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Posts by DrBob222

Total # Posts: 54,522

Chemistry
Q = (products)/(reactants) K = (products)/(reactants) reactants ==> products You want products to be higher so is it B or D

chemistry
The Kc is 100 for what reaction? Is it 2SO3 ==> 2SO2 + O2 or the reverse?

chemistry
CH4 + 2O2 ==> CO2 + 2H2O mols CO2 = 11,000/molar mass CO2 = ? Using the coefficients in the balanced equation, convert mols CO2 to mols CH4. Now grams CH4 = mols CH4 x molar mass CH4

Chemistry
Yes. (0.05/30)*100 = ?

Chemistry
The definition gives you the information. The Wikipedia link will give you details. https://www.google.com/search?q=solvay+provess&ie=utf-8&oe=utf-8

Inorganic Chemistry
That is essentially impossible on this forum. I suggest you Google the subject.

Chemistry
I gave you the two balanced half reactions yesterday. Why do I need to this again? C goes from +2 on the left to +4 on the right. Cl is -1 on the left and 0 on the right. Both are oxidized. Nothing wrong with that.

Chemistry
We don't know what the experiment is.

chemistry
You can't make 150 ppm Cu. You can make 150 ppm Cu^2+ 1 ppm = 1 mg/L. 150 ppm = 150 mg/L. So weigh 150 mg Cu, dissolve in a little HNO3, make to the mark in a 1 L volumetric flask with DI water, mix thoroughly, stopper, bingo.

Chemistry
I agree with Bob P but your answer, with that many significant figures, could be counted wrong. b. is right. Same comment about s.f.

Chemistry G.12
I agree with you for a. It TAKES energy to break the crystal lattice. Heat is given off when hydrates are formed. b. I also agree with hydration energy for b. If more energy is given off in forming a hydrate that should increase the solubility.

Chemistry
Since the density is 1.00 g/mL, that makes the mass of solution the same as the volume of the solution. My old standby is to know that 1 ppm = 1 mg/L. 13.7 g pesticide = 13.7 x 1000/250 = approx 55 mg/L = approx 55 ppm. That is the same as approx 55,000 ppb.

CHEMISTRY
MnO4^- + 8H^+ +5e = Mn^2+ + 4H2O 2CHCl3 + 4H2O==> 3Cl2 + 2CO2 + 10 H^+ + 10e Multiply equation 1 by 10; equation 2 by 1 and add,

Chemistry
See your other post.

ap chemistry
It helps us help you if you pick a name, as writeacher suggests, and stick with it. B is not true. All of the others are ok

ap chemistry
K = (products)/(reactants) Let's just say P = 1 and R = 1, then K = 1/1 = 1 and Q = K Now let's change the P and R to say P = 2, then Q = 2/1 so Q>K and P is higher; R is smaller. If P<1, then Q<K and R is higher; P is smaller. Pick the right answer from this...

chemistry -3.2.4
I answered this for you yesterday.

chemistry - 3.1.6
......2HI ==> H2 + I2 I.....1.60.....0....0 C.....-2x......x....x E....1.60-2x...x....x Substitutethe E line into the Keq expression and solve for x.

Chemistry
Is that 0.2512 M stock? I will assume it is. mols NaOH = M x L = ? mols HCl = mols NaOH (since 1 mol HCl = 1 mol NaOH in the balanced equation). M HCL stock = mols/L. You know M and you know mols, solve for L and change to mL if desired.

chemistry - 4.1.4
No. (H^+)(OH^-) = Kw = 1E-14. You know OH, solve for H.

chemistry
NaOH is a strong base.

chemistry
A is not right. K = ([products)/(reactants)

Chem
6.5g/3.0 mL = ?

Chem
CH3COONa.3H2O ==> CH3COO^-(aq) + Na^+(aq) + 3H2O

chemistry
You include but don't "ADD" i. For KNO3 i = 2 delta T = i*Kf*m or delta T = i*Kb*m

Chemistry
I don't get "converted to solid enthalpy"

Chemistry
So why not tell us what you did? That way we could help. This way you just want the answer.

Chemistry
mols C = 12/12 = ? mols Mg = 12/24.3 = ? 1 mol of anything contains 6.02E23 atoms.

chemistry
You can look this up on Google.

chem
w = wavelength 1/w = 1.0973E7(1/1 - 1/n^2). Convert w to meters and solve for n. That gives you n to which the electron moves from the ground state.I get n = 7 Then 1/w = 1.0973E7(1/n^2 - 1/7^2). Convert 2165 nm to m and solve for n. That looks like about 4 to me.

chemistry
I think this is a nonsense question although I suspect you have typed it as it was presented to you. I think the author of this problem probably expects you to answer that you expect more solid than the ion (based on the small number for Ksp); however, the amount of solid AgCl...

chemistry 102
You don't have enough information. I don't know what you did in the experiment.

chemistry
Not enough information to answer. You need to explain what you did.

chemistry
Finding Ka values for these salts is difficult. Intuitively I would think AlCl3 would be more acidic; however, I found Ka for FeCl3 = 2E-3 and for AlCl3 = 1.2E-5. From that information FeCl3 is the stronger. I could find no information about BeCl2 or NiCl3. Sorry I can't ...

chemistry
You started with 25g solution and recovered 4g of salt. So the solubility is 4g per 25g. That would be 4 x 100/25 = solubility in 100 g.

chemistry
what table?

chemistry
I see a lot of posts here. No indication of what you think the answer is. This is a homework help site and not a homework do site. If you have something you don't understand I shall be glad to help you through it if you explain in detail what you're having trouble with...

Chhem
the temperature of the salt water

Chemistry
1.5 + 12.0 = ?

Biochemistry
You should use k1. You are starting with NaHCO3, not Na2CO3. And (base) + (acid) = 0.5M For buffers you want to use a pKa within +/- 1 of the desired pH.

Chemistry
2Na + H2SO4 ==> Na2SO4 + H2 single displacement I'll leave the other one for you. products are Mg3(PO4)2 + H2O It is a double displacement reaction.

Chem
Ag^+(aq) + Cl^-(aq) ==> AgCl(s)

chemistry
Step 1. Write and balance the equation. Ba(OH)2 + 2HCl ==> BaCl2 + 2H2O Step 2. mols Ba(OH)2 = M x L = ? That's approx 0.0046 but you need an accurate answer. Step 3. Using the coefficients in the balanced equation, convert mols Ba(OH)2 to mols HCl. That's approx 0....

Chem
This is a double displacement (or double replacement) reaction. The Mg combines with the Cl to make MgCl2; the OH combines with the H to make H2O.

chemistry
The best answer here is A but that isn't always correct.

chemistry
Generally A but that isn't always correct.

chemistry
Technically this question can't be answered without knowing that the salts have the same ratio of cations to anions.

chemistry
Write the ionization expression for HAc. HAc ==> H^+ + AC^- now K = (H^+)(Ac^-)/(HAc) Now if NaAc is added, that increases the Ac^- (the common ion effect), that shifts the equilibrium to the left. What happens to the H^+ and how does that affect the pH. By the way, this is...

chemistry
I can write a Keq for all of them.

chemistry
A. This is the definition of equilibrium.

chemistry
A definition. We will be glad to critique your thoughts. Looking them up will help you remember; having us do them for you will not.

chemistry
C'mon. What is your problem with this? It a definition for K. You need to know the definition and you can do these yourself. Also, you need to use arrows. ==> or --> or >>>.

chemistry
K = (H2O)^2/(H2)^2(O2) In increase in P means the reaction will shift to the side with fewer mols. So increase in P shifts to the right; therefore, a decrease must shift to the left. There are two answers for left (A and D). Can you figures with Q is larger or smaller.

chemistry
Keq = (Fe^2+aq)(Cl^-aq)^2/(FeCl2). Some may argue that the denominator of FeCl2 should not appear; however, by definition it is 1 and like to put it in.

Chemistry
0.326 g = mass FeCl2.xH2O -0.254 g = mass FeCl2 -------------- 0.072 g = mass xH2O mols FeCl2 = grams/molar mass = ? mols H2O = grams/molar mass = ? Now find the ratio of 1 mol FeCl2 to H2O and round to a whole number. That whole number will be x. The easy way to do that is ...

Chemistry
delta T = Kf*molality You know delta T and Kf, solve for m. molality = mols/kg solvent. You know m and kg solvent, solve for mols. Then mols = grams/molar mass You know mols and grams, solve for molar mass.

Chemistry
All you gave was a number. I can't tell you what you're doing wrong since you didn't show your work. The right answer is in the ball park of 560 g

chemistry
mols CaCl2 = grams/molar mass. mols Cl^- = twice that since there are 2 mols Cl^- for every mols CaCl2. Then there are 6.02E23 Cl^- for every mol Cl^-.

chemistry
Here is a "balanced" equation. 2C2H2 + 5O2 ==> 4CO2 + 2H2O

Chemistry
I2 is diatomic. Zn + I2 ==> ZnI2 Use 1 mol I2 = 1 mol ZnI2. If you wanted mols I ATOMS, then 1 mol ZnI2 = 2 mol I atoms.

Science
Without knowing the initial procedure or the updated procedure, no one can help you.

Chemistry
Zn + 2HCl ==> H2 + ZnCl2 mols Zn = grams Zn/atomic mass Zn = ? Using the coefficients in the balanced equation, convert mols Zn to mols HCl. That will be mols Zn x 2 = mols HCl. Then M = mols/L. You know M of HCl, mols HCl, solve for L HCl and convert to mL

Physical Chemistry
a. [mass Au x specific heat Au x (Tfinal-Tinitial)] + [mass Ag x specific heat Ag x (Tfinal-Tintitial)] = 0 Substitute and solve for Tfinal. b. q = [mass Au x specific heat Au x (Tfinal-Tinitial)] OR q = ([mass Ag x specific heat Ag x (Tfinal-Tinitial)] q is the same for each ...

chemistry
I think you are right that OMe is a ortho/para directing group. I think the CO2R is an ester and esters are meta directing.

Chemistry
M = mols/L M = 1.5 mols/1.5 L = 1.0 M

Chemistry (equilibrium)
Since the dH reaction is +312 kJ, that means the reaction is endothermic so I would write it as C2H6 + heat = C2H2 + 2H2 So if T is decreased, rxn shift to the left. (Rxn uses heat to go to the right; take heat away it moves to the left). Add He at constant volume. If volume ...

chemistry help
Emma, you didn't like my answer? http://www.jiskha.com/display.cgi?id=1473523976

Chemistry
If it exists I would name it nitrogen trioxide.

chemistry
I don't think there is an answer. A is true most of the time but not always. It depends, somewhat, upon how acids and bases are defined. D is a true statement but that isn't neutralization. B and D are true, also, but those aren't neutralization reactions.

chemistry
I don't understand how the answer can be D. There is no water in the reaction. What you want to do is to shift the equilibrium to the left (remove the OH^-) and you can do that by adding an acid so I would choose B.

chemistry
I would go with B.

chemistry
I don't think so. H2 + O2 ==> 2H2O If P increases, it shifts to side with fewer moles of gases. There are 3 mols on the left; two moles on the right so for increase P it shifts to the right. A decrease in P must shift to the left.

chemistry
You could save a lot of time by using this: 2H2 + O2 ==> 2H2O. Everyone knows that the number two following H and O are subscripts. We CAN write them as subscripts but no one wants to take the time to do it. 2H2 + O2 ===> 2H2O Here is the rule to follow: An increase in ...

chemistry
Equilibrium is reached when the forward reaction rate equals the reverse reaction rate.

chemistry
I'm having trouble following the question. Please rephrase, don't omit words, and please no abbreviations; e.g. I have no idea what PP end point is.

Biochm I
I agree

chemistry
All are right

chemistry
EDTA complexes CaCO3. Here is explanation. http://www.austincc.edu/dsackett/CHEM1412/lab/1412exp47.pdf

Chemistry
You look at the graph and pick the midpoint (the inflection in the graph). At that point, (HA) = (A^-) and pH = pKa.

Chemistry urgent please
Sorry, I know nothing about the Japanese pharmacopeia.

Chemistry urgent please
If this is a qual test you need have enough dil HNO3 to make the solution slightly acid. Add dil HNO3 to the solution dropwise until it is acid to litmus paper. The actual amount you need to add will be determined by the amount of NaOH present in the test.

Chemistry
P*molar mass = density x RT

Science
Are these three question? What do you want? Are these multiple choice?

Chemistry(please check my answer)
right

chemistry
CH4 + 2O2 ==> CO2 + 2H2O mols CH4 = grams/molar mass = ? Using the coefficients in the balanced equation, convert mols CH4 to mols CO2, then again convert mols CH4 to mols H2O. Then convert mols CO2 and mols H2O to grams of each. g CO2 = mols CO2 x molar mass CO2 g H2O = ...

chem help!
Reactions with dG negative are spontaneous.

chem help!
dG = -RTlnK If dG is - then K is + and a +K means products are greater than reactants. Products are in the numerator; reactants in the denominator.

Chemistry
No details. Can't answer.

Chemistry
Note the correct spelling of Celsius. Probably something is missing. With no volume CO listed you can't give a volume of O2 required. However, with no volume CO listed, you could answer that the required amount of O2 required is 1/2 the volume of CO used.

chemistry
I read all of these posts. Almost all are solved with the Henderson-Hasselbalch equation, or some variation of the HH equation. I think all of them are buffer problems. I suggest you pick one of them; e.g. the carbonate/bicarbonate problem, show what you have done or what you ...

chem
pH> = basic pH<7 = acid pH=7 = neutral

chem
I don't like any of the answers but if I had to pick one I would chose A.

chem
I don't agree with you. C and D are smaller numbes than A or B

chem
http://www.chem.purdue.edu/gchelp/howtosolveit/Kinetics/IntegratedRateLaws.html

chem
http://bouman.chem.georgetown.edu/S02/lect4/lect4.htm

chem
https://en.wikipedia.org/wiki/Four-stroke_engine

Chemistry
https://en.wikipedia.org/wiki/Oncotic_pressure

chemistry
rate = k(NO)(O3) rate = 1.5E7(NO)(O3)

chemistry
See your other post. Please use the same screen name.

chemistry
I believe you need to read and correct the question. Also let me point out that nacl and h2so4 don't mean anything to me. Find the caps key and use it.

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