Posts by DrBob222

Total # Posts: 55,182

chemistry
CH4 + 2O2 ==> CO2 + 2H2O Here is the balanced equation. Use it to answer the question.

Chemistry
mols CuSO4*5H2O = grams/molar mass M CuSO4*5H2O = mols/L = ? You have 1 mol CuSO4 in 1 mol CuSO485H2O; M CuSO4 = mols CuSO4/L solution.

Chemistry
p1v1/t1 = p2v2/t2

Chemistry
See your next post. Same formula.

science
Two substances make one substance. That's synthesis. Also this is an oxidation-reduction (redox) reaction.

chemistry
q = mass H2O x specific heat H2O x delta T.

Chemistry-Balancing equations
http://www.chemistry.wustl.edu/~edudev/LabTutorials/AirQuality/Ozone.htm

chemistry
What are you using for Ksp AgBr? What are you using for Ksp Ag2CrO4? What are your possible answers?

Chemestry
FeCl2*3H2O, you take it from there.

Chemistry
So 205.9 kJ is needed to produce 3; 205.9/3 kJ will be needed to produce 1 mol and since that rxn is only 80.5% efficient then 205.9/3/0.805 will be needed to produce 1 mol at that level of efficiency. Do the same for the H2O electrolysis and compare.

chemestry
I prefer to do it this way. Na2SO4 + 2HCl ==> 2NaCl + H2SO4 Then H2SO4 decomposes by H2SO4 ==> H2O + SO3 Then SO3 decomposes by 2SO3 --> 2SO2 + O2 You can put all of this together as 2Na2SO4 + 4HCl ==> 4NaCl + 2H2O + 2SO2 + O2

Just Curious
To add to Writeacher, many of the retired tutors on this website have more than 50 years experience teaching their "favorite" subject.

Physical Chemistry
We can't draw diagrams/structures on this forum and most of the answers to your questions can't be done easily on this site. If you can rephrase or reconstruct them perhaps we can help.

Physical Chemistry
15. Just like the H formula, just add Z^2 to it 16. # electrons is 2 times the number of subshells; i.e., 1s so 2 electrons, 3p to 6 electrons, 5d so 10 electrons, etc.

chemistry
I would rather see the atomic weight of each isotope; failing that I'm assuming they are 71 and 74. 0.80(71) + 0.20(74) = ?

Science
What's E.f

chemistry
What's ORS?

Anal chem
HC2H3O2 = HAc Let Y = (HAc) needed to make pH = 4.0 or (H^+) of 1E-4 M. .......HAc ==> H^+ + Ac^- I......Y.......0.....0 C.....-x.......x.....x E.....Y-x......x.....x Ka = (H^+)(Ac^-)/(HAc) Ka = (x)(x)/(Y-x) You know Ka (or you can look it up), you know x, solve for Y. I ...

Chemistry
No. Ethanoic acid (acetic acid is miscible---soluble in all proportions--- in water).

electronic
We can't draw structures/diagrams on this forum. I suggest you Google this to determine the differences/similarities between Cu/Si/Ge.

Chemistry
mols Na2CO3 = grams/molar mass = ? 1 mol will contain 6.022E23 molecules.

Chemistry
What's the meaning of ff?

oops--typo--chemistry
Na3CO3 should be Na2CO3. Those pesky numbers move when we least expect it. :-)

Chemistry
I can't help with this as my knowledge of using acetic acid as a solvent is limited.

Chemistry
I don't think so. Concentrated solutions act as buffers but not neutral solutions. Think about how much the pH changes when ONE DROP of 0.1 M HCl or 0.1M NaOH is added to a neutral solution. In fact, you can calculate how much the pH changes. Remember how those titration ...

Chemistry
I think you misunderstood the site where you obtained that information. A catalyst does speed up the reaction and only minimum amounts are needed. Increasing the catalyst increases the rate UP TO A POINT. When you say increasing the amount of catalyst STOPS if we add excess ...

Chemistry
Frankly, I think that is being a little picky. If 2 doesn't explain 1, then you and I MUST ALREADY KNOW that we intend to assign F a negative 1. If we don't already know that then 2 tells us that we should be assigning F a -1. I would be inclined to argue with the key ...

Chemistry
Aren't both right? F goes from zero on the left to -1 on the right which is a gain of electrons. A gain of electrons is reduction which makes it the oxidizing agent. I assume "oxidizer" means oxidizing agent. Since F2 has the highest electronegativity of any ...

Chemistry
I'm still confused, somewhat, but my gut feeling is you can not make any general statements about it. I think you can find some cases in which that is true and some in which it isn't true. At the moment, however, I can't come up with examples of either so I'm ...

Chemistry
I don't understand the question. At what temperature is one a liquid and the other a gas? Is it the gas going to a solid or the liquid going to the solid.

Chemistry
7.50 what? percent? Is that 7.50% by mass NH3 solution. Also, is that a density of 0.973 g/mL; surely not 0.970 g/mol. If so, per mols of what?

CHEMISTRY
equivalent weight AlCl3 = molar mass AlCl3/3 equivalents AlCl3 = grams/equivalent weight N = equivalents/L solution

Chemistry
Not really. Chloride iond don't hydrolyze because they are such weak bases compared to H2O. Hydrolysis is controlled with the strength of the ion as an acid or base compared to H2O. When the atom is attached to a molecule, such as benzene or something like that (...

Chemistry
Cl^-(ions) don't hydrolyze because H2O is a strong base. NH4^+ hydrolyze (to NH3 and H3O^+) because they are a stronger acid than H2O. Remember NH4Cl is an ionic bond. In cloroethanoic acid the bond is more covalent.

Algebra
No, that isn't right.

Chemistry
[V4O12]^4- Remember the V and O must add to -4. 4*V + 12*-2 = -4 4V - 24 = -4 4V = +20 V = ?

Chemistry
mols K2SO4 = grams/molar mass = ? mols [SO4]^2- = mols K2SO4 since there is 1 mols SO4 in 1 mol K2SO4. L = 100 mL = 0.100 L Then M = mols/L

Science
google vitamin C

Chemistry-@DrBob222
I agree withe the answer key AND I agree with your reasoning for the answer in the answer key.

Can't submit follow up questions or thank the tutor
I don't think so. Your newest post is OK.

Chemistry
This is an exercise in Le Chatelier's Principle. That principle says that a system in equilibrium will shift (that is it will move to the left or to the right) when we do something to it. The shift will be such that it will try to undo what we did to it. I'll do the ...

Science
What kind of solutions?

Chemistry
I agree

Chemistry
I agree.

Chemistry
I don't understand it either. I don't see anything wrong with your reasoning.

Science
All hydrocarbons (and all of these are hydrocarbons) burn with O2 to form CO2 and H2O.

science
........PCl5 ==> PCl3 +Cl2 XCl2 = 0.40 Ptotal = 2 atm pCl2 = XCl2*Ptotal = 0.4*2 PPCl5 = Ptotal - PCl2 = ? Substitute into Kp expression and solve for Kp.

Chemistry
You need to know the solubility of KCl at 100 C and 30 C. You must have s tables or a graph that will give you that information. Supply that information and we can help.

Chemistry
You are right about 3. It does have the highest boiling poin; the key agrees with you. But the ketone has no to little chance of H bonding with another ketone molecule while the alcohol does which is why it is ketone<alcohol<aminoacid

chemistry
I have no idea. Reactive with what? No One cn answer this question.

Chemistry
Technically, the Henderson-Hasselbalch equation requires concentrations in mols/L; however, since the L will cancel we can use mols only as a short cut. pH = pKa + log (base)/(acid) YOu have pH and pKa, base is the unknown (in mols) and plug in 0.01 mol for acid. Show your ...

Science (Chemistry)
mols C = 49.2/12 = ? mols H = 9.68/1 = ? mols N = 19.19/14 = ? BUT C+H+N doesn't add to 100%. You made a typo or omitted something or the author of the problem forgot something.

Science
(100)^2 + (70)^2 = X^2 Solve for X.

Chemistry
Yes, Ca(OH)2 is much more soluble than Cu(OH)2 I look at it this. way with Cu salts. CuCl2, for example, the Cl is not hydrolyzed in aqueous solution while the Cu^+2 (actually the [Cu(H2O)4]^2+ is hydrolyzed

Chemistry
I would do with the rxn with H2O. CaO + HOH ==> Ca(OH)2 CuO + HOH --> Cu(OH)2 and Cu(OH)2 is not very soluble in water.

Chemistry
I would look at the van't Hoff equation. Here is a good discussion on Wikipedia. https://en.wikipedia.org/wiki/Van_%27t_Hoff_equation

Chemistry
Not really. The CCl4 solution will be single molecules, I think, Also, I know CH3COOH forms dimers (especially in the solid state) and in the liquid state the formula mass is somewhere between 60 and 90 indicating that some do and some don't. But I think whether dimers are...

Chemistry
I think it's because the CH3COOH is partially ionized in H2O and the percent ionization changes with the concentration of the acid.I was unsuccessful at finding the solubility of acetic acid in CCl4.

Chemistry
I don't think we can answer this unless we know how accurate the molar mass determination must be made; i.e., 5-10% or much more accurate like <1% error. Here are my thoughts to go with yours. I don't think A is a possibility and I'm confused with your first ...

Chemistry
And what do you think?

Chemistry
PV = nRT and solve for n. P = given in kPa. V = 50 L n = solve R = 8.314 T = 273 + 30 = ? You may also convert kPa given to atm by dividing by 101.325 kPa. If you do that then R must be in L*atm/mol*K and that is 0.08206

Chemistry
If you add enough Ag^+ you will ppt all of them; i.e., AgI, AgBr, AgOH (and that will quickly change to Ag2O). If you add Ag^+ drop wise, then AgI ppts first followed by AgBr, then AgOH in that order. Almost all of the AgI will be pptd by the time AgBr starts and almost all of...

chemistry
Removing 4s2 gives Mn^2+. Removing 4s2 and 3d5 gives Mn^7+. 3d electrons make the transition in row 3 from Ca to Ga.

chemistry
See your other post.

chemistry
Write the decomposition reaction for each. Balance the equation. Look up dHo formation for the products and reactants. dHrxn = (n*dHo formation products) = (n*dHo formation reactants). Compare the dHrxn values. OR, and this probably is simpler, look up the decomposition ...

chemistry
Think size of Li^+ vs Na^+.

chemistry
Here is Ca(NO3)2. https://www.google.com/search?q=decomposition+Ca(NO3)2&spell=1&sa=X&ved=0ahUKEwjIgfrfmKfVAhWiiFQKHe9CAPsQvwUIJSgA&biw=1005&bih=605 Google decomposition NaNO3 for that one.

Chemistry
I don't know what you mean by "strongest cation" especially when you follow it with Al(OH)3 and Fe(OH)3. If you're going down the OH^- path, I would pick K because KOH would be the strongest base but I may not have guessed right about where you're going ...

Chemistry
Then I think you answer is ok except that I would use odor to identify SO3 as a back up to the color.

Chemistry
You are asking, "Can we use O2 to ....". The odor of NO2 (and the brownish color) will identify NO2. Is SO3 bluish colored? I wasn't aware of that but it could be true and it certainly isn't brownish; however, the odor of SO3 is distinctly different than that...

Chemistry
To be honest about it I've never seen this done but I think the answer is yes. CaSO3 and CaCO3 in a fine suspension probably look alike. BTW, if I see it I usually don't answer questions posted using different screen names but I'll take a look at your other post by...

Chemistry
I don't believe 2,4,6-aniline exists. All of the amines listed, except for #4, are covalent amines and are weak bases. #4 is ionic like NaOH. Both TMAH and NaOH are strong bases. It helps us do a better job if you don't change screen names.

chemistry
Fe^3+(aq) + 3NaOH(aq) ==> Fe(OH)3(s) + 3Na^+

chemistry
A solution is made up of a solvent and a solute. When more solvent is added to any solution, the result is a diluted solution. The original solution was more concentrated.

Chemistry
OK. Now I understand. What you want is the total positive valence (or the total negative valence) in the compound Na2SO4. The total positive valence is 2 [that's +2*1= +2 = 2] which is the same as the total negative valence which is 2. The equivalent weight of Na2SO4 is ...

@ Gello 12; Ash; etc---Chemistry
You posted this same kind of question below under Ash. Please explain what you mean by this. Na has a valence and SO4^2- has a valence but the compound Na2SO4 (or AlCl3) has no valence. Asking for the positive valence of something clues us in on where you're going but you ...

Chemistry
I don't know that AlCl3 has any valence. Al is +3 and Cl is -1. AlCl3 is zero charged. Al has three electrons in the outside and it will lose those three electrons to become trivalent. Another way to look at it: All compounds are zero. Since Cl is -1 and there are three of...

chemistry
A Bronsted-Lowry acid donates a proton (a H^+); a Bronsted-Lowry base ACCEPTS a proton (a H^+). Just go through some reasoning. Since a H^+ is positive, I would think the OH^- would ACCEPT a proton so can't be OH^-. CCl4 has no charge nor protons so can't be. Mg(OH...

chemistry
Is that 1.7 g NH3 at 98% or 1.7 g NH3 @ 98%? I will assume you want 1.7 g NH3 but with 98% yield. N2 + 3H2 ==> 2NH3 mols NH3 = 1.7g/molar mass NH3 = 1.7/17 = 0.1 mol. That will require how many mols N2? That's 0.1 mol NH3 x (1 mol N2/2 mol NH3) = 0.1 x 1/2 = 0.05 mol N2...

Science
2KClO3 ==> 2KCl + 3O2 mols KClO3 = 1.225/molar mass KClO3 = ? mols O2 produced = mols KClO3 x 3/2 = ?

chemistry
See your other post.

chemistry
You really need to find the caps key and use it. o2 doesn't man anything to me. Example. CO is carbon monoxide; Co is cobalt; co is the abbreviation for company. 2C8H18 + 25O2 = 16CO2 + 18H2O How much CO2 should be produced by 4 moles octane at 100%? That's 4 mols ...

Chemistry
I believe that's the mole fraction of the other component, as stated, then times the vapor pressure of the benzene. Percent lowering = [(vp lowering-Po)/Po]*100 = ?

Chemistry
#1. NaHCO3 is not acidic. A solution of NaHCO3 has a pH of very close to 8.3 and that is basic although not highly basic. NaHCO3 + CH3COOH ==> CH3COONa + H2CO3, then the H2CO3, being unstable, decomposes to H2O and CO2 so you write it all at once to get NaHCO3 + CH3COOH ==&...

Chemistry
The best advice I can give is to use the activity series to order the reactivity (more reactive would mean less stable). You can Google activity series. However, many of the tables are abbreviated and will not list Ga, Tl and Sc so you may need to look at several to find a ...

chemistry
density CCl4 is 1.59 g/mL. It isn't 1.50 g. mass CCl4 = volume x density = 24,000 mL x 1.59 g/mL = ? grams. Then mols CCl4 = grams CCl4/molar mass CCl4 = ? Finally, there are 6.02E23 molecules in 1 mol of anything. Convert moles to # molecules.

Chemistry
Here is what I would do. The weight of the sample is 0.4903 x 0.9999 = 0.49025. mols C = 1.373/44.01 = ? mols H = 0.2791 x 2.016/18.02 = ? mols N = 0.1860/14.007 = ? Now find the ratio of each with no number being less than 1.00. The easy way to do that is to divide the ...

Chemistry - Stoichiometry/gases
I think you forgot the negative sign as in -802 kJ/mol.

To DrBob222
It is not possible to calculate Ka HAc from the data posted by Grace. The standard Ka value for HAc is used (e.g., from tables) and pH is calculated from that. As for errors, your first assumption is not right. (Ac^-) is not = to (H^+). It IS when you have a solution of HAc ...

Biochemistry
acetic acid = HAc sodium acetate = NaAc The way I interpret the problem as to how the author wants it solved is that you have 1L of solution containing 25 mM HAc and 30 mM NaAc; however, technically that isn't what it says to me. (HAc) = 0.01 M x (25/1000) = ? (NaAc) =0.03...

Science
You need to rework your post. As written it makes no sense to me.

science
https://www.google.com/search?q=define%3Aphotosynthesis&ie=utf-8&oe=utf-8

chemistry
Wouldn't that be 3*85 = ?

chemistry
2H2 + O2 ==> 2H2O mols H2 = 2.3/2 = 1.15 mols O2 = 29/32 = 0.906 Convert mols each to mols product. 1.15 x (2 mols H2O/2 mols H2) = 1.15 0.906 x (2 mols H2O/1 mol O2) = ? The smaller amount of product is the product formed and the reagent responsible for that amount is the ...

biochemistry
5 mM x (250/500) = 2.5 mM = 0.0025 M Then (H^+)(OH^-)= 1E-14 and solve for H^+; convert to pH. In pure H2O the (OH^-) is 1E-7 but that isn't enough to significantly affect the total OH^-.

Science
I may have missed something but I don't get the right answer of 2.08 J/g*C. Please check your numbers.

Chemistry
See your previous post. Post you work if you still have questions. It's the same concept. Four steps. 1. Write and balance the equation. 2. Calculate mols of what you have. That's the H2SO4. 3. Using the coefficients in the balanced equation, convert mols of what you ...

Chemistry
Ca(OH)2 + 2HNO3 ==> Ca(NO3)2 + 2H2O mols HNO3 = M x L = ? Look at the coefficients. mols Ca(OH)2 = 1/2 mols HNO3. Then M (Ca(OH)2 = mols/L = ?

chemistry
base = NaAc = (grams/molar mass)/L acid = HAc = 1M x (9/100) = ? Substitute into the Henderson-Hasselbalch equation and solve for pH. Post your work if you get stuck.

Chemistry
hydrogen sulfide, H2S

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