Saturday
December 10, 2016

Posts by DrBob222

Total # Posts: 53,766

CHEMISTRY
Generally that is NaOCl.
September 19, 2016

Chemistry
initial (N2) = 1/10 = 0.1 initial (H2) = 1/10 = 0.1 equilibrium (H2) = 0.4/10 = 0.04 .......N2 + 3H2 ==> 2NH3 I.....0.1..0.1......0 C.....-x....-3x.....+2x E..0.1-x...0.1-3x...2x The problem tells that 0.1-3x = 0.04 so x = 0.02. That allows you to calculate composition of ...
September 19, 2016

oops. here is Kp--Chemistry
Find Kp by Kp = Kc(RT)^delta n. Remember S is a solid and not a gas.
September 19, 2016

Chemistry
......H2S ==> H2 + S(s) I.....0.7.....0.....0 C.....-x......x.....- E...0.7-x.....x.....- NOTE that S is a solid and isn't in the Kc expression: Kc = (H2)/(H2S) Substitute the E line into Kc expression and solve for x = (H2) in mols/L. The problem asks for grams S and ...
September 19, 2016

Chemistry
Use PV = nRT and solve for p= pressure at the initial conditions listed. You can go through the math but I've estimated initial p = 0.05 atm. Of course you need a more accurate number than that. ......NOBr ==> NO + 1/2 Br2 I....0.05......0........0 C.....-p.......p...
September 19, 2016

Camestry
mass = volume x density. Substitute and solve.
September 18, 2016

Chemistry
There's the long way, a shorter way, and a short cut that isn't taught in schools anymore. Long way. mols CaCl2.6H2O = grams/molar mass = ? mols CaCl2 = mols CaCl2.6H2O since there is 1 mol CaCl2 in 1 mol CaCl2.6H2O Finally, g CaCl2 = mols CaCl2 x molar mass CaCl2. ...
September 18, 2016

Chemistry
CaCO3 + 2HCl ==> CaCl2 + H2O + CO2 mols HCl = M HCl x L HCl = ? Using the coefficients in the balanced equation, convert mols HCl to mols CaCO3. That will be mols HCl x (1 mol CaCO3/2 mols HCl) = mols HCl x 1/2 = ? Then convert mols CaCO3 to grams. g CaCO3 = mols CaCO3 x ...
September 18, 2016

Chemistry
I don't understand the questions since some have units and others don't. For first one, I have 2.865E4 x 1.47E3 = 4.21155E7. The first number has 4 s.f. and second has 3 s.f. The rule in multiplying is that the final answer may have no more s.f. than any of the numbers...
September 18, 2016

Chemistry
Is that concn in M (mols/L). I will assume so. mols NaCl = 73.28/58.44 = ? mols Cl = same as mols NaCl Then M Cl = (mols/0.862L) = ?
September 18, 2016

Chemistry
I don't think so. 1E5 mL = 1E5 cc = 1E5 cm^3. There are 100 cm in a m; therefore, 1E5 cm^3 x (1 m/100 cm)^3 = ? m^3 which I think is 0.1 m^3.
September 18, 2016

Chemistry
mols CuCl2 = g/molar mass = 0.00628/molar mass CuCl2 = ? Then there are two Cl^- for every mols CuCl2.
September 18, 2016

AP CHEM
Separate the molecular equation into ions using the following rules. 1. If the substance is soluble, show the ions with (aq) after + and - ions. 2. If a gas so that as a molecule and write (g) after it. 3. If a solid, show it as the molecule and write (s) after it. 4. If a ...
September 18, 2016

Chemistry
As far as I can tell, dolomite is a 50/50 mixture (mostly) of CaCO3 and MgCO3. CaCO3 ==> CaO + CO2 MgCO3 ==> MgO + CO2 5.424/2 = approx 2.7 g MgCO3 and approx 2.7 g CaCO3. Starting with these amounts and the equations above, solve for grams CaO and grams MgO, then add ...
September 18, 2016

Chemistry
Mn changes from +7 on the left to +2 on the right. S(from H2S) changes from -2 on the left to 0 on the right. Show your work if you get stuck.
September 18, 2016

CHEMISTRY
Two equations which you solve simultaneously. KH2PO4 is the acid(A); K2HPO4 is the base(B) pH = pKa + log B/A So equation 1 is 7.20 = 7.21 + log B/A Solve for B/A = ? Equation 2 is A + B = 1 M. (The problem tells you the buffer is to be 1 M. I like to work in millimols and you...
September 18, 2016

Chemistry
I'm somewhat confused on how the solubility is being measured; however, this is what I would do. I suspect this is NOT what your prof wants. I would take the 75 C saturated solution. I assume the solubility is 155 g/100 g H2O so that solution will weigh 255 g and contain ...
September 18, 2016

Chemistry
Adding CuSO4 is adding a common ion (the Cu^2+) so the reaction will shift to the right producing more CuS. Adding Na2SO4 will do nothing. There is no common ion in Na2SO4 and there is nothing to react. So the answer is ........
September 18, 2016

Chemistry
I agree with you.
September 18, 2016

Chemistry
(855/180)mols C6H12O6 x (6 mols CO2/1 mol C6H12O6) = (855/180) mols C6H12O6 x (6/1 = ?mols CO2
September 18, 2016

Chemistry
C6H12O6 + 6O2 ==> 6CO2 + 6H2O mols C6H12O6 = grams/molar mass = ? Using the coefficients in the balanced equation, convert mols C6H12O6 to mols CO2. Then grams CO2 = mols CO2 x molar mass CO2.
September 18, 2016

chemistry
mols = M x L = ? Then mols = grams/molar mass. You know mols and molar mass, solve for grams.
September 18, 2016

Chemistry
110.810 g = liquid + mass cyl -82.450 g = mass empty cylinder -------------- 28.26 g = mass liquid volume liquid = 50 mL density = mass/volume. Check all of the calculations.
September 17, 2016

Chemistry
There are 454 g/lb There 28317 mL/cubic foot You work this like the last one.
September 17, 2016

Chemistry
2.36E4 s x (1 min/60s) x (1 hr/60 min) x (1 day/24 hrs) = ?
September 17, 2016

Chemistry
pH = -log(H^+) Substitute and solve for H^+
September 17, 2016

Chemistry
C is not right. A buffer consists of EITHER: a. a weak acid with a salt of that weak acid OR b. a weak base with a salt of that weak base. C is a STRONG base and its salt. B is a strong acid D is a strong acid.
September 17, 2016

Chemistry
Neutral solutions have (H^+)=(OH^-) = 1E-7.
September 17, 2016

Chemistry
Q = (products)/(reactants) K = (products)/(reactants) reactants ==> products You want products to be higher so is it B or D
September 17, 2016

chemistry
The Kc is 100 for what reaction? Is it 2SO3 ==> 2SO2 + O2 or the reverse?
September 17, 2016

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
September 17, 2016

Chemistry
Yes. (0.05/30)*100 = ?
September 17, 2016

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
September 16, 2016

Inorganic Chemistry
That is essentially impossible on this forum. I suggest you Google the subject.
September 16, 2016

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.
September 16, 2016

Chemistry
We don't know what the experiment is.
September 16, 2016

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.
September 16, 2016

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.
September 15, 2016

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.
September 15, 2016

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.
September 15, 2016

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,
September 15, 2016

Chemistry
See your other post.
September 15, 2016

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
September 15, 2016

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...
September 15, 2016

chemistry -3.2.4
I answered this for you yesterday.
September 15, 2016

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.
September 15, 2016

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.
September 15, 2016

chemistry - 4.1.4
No. (H^+)(OH^-) = Kw = 1E-14. You know OH, solve for H.
September 15, 2016

chemistry
NaOH is a strong base.
September 15, 2016

chemistry
A is not right. K = ([products)/(reactants)
September 15, 2016

Chem
6.5g/3.0 mL = ?
September 14, 2016

Chem
CH3COONa.3H2O ==> CH3COO^-(aq) + Na^+(aq) + 3H2O
September 14, 2016

chemistry
You include but don't "ADD" i. For KNO3 i = 2 delta T = i*Kf*m or delta T = i*Kb*m
September 13, 2016

Chemistry
I don't get "converted to solid enthalpy"
September 13, 2016

Chemistry
So why not tell us what you did? That way we could help. This way you just want the answer.
September 13, 2016

Chemistry
mols C = 12/12 = ? mols Mg = 12/24.3 = ? 1 mol of anything contains 6.02E23 atoms.
September 13, 2016

chemistry
You can look this up on Google.
September 13, 2016

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.
September 13, 2016

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...
September 12, 2016

chemistry 102
You don't have enough information. I don't know what you did in the experiment.
September 12, 2016

chemistry
Not enough information to answer. You need to explain what you did.
September 12, 2016

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 ...
September 12, 2016

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.
September 12, 2016

chemistry
what table?
September 12, 2016

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...
September 12, 2016

Chhem
the temperature of the salt water
September 11, 2016

Chemistry
1.5 + 12.0 = ?
September 11, 2016

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.
September 11, 2016

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.
September 11, 2016

Chem
Ag^+(aq) + Cl^-(aq) ==> AgCl(s)
September 11, 2016

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....
September 11, 2016

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.
September 11, 2016

chemistry
The best answer here is A but that isn't always correct.
September 11, 2016

chemistry
Generally A but that isn't always correct.
September 11, 2016

chemistry
Technically this question can't be answered without knowing that the salts have the same ratio of cations to anions.
September 11, 2016

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...
September 11, 2016

chemistry
I can write a Keq for all of them.
September 11, 2016

chemistry
A. This is the definition of equilibrium.
September 11, 2016

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.
September 11, 2016

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 >>>.
September 11, 2016

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.
September 11, 2016

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.
September 11, 2016

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 ...
September 11, 2016

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.
September 11, 2016

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
September 11, 2016

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^-.
September 11, 2016

chemistry
Here is a "balanced" equation. 2C2H2 + 5O2 ==> 4CO2 + 2H2O
September 11, 2016

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.
September 11, 2016

Science
Without knowing the initial procedure or the updated procedure, no one can help you.
September 10, 2016

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
September 10, 2016

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 ...
September 10, 2016

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.
September 10, 2016

Chemistry
M = mols/L M = 1.5 mols/1.5 L = 1.0 M
September 10, 2016

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 ...
September 10, 2016

chemistry help
Emma, you didn't like my answer? http://www.jiskha.com/display.cgi?id=1473523976
September 10, 2016

Chemistry
If it exists I would name it nitrogen trioxide.
September 10, 2016

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.
September 10, 2016

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.
September 10, 2016

chemistry
I would go with B.
September 10, 2016

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.
September 10, 2016

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