Tuesday
August 4, 2015

Posts by drbob222


Total # Posts: 49,635

URGENT CHEMISTRY
Why do I want to do all of your home work? What don't you understand about this? It's products divided by reactants with coefficients for each material becoming the exponent for that material. For example, f is K = (SO3)^2/(SO2)^2(O2)
August 4, 2015

Chemistry
Your two equations are not balanced and we can't do anything with them until they are. For example, #1. You have 2A on the left and 2A on the right. You have 2/3 C2 which is 4/3 C on the left but 3 on the right. Are you sure that isn't 2A + 3/2 C2 = A2C3? And #2 would ...
August 4, 2015

Chemistry
I don't think you read my response. Re-read. mols C = grams/atomic mass C.
August 3, 2015

Chemistry
If that is all that's confusing you the easiest way to take care of it is that you don't start with 5.00 kg but 5.00 kg x 0.962 = ? kg and I would change that to grams. mols C = grams/atomic mass C = ? Then 395 kJ/mol x # mols = ? kJ released. Personally I don't ...
August 3, 2015

chemistry
See your earlier post below.
August 3, 2015

Chemistry
q = mass H2O x heat fusion You know mass H2O in grams, look up the heat fusion in J/g and solve for q in joules. The problem actually is not complete because it doesn't tell you the temperature of the water being sprayed. I think it assumes you will assume the temperature ...
August 3, 2015

chemistry
I have looked under reactions of azomethine, reaction of 4-aminotoluene and vanillin, reaction or p-aminotoluen and vanillin, and other variations and came up with nothing. You might have better luck trying some variation of those on Google. Sorry about that. I did find these ...
August 3, 2015

chemistry
You want me to write up your experiment. No thanks.
August 3, 2015

Chemistry
You may be overwhelmed with information that is not needed. You don't care what it's being used for nor even what it is. All you need to do is to convert kJ to calories. There are 4.184 J in 1 calorie and 1000 J in 1 kJ. So 1367 kJ x (1000 J/1 kJ) x (4.184 J/cal) = ? ...
August 3, 2015

Urgent chemistry
Something is missing here. You saw that answer from Sarah and I explained that part. What do you not understand about this? All you need to do is reason out the law. In fact I answered what P will do (both increase and decrease). I explained about adding NH3. Why won't the...
August 3, 2015

Chemistry
2 is C for sure. #1 is not that easy I don't think. The question asks about total energy but provides only the fact it is endothermic. Endothermic tells you that the reaction absorbs heat from the surroundings in order to occur. It doesn't say anything about the total ...
August 3, 2015

Chemistry
If you are having a problem balancing these you need to tell us what the problem is. All appear to be balanced to me.
August 3, 2015

Chemistry
That's right. Increasing P shifts to the side with fewer mols OF GAS. There are 4 mols on the left and 2 on the right so increasing P shifts to the right; decreasing P shifts it to the left.
August 3, 2015

Chemistry
In common words, Le Chatelier's Principle tells us that when a system in equilibrium is subjected to a stress, it will shift to undo what we did to it. So look at the equation. 3 H2(g) + N2(g) <- -> 2NH3(g) + heat Adding NH3. So the reaction will try to use up NH3 to...
August 3, 2015

Chemistry
See your other post.
August 3, 2015

Equilibrium
In the problem, yes. In real day to day work, you must know the temperature for which the K is given because K is different at some other temperature.
August 3, 2015

Equilibrium
You work this EXACTLY as you did for the previous problem. The 852 never enters into it EXCEPT that the Keq you calculate will be good ONLY for that temperature.
August 3, 2015

Chemistry
Which oxide? Any one of the several that are known? I will assume NO. Note the following: For H2O. (0.126g H2/2 H atoms) x 16 = 1.00 g oxygen and (0.216g H2/3 H atoms) x 14 = 1.00 g N, so (1.00/14) x 16 = ? g N to form NO.
August 3, 2015

Chemistry
See your post above.
August 3, 2015

org chem
If you are talking about a NON-VOLATILE SOLUTE you are right. It may or may not be true with a volatile solute and volatile solvent. When a non-volatile solute dissolves in a volatile solvent, three things happen. a. The vapor pressure of the solvent is lowered, b. The boiling...
August 2, 2015

org chem
The partition constant, also called the distribution constant, is a number, similar to Ksp and Keq that defines the solubility of a solute between two immiscible solvents such as water and hexane.
August 2, 2015

Chemistry
Ba(OH)2 + 2HCl ==> 2H2O + BaCl2 mols Ba(OH)2 = M x L = ? mols HCl = M x L = ? which is twice that of Ba(OH)2 so the two exactly neutralize each other. q = heat generated = mass H2O x specific heat H2O x (Tfinal-Tinitial) mass H2O = 65 + 65 = 130 mL = 130 g specific heat H2O...
August 2, 2015

org chem
Great. Glad to help. You must be careful about "bunching up" ethyl, propyl, butyl groups. When you do that you forget about counting the carbons in those bunched up groups to make the longest chain--so you end up getting smaller chains than you would do otherwise.
August 2, 2015

org chem
Draw it out--which I can't do on this forum. Then count the LONGEST chain. It will be a hexane so it will be named as a 3-methylhexane.
August 2, 2015

chemistry
Are you talking about 20% w/w/ or 20% w/v? I will assume you mean 20% w/w which means 20 g ethylene gycol in 100 g solution. So that is 20 g ethylene glycol in 80 g H2O. n H2O = g/molar mass = ? n ethylene glycol = grams/molar mass = ? total mols = n H2O + n ethylene gycol ...
August 2, 2015

science
Your question makes no sense.
August 1, 2015

chem
% w/v = (grams solute/mL solution)*100 =
August 1, 2015

Chemistry
Anonymous points out that you don't have an equation; however you can use an ionic equation of 2Ag+ + CrO4^2- ==> Ag2CrO4 Assuming you have enough chromate to use all of the AgNO3, you can produce 6 mols AgNO3 x (1 mol Ag2CrO4/2 mols AgNO3) = ? 2AgNO3 + Na2CrO4 ==> ...
August 1, 2015

Chemistry
I couldn't have said it better.
August 1, 2015

chemistry
Probably you want to know the (H^+). mols of the 3M HNO3 = M x L = ? mols of the 4M HNO3 = M x L = ? M of the mixture is M = total mols/total L If you want to know the pH it is pH = -log(HNO3)
August 1, 2015

Organic chemiststry
As my organic prof used to say, "To the general public there are three kinds of alcohol; the kind you drink (ethyl alcohol), the kind you drink and go blind (wood or methyl alcohol) and the kind you rub on your back (rubbing alcohol or isopropyl alcohol)." The point ...
August 1, 2015

Organic chemistry
See your other post.
August 1, 2015

Chemistry
HF<HCl<HBr<HI<HClO4 HF is the weakest; HClO4 the strongest.
August 1, 2015

chemistry
The H on the right hand side of HCOOH is the active H (as in HCl etc) and from there it's a usual acid/carbonate reaction. HCOOH + CaCO3 ==> Ca(HCOO)2 + H2O + CO2 You balance.
July 31, 2015

College Algebra
Isn't this just a matter of punching the numbers into your calculator?
July 31, 2015

Emergency chemistry
I see only two questions you posted and I responded to them almost an hour ago.
July 30, 2015

Science
http://www.jiskha.com/display.cgi?id=1438290333
July 30, 2015

Science
You posted this yesterday and received a reply. Why are you post again?
July 30, 2015

chemistr
The beginning energy, the ending energy, the difference between beginning and end.
July 30, 2015

Chemistry
Solids don't enter into the equilibrium constant expression; therefore, ignoring those the expression is Keq = (BO2) Since the (BO2) at equilibrium is given as 2.0 M in the problem, then K must be .....?
July 30, 2015

Chemistry :(
Le Chatelier's Principle tells us that if we do something to affect the equilibrium of a reaction, it will try to undo what we did to it. I would rewrite the equation as 3H2(g) + N2(g) ==> 2NH3(g) + heat Adding a catalyst NEVER changes the equilibrium although it ...
July 30, 2015

Chemistry
See your other post.
July 30, 2015

what changes?--Chemistry

July 30, 2015

chemistry
Surely you don't mean 0.01 g/mL density. I might believe 1.01. Steps to follow after you know the density. mass solution = 1000 mL x density = ? mass solution - 10 g H2SO4 = ? g H2O Then mols H2SO4 = 10/molar mass = ? mols H2O = grams/molar mass = ? XH2SO4 = mols H2SO4/...
July 30, 2015

Chem
I'm not sure what you want when you say describe. Heat will flow from the 59 C metal to the 25 C water. The metal will cool; the H2O will warm. The final T of both will be less then 59 and greater than 25 You can calculate the final T of both by substituting and solving ...
July 30, 2015

Physical sciences
You need to provide more details. This seems to just part of the problem.
July 30, 2015

Chemistry
Carbonate is -2 so Ag must be +1 each.
July 29, 2015

Chemistry
I responded at the original post. I was busy answered those million questions posted by Mindy so it took a little while to get back to your question.
July 28, 2015

Chemistry
See this link. http://www.jiskha.com/display.cgi?id=1438134034
July 28, 2015

Chemistry
So show what you did and I shall be happy to check it for you. First, however, look at the previous problem. This problem is actually the same as the previous problem but worked twice in the same problem. Have you identified the limiting reagent?
July 28, 2015

Chemistry
I don't buy Paula's answer.
July 28, 2015

Chemistry
mols CCl4 is correct at 104. Now you want to go to step 2 and convert mols CCl4 to mols CS2. That is done this way using the coefficients in the balanced equation. 104 mols CCl4 x (1 mol CS2/1 mol CCl4) = ?
July 28, 2015

Chemistry
The problem tells you the reactants and products. Copy those down, then balance it. CS2 + 3Cl2 ==> CCl4 + S2Cl2 Then the problem part. 16 kg = 16,000 g mols CCl4 = grams CCl4/molar mass CCl4 = ? Using the coefficients in the balanced eaquation, convert mols CCl4 to mols CS2...
July 28, 2015

Chemistry
I did the same thing as Enrique with initial (H2) = 0.510; (I2) = 0.173; (HI) = 0, did the set up and my final concentrations are not close to any numbers listed. You know the negative numbers can't be right.
July 28, 2015

Chemistry
I don't think so. 4.65 g H2 x (1 mol/2g) x (1/4.55L) = not 0.0037 or perhaps I've misinterpreted your work. And what's with the - signs?
July 28, 2015

Chemistry
Actually, I think Enrique is talking about the first equilibrium. After that, you will need to set up a second one with the added 1.25 M I2 and run through a second set of calculations. Post your work as far as you can get and explain what you don't understand if you get ...
July 28, 2015

chemistry
PV = nRT
July 28, 2015

chemistry
No. I see P1 of 567 and V1 of 136. On the right I see 421 and all of those are in the right place. Where did the 183 come from? That's what you're solving for and is the answer. The way you have it set up there is no unknown and I have no idea how you ended up with 4,...
July 28, 2015

chemistry
P1V1 = P2V2. You can use this because T is constant. However, since T is given, you can use (P1V1/T1) = (P2V2/T2) and come out with the same answer.
July 28, 2015

chemistry
Always start with a balanced equation. You have that. Convert 54.92 g KNO3 to mols. mol = grams/molar mass = ? Using the coefficients in the balanced equation, convert mols KNO3 (what you have) to mols of what you want (mols O2). Then convert that to volume using PV = nRT. ...
July 28, 2015

chemistry
PV = nRT and solve for V in L.
July 28, 2015

chemistry
I would use (P1/T1) = (P2/T2), substitute and solve for T2. P1 = 1.248 atm T1 = 273 + 24.8 = ? P2 = 2.410 atm T2 = ? We don't need to worry about V because that doesn't change.
July 28, 2015

chemistry
No expressions given. But that's just a little algebra. I'll be glad to check you work.
July 28, 2015

chemistry
0.731 atm x (760 mm/1 atm) = ? Note how the atm unit cancels (the unit you don't want) so the answer comes out in mm (the unit you want to keep).
July 28, 2015

chemistry
The general gas law of PV = nRT can be modified to P*molar mass = density*RT. You can also work it the long way. PV = nRT and solve for n to find mols. Use 1L for volume. Then n = grams/molar mass. You know n and molar mass, solve for grams and that will be g/L since you used ...
July 28, 2015

chemistry
(P1V1/T1) = (P2V2/T2) T must be in kelvin.
July 28, 2015

Chemistry
(V1/T1) = (V2/T2) Remember T must be in kelvin.
July 28, 2015

Chemistry
The easy way to do this is to recognize that volume is proportional to mols of gas at the same T and P or (n1/v1) = (n2/v2) but an equally easy, but more work is to assume some value for T (any convenient numbers will work) and use PV = nRT, substitute the numbers and solve ...
July 28, 2015

Chemistry
Correct. Good work.
July 28, 2015

Chemistry
Do you know that STP stands for standard temperature and pressure. Standard T is 273 K and standard pressure is 1 atmosphere. Use (P1V2/T1) = (P2V2/T2) Don't forget to change degrees C to kelvin. Post your work if you run into trouble.
July 28, 2015

Chemistry
See your previous posts. Same formula, different numbers and different unknown.
July 28, 2015

Chemistry
See your water post just before this. Same formula, different numbers. Post your work if you get stuck or don't understand something.
July 28, 2015

Chemistry
No. What did you multiply? mass H2O = 550 g. specific heat H2O = 4.184 J/g*C Tfinal = 18 C Tinitial = 12 C
July 28, 2015

Chemistry
q = joules needed = mass H2O x specific heat H2O x (Tfinal-Tinitial)
July 28, 2015

chemistry
Your first post was answered. You need to look for the answer before posting a duplicate.
July 28, 2015

science
The water will float on the unknown liquid.
July 28, 2015

organic chemistry
I don't understand the problem. There is a cis-2-pentene and a trans-2 pentene. If the H atoms are on the same side it is cis and if they are on the opposite sides trans. Read about it here. https://en.wikipedia.org/wiki/Pentene
July 28, 2015

science
https://www.google.com/search?q=isa+relationshii&ie=utf-8&oe=utf-8
July 28, 2015

Nat Sci
I think you are right. Tectonic plates are the actual plates themselves while plate tectonics is the science (or the name of the science) of the process.
July 27, 2015

science
I agree with San.
July 27, 2015

Chemistry
You really don't know from the way the problem is stated; however, I assume the problem means "if the exact amount of reagents are mixed to produce the 2.89 g Ag2C4O4 and neither reagent is left". 2AgNO3 + Na2CrO4 ==> Ag2CrO4 + 2NaNO3. mols Ag2CrO4 = grams/...
July 27, 2015

chemistry
You want how many mols? That's M x L = mols. Then mols = grams/molar mass. YOu know mols and molar mass, solve for grams.
July 27, 2015

science
http://www.physics.org/article-questions.asp?id=65
July 27, 2015

Chemestry
1. Ca has a oxidation state of +2 on the left and zero on the right. Na is zero on the left and +1 on the right. Oxidation is the loss of electrons; reduction is the gain of electrons. Which lost and which gained and you have the answer. 2. What's your problem with this ...
July 27, 2015

chemistry
H2SO4 + 2NaOH ==> 2H2O + Na2SO4 mols 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 mols ad M, solve for L. Convert to cm^3 if needed.
July 27, 2015

m.e.i.pampore
The titration of a weak acid and strong base gives a pH at the equivalence point of between 8 and 10. The k1 for oxalic acid is fairly strong but hard to separate from k2. So you want an indicator that will change about 8-10. Phenolphthalein is suitable for that.
July 27, 2015

chemistry
How many mols is 3.50 g KI? That's mols = grams/molar mass = 3.5/approx 366 = approx 0.021 mols. You want to dilute the 5.95 to what volume? The new concentration of the 5.95M solution will be 5.95 x (0.047/y) = ? where y is the volume to which it is diluted but you don&#...
July 26, 2015

organic chemistry
http://chemwiki.ucdavis.edu/Theoretical_Chemistry/Chemical_Bonding/Valence_Bond_Theory/Resonance/Delocalization_of_Electrons
July 26, 2015

Chemistry
Some sites to choose from. Read, read, read. https://www.google.com/search?q=errors+in+colorimetry&ie=utf-8&oe=utf-8
July 26, 2015

Chemistry
mols Mn = grams/atomic mass mols C = grams/atomic mass Now find the ratio to each other with the smallest being 1.00. The easy way to do that is to divide the smaller number by itself (which makes it 1.00), the divide the other number by the same small number. Round to whole ...
July 25, 2015

Chemistry
mols NaOH = grams/molar mass = ? Then M = molarity = mols/L solution. You know mols and L, solve for M. That will be the OH^- since NaOH is a strong electrolyte. Convert to H^+ (H3O^+) with (H^+)(OH^-) = Kw = 1E-14 You know Kw and OH, solve for H..
July 25, 2015

informatic
Do you want a flow chart or a conversion chart?
July 25, 2015

chemistry
L is liters (or litres), not lt. 1 mole of a gas occupies 22.4 L at STP. So how many moles do you have? That's 5.8 L x (1 mol/22.4 L) = approx 0.25 but you need a more accurate answer than that. Then mols = grams/molar mass. You have mols and grams, solve for molar mass.
July 25, 2015

org chem
One reason is that glycerol boils close to 300 C and that is much higher than water. Boiling points would be much hard to obtain if they were above 100 and water was used. Oil is a good alternative for both melting and boiling point determinations.
July 25, 2015

Chem
q1 = heat needed to heat ice at -24 to zero C. q1 = mass ice x specific heat ice x (Tfinal-Tinitial) where Tf is zero and Ti is -24 q2 = heat needed to change solid ice at zero to liquid water at zero. q2 = mass ice x heat fusion. q3 = heat needed to heat water at zero to ...
July 24, 2015

chemistry
5.469 g = mass MgSO4 + xH2O -2.671 g = mass MgSO4 -------------- 2.798 g = mass H2O mols MgSO4 = 2.671/molar mass = ? mols H2O = 2.798/molar mass H2O = ? Now find the ratio for 1 mol MgSO4. The easy way to do that is to divide mols MgSO4 by itself (which automatically gives ...
July 23, 2015

chem 101
2NaOH + H2SO4 ==> Na2SO4 + 2H2O mols H2SO4 = M x L = ? Using the coefficients in the balanced equation, convert mols H2SO4 to mols NaOH. That's mols H2SO4 x (2 mols NaOH/1 ml H2SO4) = ? Then M NaOH = mols NaOH/L NaOH. YOu know M NaOH and mols NaOH, solve for L NaOH and ...
July 23, 2015

science: chemistry
HC2H3O2 = HAc moles HAc = M x L = 2.6 x 1 = 2.6 Let x = mols OH to be added. ..........HAc + OH^- --> Ac^- + H2O I.........2.6....0.......0.......0 add..............x............... C.........-x....-x.......x.......x E.........2.6-x..0.......x.......x I don't know what ...
July 23, 2015

science: chemistry
Convert 47.4 g C2H4NH3Cl to mols. mols = grams/molar mass = ?. Since that is in 1 L solution, that will be the molarity. This is the acid. You have 0.68 M solution of C2H4NH2 which is the base. Substitute into the Henderson-Hasselbalch equation, and solve for pH.
July 23, 2015

chemistry
I'm inclined to think gravimetric analysis would be better. Six grams is measured easily and accurately as is 100 mL. In most cases colorimetric analysis works best for dilute solutions; therefore, any small error in measurement would be magnified when converted to the ...
July 23, 2015

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