from KF and the presence of KF will decrease the solubility of LfF3 in water. ........LaF3 ==> La^3+ + 3F^- I.......solid.....0.......0 C.......solid.....x.......3x E.......solid...

Chemistry
P*molar mass = density*RT Substitute and solve for molar mass. Remember P = 80.2/760 and T = (273+23)K Then density at STP is molar mass/22.4 = ? g/L.

chem
First we must determine the limiting reagent(LR). mols F2 = approx 70/38 = about 1.84. 2.0 mols CF2Cl2 will produce 2 mols CF4. 1.84 mols F2 will produce 1.84 mols CF4, Therefore, the LR is F2 and CF2Cl2 is in excess. So the rxn releases 401 kJ for 38 g F2. You have 70 g; ...

Science
Read the first paragraph on this page.The key word is nucleus. https://www.google.com/search?q=prokaryotic+vs+eukaryotic&ie=utf-8&oe=utf-8

Chemistry
How many mols do you want? That's mols sucrose = M x L = ? Then mols = grams/molar mass. You know molar mass and mols, solve for grams.

Chemistry
The mass of 1 mole of anything is the same as the molar mass in grams; therefore, mols = grams/molar mass = ?

Gen chem
H2SO4 + 2NaOH ==> 2H2O + Na2SO4 moles NaOH = M x L = ? Using the coefficients in the balanced equation, convert mols NaOH to mols H2SO4. Then M H2SO4 = mols H2SO4/L H2SO4. You know M and mols, solve for L and convert to mL.

Chemistry
I agree citric acid is the LR but I worked it another way. You can compare mols and not go through the grams step.

Chemistry
Yes. This is a standard question in qualitative analysis but it's a little confusing; i.e., I don't know if the idea is to identify the solutions, add an ion which will form a ppt in BOTH, or just what. You need to know the solubility rules. Chloride ion (say NaCl) ...

Chemistry
I didn't get 32 but almost twice that. Post your work and I'll look for the math error.

Chemistry
q = mass H2O x specific heat water x (Tfinal-Tintial) sp.h. stands for specific heat and qcal is calorimeter constant. mass warm H2O x sp.h.H2O x (Tfinal-Tinitial) + mass cool H2O x (Tfinal-Tinitial) + qcal(Tfinal-Tinitial) and solve for qcal. Post your work if you get stuck. _

Chemistry
Some of these look like relatively easy questions to answer so I don't understand what you could be troubling you. If you will explain in detail what you don't understand about each I'll show you what to do.

Science
KE = 1/2*m*v^2

Science
I agree

Chemistry
Remember to ignore that 55.0 g NH4HS since it is a solid and doesn't enter into Kc (or Kp). For every mole of NH4HS that decomposes there will be x mols NH3 and x mols H2S. ......NH4HS --> NH3 + H2S I.......solid....0.....0 C........-x......x.....x E......solid-x...x...

Chem 1C
Can't you use the Arrhenius equation, just plug in the numbers and turn the crank.

Gen chem
H2SO4 + 2NaOH ==> Na2SO4 + 2H2o mols NaOH = M x L = ? Using the coefficients in the balanced equation, convert mols NaOH to mols H2SO4. Then mols H2SO4 = M x L. You know M and mols, solve for L and convert to mL. Post your work if you get stuck.

Chem
To save time I will omit the aq part but you can add that to each cation and anion yourself. I have added (s) to the AgCl to show it is solid. Ag^+ NO3^- + Na^+ + Cl^- ==> Na^+ + NO3^- + AgCl(s) Cancel the ions on each side that are common to both sides to end up with the ...

Chemistry
mols Fe(NH4)2(SO4)2.6H2O = grams/molar mass = ?. Then (A) = mols /L = ? Let's call this Y. (B) = (A) x (5.00/100) = ? (C) = done the same way as (B).

Chemistry
See your other post.

Chemistry
By the way, please don't change screen names. You get faster service using the same name.

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