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April 16, 2014

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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chemistry
Hg2Cl2 = Hg + HgCl2 Please help me write the two half equations for this.
Monday, March 31, 2014 at 2:27am

Chemistry
As a technician in a large pharmaceutical research firm, you need to produce 100.mL of 1.00 M a phosphate buffer solution of pH = 7.45. The pKa of H2PO4− is 7.21. You have 2.00 L of 1.00 M KH2PO4 solution and 1.50 L of 1.00 M K2HPO4 solution, as well as a carboy of pure ...
Monday, March 31, 2014 at 1:45am

chemistry
You can google "table ionization potentials".
Monday, March 31, 2014 at 12:15am

chemistry
no thing given rather then this information and this is exam question how i can look for ionization energy?
Sunday, March 30, 2014 at 10:48pm

Chemistry
Watch the units. dGo part in kJ and +RTlnK part in J
Sunday, March 30, 2014 at 10:26pm

Chemistry
delta G rxn = dGo + RTlnQ where Q = (ADP)(HPO4^2-)/(ATP)
Sunday, March 30, 2014 at 10:24pm

chemistry
I would look at the ionization potential for each of the elements. The largest ionization potential is the one with the greatest attraction.
Sunday, March 30, 2014 at 10:22pm

chemistry
List the following in order of increasing force of attraction 1. an electron in the outer shell of carbon atom (in the ground state level) 1.1*10^(-10)m a part from nucleus. 2.an electron in the outer shell of oxegen atom (in the ground state level) 9.0*10^(-11)m a part from ...
Sunday, March 30, 2014 at 10:14pm

Chemistry
0.19M
Sunday, March 30, 2014 at 10:09pm

Chemistry
A critical reaction in the production of energy to do work or drive chemical reactions in biological systems is the hydrolysis of adenosine triphosphate, ATP, to adenosine diphosphate, ADP, as described by ATP(aq)+H20(l)-->ADP(aq)+HPO4^2-(aq) for which Delta G°rxn = &#...
Sunday, March 30, 2014 at 9:08pm

Chemistry
dG = -RTlnK. Solve for K. Then .......A + B ==> C I..0.30.0.0.40...0 C....-x....-x....x E..0.30-x..0.40-x..x Substitute the E line into Keq expression and solve for x, then evaluate concn A and B. Don't forget to use dG in J/mol and not kJ/mol
Sunday, March 30, 2014 at 8:50pm

Chemistry
A reaction A(aq)+B(aq)<-->C(aq) has a standard free-energy change of –3.35 kJ/mol at 25 °C. What are the concentrations of A, B, and C at equilibrium if, at the beginning of the reaction, their concentrations are 0.30 M, 0.40 M, and 0 M, respectively?
Sunday, March 30, 2014 at 8:04pm

Chemistry
Is this part of a problem and there is more to post? It appears to me you are have delta S vap and that x 7.40 will do it. But I may be confusing it with something else. If you have more to the problem please post it.
Sunday, March 30, 2014 at 7:18pm

chemistry
A complete combustion occurs when there is sufficient oxygen to react completely with the other material; i.e.., when the material being oxidized is the limiting reagent. An incomplete combustion occurs when there is insufficient oxygen to burn the other material completely; i...
Sunday, March 30, 2014 at 7:13pm

chemistry
N2 + 3H2 ==> 2NH3 delta E = q + w I would look up delta Hof. Then dHrxn = (n*dHoproducts) - (n*dHoreactants) and that will give you q. W is -p*delta V. Use PV = nRT. You know n, R, P, and T; solve for V at the end. Knowing mols formed you can calculate mols N2 and H2 ...
Sunday, March 30, 2014 at 7:09pm

chemistry
ssdsd
Sunday, March 30, 2014 at 6:40pm

chemistry
What is the change in the internal energy of the system when 1.243 mol of NH 3(g) is formed from N 2(g) and H 2(g) at 25 degrees C and 1.0 atm?
Sunday, March 30, 2014 at 6:33pm

chemistry
what is a complete and incomplete combustion reaction ??
Sunday, March 30, 2014 at 5:47pm

Chemistry
Determine the entropy change when 7.40 mol of HCl(l) boils at atmospheric pressure. I already have the delta Sfus(12.5 J/Kmol) and delta Svap(93.2 J/Kmol), I just cant seem to figure out the last part.
Sunday, March 30, 2014 at 5:41pm

chemistry
The answer with 3 sig figs and units is 43.6 g
Sunday, March 30, 2014 at 1:58am

Chemistry
gdh
Sunday, March 30, 2014 at 1:06am

Chemistry
I tried to find the response I made to your earlier question but I can't find it. At any rate, it doesn't matter what is used to standardize the NaOH. What is important is how many of the H atoms of the H2CO3 formed you titrate. That depends upon what kind of indicator...
Saturday, March 29, 2014 at 10:13pm

Chemistry
How does dissolved CO2 in distilled water affect the accuracy of the determination of a NaOH solution's concentration? How is the term acid anhydride applied here? I know you had answered this already, but what if KHP is used to titrate the NaOH. In this experiment KHP was...
Saturday, March 29, 2014 at 9:38pm

Chemistry
This is a heat problem, not a chemical problem so it really makes no difference at all about the identity of the acid or base. q = mass fluid x specific heat fluid x (Tfinjal-Tinitial) q is what you solve for. mass = 195 mL = 195 g with since density is 1.00 g/mL. specific ...
Saturday, March 29, 2014 at 9:07pm

Chemistry - Solubility
Mg(OH)2 ==> Mg^2+ + 2OH^- Ksp = (Mg^2+)(OH^-)^2 When NH3 is added to the solution of MgCl2 (which is quite soluble) the NH3 reacts with the H2O to form NH4^+ + OH^-. That increases the OH^- enough to form a Mg(OH)2 ppt because Ksp for Mg(OH)2 is exceeded. (SO YOU SHOULD ...
Saturday, March 29, 2014 at 9:02pm

Chemistry
I am thrown off by this question because they dont give a molecule to work with. Also i don't know how i would work the acid... help! A 195 mL solution of a dilute acid is added to 102 mL of a base solution in a coffee-cup calorimeter. The temperature of the solution ...
Saturday, March 29, 2014 at 8:47pm

Chemistry - Solubility
1.a) What did you observe upon the addition of NH3 (aq) to the magnesium chloride solution? Explain using relevant chemical reactions. I observed a colorless liquid. (Not sure how to explain) b) What happens when NH4Cl was added? Explain observation with respect to the ...
Saturday, March 29, 2014 at 8:40pm

Chemistry
Thank you!
Saturday, March 29, 2014 at 8:32pm

Chemistry - Solubility Product
See your other post.
Saturday, March 29, 2014 at 6:52pm

Chemistry
You had a saturated solution of PbCl2 which means that (Pb^+)(Cl^-)^2 was just equal to Ksp. When you added dilute HCl, you increased the (Cl^-) [the common ion effect] and this DECREASED the solubility of PbCl2; therefore, some of the PbCl2 pptd and that's what you saw. ...
Saturday, March 29, 2014 at 6:52pm

Chemistry - Solubility Product
What did you observe after the addition of dilute HCl to the saturated lead chloride solution? Explain observations using relevant chemical reaction. I observed that a white precipitate was formed. Not sure how to explain why it formed
Saturday, March 29, 2014 at 6:46pm

Chemistry
What did you observe after the addition of dilute HCl to the saturated lead chloride solution? Explain observations using relevant chemical reaction. I observed that a white precipitate was formed. Not sure how to explain why it formed
Saturday, March 29, 2014 at 6:44pm

chemistry
I'm sorry. That's a bad habit of mine; i.e., making a comment but not including the url.Here is is. http://en.wikipedia.org/wiki/N-Bromosucc​inimide
Saturday, March 29, 2014 at 4:49pm

chemistry
the right answer is A. the unknown solution has the lower concentration ...
Saturday, March 29, 2014 at 3:51pm

chemistry
can you give me the website?
Saturday, March 29, 2014 at 3:38pm

chemistry
We can't draw structure on this forum but here is a site that give the structural formula. You can add the dots and needed.
Saturday, March 29, 2014 at 3:20pm

chemistry
HCN. H to C is sp C-N is sp. Then twp p-p bonds form the other two to make C-triple bond-N
Saturday, March 29, 2014 at 3:17pm

Chemistry
KE = (1/2)*m*v^2 KE in joules = (1/2)*1533 kg x v^2 Convert 90.6 km/hr into m/s and substitute into the above formula, Solve for KE. I get 25.17 m/s for the conversion but you should confirm that. .
Saturday, March 29, 2014 at 3:10pm

chemistry
what is the hybridization of each atom for hydrocyanic acid?
Saturday, March 29, 2014 at 3:09pm

chemistry
3Ba^2+ + 2PO4^3- ==> Ba3(PO4)2(s) Convert mols each to mols product. 0.5 mol BaCl2 x (1 mol product/3 Ba^2+) = approx0.167 mols Ba3(PO4)2 produced. 0.2 mol Na3PO4 x (1 mol product/2 mol PO4^3-) = 0.1 mol Ba3(PO3)2 produced. In limiting reagent problems the smaller number ...
Saturday, March 29, 2014 at 3:03pm

Chemistry
You can find other answers to the CO2 question and some analytical chemists don't agree with this but I think it may or may not make a difference. When CO2 reacts with NaOH it forms Na2CO3. CO2 + 2NaOH ==> Na2CO3 + H2O. For every mole CO2 added we form 1 mol Na2CO3 and ...
Saturday, March 29, 2014 at 2:54pm

chemistry
what is the lewis structure for N-bromosuccinimide?
Saturday, March 29, 2014 at 2:44pm

chemistry
I expect it's dipole-dipole.
Saturday, March 29, 2014 at 2:28pm

chemistry
What are strongest intermolecular force in hydrogen iodide ?
Saturday, March 29, 2014 at 1:59pm

Chemistry
In this experiment NaOH is standardized to titrate it with vinegar so thtat the percent by mass of the acetic acid can be determined. How does dissolved CO2 in distilled water affect the accuracy of the determination of a NaOH solution's concentration? How is the term acid...
Saturday, March 29, 2014 at 12:36pm

Chemistry
In this experiment NaOH is standardized to find out the percent by mass of the acetic acid in a sample of vinegar. A student had not allowed the NaOH pellets to dissolve completely before standardizing it with KHP, but when the student refilled the buret with NaOH to titrate ...
Saturday, March 29, 2014 at 12:32pm

chemistry
if .5 mole of baCl2 is mixed with .2 mole of Na3Po4.Then maximum number of mole of Ba3(PO4)2 is
Saturday, March 29, 2014 at 11:48am

Chemistry
A 1533 kg car is traveling down the road at 90.6 km/h. While traveling at this rate of speed, what is the kinetic energy of this vehicle in kilojoules?
Saturday, March 29, 2014 at 9:18am

chemistry
567.99
Saturday, March 29, 2014 at 4:47am

Chemistry Help Please!!!
1) KaKb = Kw = 1E-14 2) I have no idea what NaC2 is.I suspect you were trying to write NaC2H3O2. I would expect the pH of a 0.1M solution of NaC2H3O2 to be the same as a 0.1M solution of KC2H3O2. The pH is determined by the hydrolysis of the C2H3O2^- ion and that would be the ...
Saturday, March 29, 2014 at 1:43am

Chemistry Help Please!!!
What is the greatest source of error for the hydrolysis of salts and pH of buffer solutions lab?How would you minimize this source of error?
Saturday, March 29, 2014 at 1:32am

Chemistry Help Please!!!
1) using kb for NH3 calculate ka for NH4+ ion. Compare this value with that calculated from your measured ph's? 2) how should the pH of a 0.1M solution of NaC2 at H3O2 compare with that of a 0.1 M solution of KC2H3O2? Explain briefly? THANK YOU!
Saturday, March 29, 2014 at 1:29am

chemistry
There is a simple dilution formula you can use for all of these. c1v1 = c2v2 c = concentration v = volume 1M x ?mL = 0.1M x 100 mL ?mL = (0.1M x 100 mL)/1M = 10 mL
Saturday, March 29, 2014 at 12:33am

chemistry
how many mL of 1M HCL is used to make: 100mL of 0.1M hcl 250Ml OF 0.5M hcl 10Ml OF 0.01m hcl
Saturday, March 29, 2014 at 12:21am

Chemistry
I think the % acetic acid will be too high. Standardization step: mols KHP = grams KHP/molar mass KHP mols NaOH = mols KHP M NaOH = mols NaOH/L NaOH Titration vinegar step: mols NaOH titrant = M x L mols acetic acid = mols NaOH g acetic acid = mols acetic acid x molar mass % ...
Friday, March 28, 2014 at 10:50pm

Chemistry
Titration was used to determine the molarity of acetic acid in vinegar. A primary standard solution of KHP was used to standardize the NaOH. 1. When performing this experiment, impure KHP was used to standardize the NaOH solution. If the impurity is neither acidic or basic, ...
Friday, March 28, 2014 at 10:32pm

Chemistry needs help
Indicate your specific subject in the "School Subject" box, so those with expertise in the area will respond to the question.
Friday, March 28, 2014 at 4:41pm

chemistry
I don't think so but you may find something here. https://cs.uwaterloo.ca/journals/JIS/cay​ley.html
Friday, March 28, 2014 at 3:23pm

chemistry
This is a little confusing to me; i.e., #1 will make a buffer but not a very good one. #4 will have a pH = 7.0 but not good buffering characteristics. I need to know what you don't understand and what have you answered (and why?)
Friday, March 28, 2014 at 3:14pm

CHEMISTRY
First part. You have subtracted correctly and MASS of the water in the flask is 248.4 grams. Then since mass = volume x density you can rearrange that to volume = mass/density mass = 248.4g and density of the H2O is 1 g/mL (from the problem), then 248.4g/1 g/mL so volume is ...
Friday, March 28, 2014 at 3:05pm

Chemistry
Did you read my response to your earlier post with this same question? If not you should go back to read it. If so, then please go through and explain, in detail, exactly what you don't understand about my answers. If I answer this post I'll just rewrite what I've ...
Friday, March 28, 2014 at 2:54pm

chemistry
First determine the concn of HNO3 in the 19.0% stuff. 1.11 g/cc x 1000 cc x 0.19 x (1 mol/98 g) = estimated 2 mol/dm^3 Then use the dilution formula of c1v1 = c2v2 2*v = 2*3 Solve for v = approx 3 dm^3 Remember to recalculate all of the above.
Friday, March 28, 2014 at 2:46pm

chemistry
Select only the True statements about buffer systems. Select all that are True. 1. Starting with NH3(aq) and adding a small amount of HCl(aq) will make a buffered solution. 2. The blood buffer, among other things, is supported by carbonic acid and its conjugate base ...
Friday, March 28, 2014 at 2:45pm

Chemistry
Mg + H2SO4 ==> MgSO4 + H2 mols H2 = 9.5L/22.4L = 0.5 ESTIMATED so you should redo the calculation as well as all that follow for they are estimates also. 0.5 mol H2 means you started with 0.5 mol H2SO4 g H2SO4 = mols H2SO4 x molar mass H2SO4 = estimated 42 grams The ...
Friday, March 28, 2014 at 2:37pm

chemistry
mols = grams/molar mass
Friday, March 28, 2014 at 2:30pm

Chemistry
I don't know exactly how the experiment was conducted but I think 1 is right. For 2, however, I think the results must be either too high or too low (but see the note below). If too little liquid is placed in the flask that means that vapor cannot fill the flask so your ...
Friday, March 28, 2014 at 2:29pm

chemistry
Pleas does any one know how to calculate the number of isomers of an organic compound. Any formula pls
Friday, March 28, 2014 at 2:21pm

Chemistry
I got think I got the following questions almost figured, but I just want someone to make sure that I am correct. 1) The whole experiment involves using the ideal gas law to predict the molar mass of an unknown liquid. The formula is molar mass of liquid = gR(0.0821)T(...
Friday, March 28, 2014 at 1:42pm

chemistry
278.35g Ba3n2 to mole Ba3N2
Friday, March 28, 2014 at 1:19pm

logic and math
Calculate the truth value (f or V) a. Is it true that if (the Papaya is a fruit from the Caricaseas or the Pitahaya is the fruit of a plat from the Cactaseas) then (el Cohombro is a fruit of a plant from the family of the Cucurbitaceas or the Nisper is a fruit of a tree from ...
Friday, March 28, 2014 at 12:47pm

College Chemistry (DrBob222)
Excellent job! Thanks a lot
Friday, March 28, 2014 at 12:37pm

chemistry
Calculate the PH of 0.025moldm3 trioxonitrate(v) solution.
Friday, March 28, 2014 at 10:33am

Chemistry
excess magnesium is reacted with 45 grams of sulfuric acid. 9.5 liters of hydrogen gas are collected understand conditions of temperature and pressure. what is the percentage of hydrogen sulfate and of water in the acod solution?
Friday, March 28, 2014 at 7:43am

chemistry
2 Except for rubidium and caesium, all common cations are smaller than all common anions all common cations are larger than all common anions all common cations are of the same size with all common anions the cations are not avaliable
Friday, March 28, 2014 at 7:31am

chemistry
The density of 19.0% by mass of nitric acid, HNO3 is 1.11 g cm-3. Calculate the volume (dm3) of acid needed to prepare 2.00 dm3 of 3.00 mol dm-3 HNO3 solution. (FW HNO3 = 63 g/mol)
Friday, March 28, 2014 at 3:56am

Chemistry
Or calculate dHo and dSo at standard enthalpies of formation and entropies?
Friday, March 28, 2014 at 1:42am

Chemistry
Thank you DrBob22. :) But for #1, am I looking for dGo for H2(g)?
Friday, March 28, 2014 at 1:28am

Chemistry
I would really like to understand how to do these problems, because my exam is coming up in a few weeks. I still cannot comprehend how you can tell if a system is is positive or negative according to reaction. For #1, I presume it is E if it is spontaneous at all temperatures...
Friday, March 28, 2014 at 1:18am

CHEMISTRY
The mass of an erlenmeyer flask is 78.639g and the mass of the flask and water is 327.039. If the density of water is 1 g/ml then what is the true volume of the flask? so i had subtracted the mass of just the flask from the mass of the flask and the water and got 248.4. Would ...
Friday, March 28, 2014 at 1:01am

Chemistry
I work these LR problems the long way. CuCl + H2S --> Cu2S + 2HCl mols CuCl = grams/molar mass mols H2S = grams/molar mass Using the coefficients in the balanced equation, convert mols CuCl to mols Cu2S. Do the same for mols H2S to mols Cu2S. It is likely that the values ...
Thursday, March 27, 2014 at 10:37pm

Chemistry
copper(1) chloride reacts with hydrogen sulfide. if 9.90 grams of copper(1) chloride and 10.2 grams of hydrogen sulfide are reacted together, what is the limiting reactant?
Thursday, March 27, 2014 at 10:13pm

chemistry
MgF2 ==> Mg + F2 ......1.65kg..2.58 kg So you must have started with 1.65 + 2.58 = ? kg MgF2. MgF2 ==> Mg + F2 .......1.50kg..? I would use ratio/proportion on this. (1.65/1.50) = (2.58/x) Solve for x.
Thursday, March 27, 2014 at 9:40pm

chemistry
Upon decomposition, one sample of magnesium fluoride produced 1.65 kg{\rm kg} of magnesium and 2.58 kg{\rm kg} of fluorine. A second sample produced 1.50 kg{\rm kg} of magnesium. How much fluorine (in grams) did the second sample produce?
Thursday, March 27, 2014 at 9:20pm

Chemistry
I'm confused. You have an unknown base, you're titrating with HCl, and you're adding NaOH? Something strange in Denmark.
Thursday, March 27, 2014 at 8:57pm

Chemistry URGENT
Linda, I did this for you earlier, also. The only problem I see is that you made a typo in transcribing my answer. You wrote CO instead of CO2 and that's why it wouldn't balance for you.
Thursday, March 27, 2014 at 8:52pm

Chemistry URGENT
Linda, I did these for you earlier. You've just copied my work Is it that you want a second opinion?
Thursday, March 27, 2014 at 8:50pm

oops---Chemistry
What I stated as answer for #2 actually is B of #1.
Thursday, March 27, 2014 at 7:07pm

Chemistry
I think for #2 you are to use Keq expression with dG which is dG = -RTlnK. and go from there. So you know R, and T, K = p(H2)/p(H2O) substitute and solve for dG.
Thursday, March 27, 2014 at 7:05pm

Chemistry
Yes, for #1 use dGo = dHo - TdSo. That will give you dGo. Then if you assume dH = dHo and dS = dSo and use T = 500K.
Thursday, March 27, 2014 at 7:00pm

Chemistry URGENT
Oh, divide by 2 C6 H10 O5 + 6 O2 ---> 6CO2 + 5 H2O
Thursday, March 27, 2014 at 6:58pm

Chemistry
a.) How much energy is emitted in each alpha decay of plutonium-234 if 234Pu, 234.0433mu and 230U, 230.0338mu. b.) The half-life of plutonium-234 is 8.8 hrs. How much heat is released by the alpha decay of a 1 micro-gram sample of plutonium-234 in a 24-hour period? For part a...
Thursday, March 27, 2014 at 6:47pm

Chemistry
You're right for #3. dG = 0 at equilibrium.
Thursday, March 27, 2014 at 6:46pm

Chemistry
2. Consider the following reaction: C3H8(g) + 5O2(g) ---> 3CO2(g) + 4H2O(g) One would predict that A) ΔH is positive and ΔS is positive for the reaction. B) ΔH is negative and ΔS is negative for the reaction. C) ΔH is negative and ΔS is ...
Thursday, March 27, 2014 at 6:45pm

Chemistry URGENT
C6 H10 O5 + O2 ---> CO2 + H2O we need an even number of O atoms 2 C6 H10 O5 + x O2 ---> 12CO2 + 10 H2O now O balance 10 + 2x = 24 + 10 x = 12 2 C6 H10 O5 + 12 O2 ---> 12CO2 + 10 H2O
Thursday, March 27, 2014 at 6:41pm

Chemistry
1. The following reaction is spontaneous at all temperatures: CaC2(s) + 2H2O(l) ---> Ca(OH)2(s) + C2H2(g) Which of the following statements is true? A) ΔG is positive at all temperatures. B) ΔG is positive and ΔS is positive. C) ΔH is negative and Δ...
Thursday, March 27, 2014 at 6:40pm

Chemistry
The main radioisotope in a banana is potassium-40, a beta emitter with an activity of 242 Bq/g. An average medium banana has about 320 mg of potassium and the natural abundance of potassium-40 is .0117%. Calculate the value of the BED in a.) Gy b.) Sv Assume 5.02 nGy/Bq
Thursday, March 27, 2014 at 6:39pm

Chemistry URGENT
I see nothing wrong with them.
Thursday, March 27, 2014 at 6:35pm

Chemistry
2 * 7.9 = 15.8 mols C 15.8 * 12 g/mol = 189.6 grams of carbon
Thursday, March 27, 2014 at 6:33pm

Chemistry URGENT
Could someone let me know if I have balanced these equations correctly. balanced equation of the reaction of iron and oxygen to produce iron(ii)oxide. 2Fe + O2 = 2FeO Also if the balanced equation of the reaction of iron and oxygen to produce iron(iii)oxide. 4Fe+302 = 2Fe2O3 ...
Thursday, March 27, 2014 at 6:29pm

Chemistry URGENT
I need help balancing a equation for the combustion of cellulose in oxygen to produce carbon dioxide and water vapor. C6H10O5 = 6CO +5H2O I know this is not correct but I don't know what else to do to get this to balance. Thanking you in advance.
Thursday, March 27, 2014 at 6:22pm

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