Friday
April 18, 2014

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Post a New Question | Current Questions

chemistry
how many milliliters of .400M hydrogen Monobromide solution can be made from 50mL of 8M hydrogen monobromide solution?
Tuesday, April 8, 2014 at 4:03pm

Chemistry
eqn 1 CaF2 ==> Ca^2+ + 2F^- eqn 2 Ca^2+ + SO4^2- ==> CaSO4 ------------------------------- sum 1+2 CaF2 + SO4^2- ==> (F^-)^2 + CaSO4 since CaF2 and CaSO4 are solids we can cancel them since they are not involved in the Keq. You note that eqn 1 is Ksp for CaF2 and eqn ...
Tuesday, April 8, 2014 at 2:46pm

Chemistry
This is a long (but not particularly complicated) calculation to do on the web. Do you have a specific question that is troubling you?
Tuesday, April 8, 2014 at 2:33pm

Chemistry
From what I can read you don't have sufficient information here to calculate a LSI. pH alkalinity T etc.
Tuesday, April 8, 2014 at 2:32pm

chemistry
Are my answers correct? Identify each energy exchange as primarily heat or work and determine weather the sign of ΔE is positive or negative for the system. A. A rolling billiard ball collides with another billiard ball. The first ball (system) stops rolling after the ...
Tuesday, April 8, 2014 at 2:18pm

Chemistry
1 mol contains 6.02 E23 molecules.
Tuesday, April 8, 2014 at 2:12pm

Chemistry lab
You need to correct this post. 0.9 mM of what?
Tuesday, April 8, 2014 at 2:11pm

chemistry
1.28
Tuesday, April 8, 2014 at 12:55pm

Chemistry lab
I mixed 10 mL of 9mM KI with 5 mL of 0.9mM in a flask, and then added it to a beaker that contained 10 mL of 45 mM KBrO3, and 10 mL of 90mM HCl. This reaction took 61.60 seconds to complete. I think I need to find the change in concentration, but don't know how to do this...
Tuesday, April 8, 2014 at 12:43pm

Chemistry
From the solubility product constants for CaF2 (fluorite) and CaSO4 (anhydrite) determine the equilibrium constant for the reaction CaF2 + SO4 2- --> CaSO4 + 2F-
Tuesday, April 8, 2014 at 11:59am

Chemistry
What is the ionic strength, I, of a solution at 25C containing 0.002 mol/L of BaSO4 and 0.001 mol/L of BaCl2? What is the activity coefficient of Ba2+ in this solution?
Tuesday, April 8, 2014 at 11:57am

Chemistry
Consider a groundwater saturated with respect to PbSO4 (Ksp= 1.7*10^-8) mixing with a groundwater saturated with respect to CaSO4 (Ksp=10^-5). Assume a 50:50 mixture between the waters such as 500mL of each water mixing to form a 1.0L solution a. What is the saturation index (...
Tuesday, April 8, 2014 at 11:56am

Chemistry
How many moles are in 1.50 x 1023 molecules NH3? A. 2.49 x 10 -1 mol NH3 B. 2.49 x 101 mol NH3 C. 2.65 x 10 -1 mol NH3 D. 2.78 x 10 1 mol NH3
Tuesday, April 8, 2014 at 11:55am

chemistry
Are my answers correct? Identify each energy exchange as primarily heat or work and determine weather the sign of ΔE is positive or negative for the system. A. A rolling billiard ball collides with another billiard ball. The first ball (system) stops rolling after the ...
Tuesday, April 8, 2014 at 10:36am

Chemistry Help(Calorimetry)
rich china johnny ray
Tuesday, April 8, 2014 at 10:01am

Chemistry
This is for part 1. Mix 50.0 mL of 0.20 M sodium acetate with 10.0 mL of 1.0 M acetic acid and 40.0 mL deionized water.
Tuesday, April 8, 2014 at 9:55am

Chemistry
balance this: CuSO4>>CuO + SO3
Tuesday, April 8, 2014 at 9:55am

chemistry
yli
Tuesday, April 8, 2014 at 9:54am

Chemistry
Can someone please help me here? It's review for my test. Thanks! Calculate the expected pH of the buffer prepared in Part I of this lab. The Ka of acetic acid is 1.8 x 10-5 Calculate the expected pH when 10.0mL of 0.10M HCl is added to the buffer from question 3 Calculate...
Tuesday, April 8, 2014 at 9:54am

chemistry
.0290M
Tuesday, April 8, 2014 at 2:03am

Chemistry
I am not sure if I understand how to balance this correctly. I need to write a balanced equation for the decomposition of solid copper(ii) sulfate to form gaseous sulfur trioxide and solid copper (ii) oxide. 2CuSO7 = CuSO4 + SO3 + CuO
Tuesday, April 8, 2014 at 1:33am

Chemistry Help Please!!!
The equation you want is (1/2^t/4)= x amount remaining which in this case is (1/2^30/4) = (1/2^7.5)= x Solve that equation for the amount remaining after 30 days. Using that equation you should be able to do the others. For example c is [(1/2^(t/4)] = 1 and solve for t.
Tuesday, April 8, 2014 at 1:01am

Chemistry Help Please!!!
A radioactive substance has a half-life of 4 days. Suppose we have 800 mg of this substance. a) Find the equation of the mass remaining after t days. Use the exact value for k not a decimal approximation. b) Rounding your answer to the nearest tenth of a mg, find the mass ...
Monday, April 7, 2014 at 11:26pm

Chemistry
If p is same and T is same then mols is proportional to volume. If you have 1/3 the volume you must have 1/3 the mols.
Monday, April 7, 2014 at 10:51pm

Chemistry
There are two containers filled with gases. In both containers, gases are at the same temperature and presssure. The first container is 3 L and contains 0.9 moles of gas. The second container is 1 L. How many moles of gas are there in the second container?
Monday, April 7, 2014 at 10:42pm

Chemistry
ptotal = pN2 + pO2
Monday, April 7, 2014 at 10:42pm

Chemistry
a gaseous mixture of nitrogen and oxygen has a total pressure of 770 torr. the partial pressure of nitrogen is 700 torr. what is the partial pressure of oxygen?
Monday, April 7, 2014 at 10:40pm

chemistry
For the freon see your other post. For this other problem the pressure has changed. p1/t1 = p1/t2 t1 and t2 must be in kelvin.
Monday, April 7, 2014 at 10:35pm

Chemistry
First note the correct spelling of celsius. Calculate n = number of mols from PV = nRT. Then n = grams/molar mass. You have n and grams, solve for molar mass. Don't forget to convert mm Hg to atm and T to kelvin.
Monday, April 7, 2014 at 10:32pm

Chemistry
calculate the molar weight of Freon-II, of 8.29 liters of its vapor at 200 degrees celcius and 790 mm Hg has a mass of 30.5 g.
Monday, April 7, 2014 at 10:28pm

chemistry
A gas sealed vial originally at 0.6 atm and 300 K, was heated at 450 K. What other property of the gas has changed? What is the value of this property after heating?
Monday, April 7, 2014 at 10:25pm

chemistry
calculate the molar weight of Freon-II, of 8.29 liters of its vapor at 200 degrees celcius and 790 mm Hg has a mass of 30.5 g.?
Monday, April 7, 2014 at 10:20pm

Chemistry
How many mols do you need? That's mols = M x L = 0.48 x 0.1235 L = ? Then M = mols/L soln. Substitute. Solve. You know M = 5.00 and you know mols from above. Solve for L and convert to mL.
Monday, April 7, 2014 at 10:18pm

Chemistry
I assume we are to ignore the calorimeter constant. [mass metal x specific heat metal x (Tfinal-Tinitial)] + [mass H2O x secific heat H2O x (Tfinal-Tinitial)] = 0. Substitute and solve for s.h. metal.
Monday, April 7, 2014 at 10:14pm

Chemistry
A piece of metal weighing 5.10g at a temperature of 48.6 degree Celsius was placed in a calorimeter in 20.00 mL of water at 22.1 degree Celsius. The final equilibrium temperature was found to be 29.2 degree celsius. What is the specific heat of the metal?
Monday, April 7, 2014 at 9:55pm

Chemistry
5.2mL
Monday, April 7, 2014 at 9:48pm

Chemistry
How many milliliters of a 5.0 M H2SO4 stock solution would you need to prepare 123.5 mL of 0.48 M H2SO4?
Monday, April 7, 2014 at 9:38pm

chemistry
.75 * .5 = .375 mols of Na2CO3 2 HCl + Na2CO3 --> 2 NaCl + H2O +CO2 so we need .375 * 2 = .75 mols of HCl .75 * 1.25 = .9375 Liters
Monday, April 7, 2014 at 8:47pm

chemistry
Those are conversion factors that I posted. Let's work with the first one. A conversion factor converts anything you have into anything you want (if you have the right factor and use it correctly). So the factor is 1 atm/101.325 kPa and of course it can also be 101.325 kPa...
Monday, April 7, 2014 at 8:33pm

chemistry
What volume of 1.25M HCl in liters is needed to react completely (with nothing left over) with 0.750L of 0.500M Na2CO3?
Monday, April 7, 2014 at 8:29pm

Chemistry
Yes, but Mols of H2SO4 in ONE LITER 3 M means 3 mols in a liter 9 M means 9 mols in a Liter
Monday, April 7, 2014 at 8:17pm

Chemistry
Could someone please let me know if I have the answer to the following question correct? If my answer is incorrect could you please help me answer this question. what is the difference between 3M and 9M of sulfuric acid? I think the difference is that there are 3 moles of ...
Monday, April 7, 2014 at 8:15pm

chemistry
313
Monday, April 7, 2014 at 7:01pm

chemistry
How do I actually do this? I am trying to show my daughter how to do it and have no clue.
Monday, April 7, 2014 at 6:59pm

chemistry
1 atm = 101.325 kPa. 1 atm = 14.7 psi
Monday, April 7, 2014 at 6:49pm

Chemistry
P1V1 = P2V2 Substitute and solve for the one unknown. Change atm to mm Hg. 1 atm = 760 mm Hg.
Monday, April 7, 2014 at 6:48pm

chemistry
Convert the following pressures to pressures in atmospheres. a. 151.98 kPa b. 45.6 psi
Monday, April 7, 2014 at 6:33pm

Chemistry
A gas has a pressure of 4.62 atm when its volume is 2.33 L. If the temperature remains constant, what will the pressure be when the volume is changed to 1.03 L? Express the final pressure in mm Hg.
Monday, April 7, 2014 at 6:31pm

Chemistry
-456
Monday, April 7, 2014 at 5:44pm

Chemistry
first dilution: you diluted it to 10/19 of .1M, so it is 10/190 M. Then you diluted it 10/100 of its concentration, new concentration 10/1900 M the statement <The student diluted the sample as above 1 time(s).>> makes no sense to me, it it means my first paragraph, ...
Monday, April 7, 2014 at 5:32pm

Chemistry
10 mL of 0.1 HCl was added to 9mL of water. 10 mL of that solution was added to another 90 mL of water. The student diluted the sample as above 1 time(s). What is the pH of the solution?
Monday, April 7, 2014 at 5:13pm

Chemistry
You blow me????
Monday, April 7, 2014 at 3:46pm

Chemistry
Here is a copy of the activity series of metals. Any metal ion below Ag should oxidized Ag metal to Ag +1 ion. So Pt and Au ions should do it https://www.google.com/search?q=activity​+series+metals&client=firefox-a&hs=dwv&r​ls=org.mozilla:en-US:official&channel=sb...
Monday, April 7, 2014 at 3:25pm

chemistry
Three equations and three unknowns but the way they are set up makes it as if it were two equations and two unknowns. Let X = mass NaX and Y = mass NaI and Z = mass NaNO3 (mm stands for molar mass) --------------------------- eqn 1 is Z + Y + Z = 0.8612g eqn 2 is mass AgBr ...
Monday, April 7, 2014 at 3:07pm

chemistry
millimols C2H5NH2 = mL x M = 25 x 0.5 = 12.5 mmols HCl = 5 mL x 0.5M = 2.5 HCl. .......C2H5NH2 + HCl --> C2H5NH3^+ + Cl^- I.......12.5.......0.........0......0 added............2.5................ C.......-2.5....-2.5........+2.5....2.5 E.......10.0......0..........2.5....2...
Monday, April 7, 2014 at 2:14pm

chemistry
A solution of 25mL of 0.5M c2h5nh2 is titrated with hydrochloric acid solution. During titration 5mL of .5M hcl is added dropwise. As volumes are additive. Calculate the pH of the resulting solution
Monday, April 7, 2014 at 12:03pm

chemistry
heat gained by rod + heat lost by H2O = 0 [mass Fe x specific heat Fe x (Tfinal-Tinitial)] + [mass H2O x specific heat H2O x (Tfinal-Tinitial)] = 0 32.2*0.450*(58.6-22.3)+m*4.179*(58.6-63.​9)=0 525.987=m*22.148 m=23.748 grams
Monday, April 7, 2014 at 11:21am

chemistry
heat gained by rod + heat lost by H2O = 0 [mass Fe x specific heat Fe x (Tfinal-Tinitial)] + [mass H2O x specific heat H2O x (Tfinal-Tinitial)] = 0 32.2*0.450*(58.4-22.8)+m*4.179*(58.4-63.​7)=0 515.844=m*22.148 m=23.3 grams
Monday, April 7, 2014 at 11:19am

chemistry
THAT DIDNT WORK EITHER
Monday, April 7, 2014 at 10:40am

chemistry
A 0.8612g sample of a mixture consisting of NaBr,NaI and NaNO3 was analysed by adding AgNO3 to precipitate the Br^- and I^-,yielding 1.0186g mixture of AgBr and AgI.The precipitate was then heated in a stream of Cl2, converting it to 0.7125g of AgCl. Calculate the %w/w NaNO3 ...
Monday, April 7, 2014 at 8:15am

chemistry
a solution formed by mixing 50ml of 10.0 M NaX with 50ml of 2.0x10^3M CuNO3.Assume that Cu(l) forms complexions with X asn follows Cu^+ + X^- = CuX K1=1x 10^2 CuX + X^- = CuX2^- K2=1 x10^4 CuX2^- + X^- =CuX3^2- K3= 1x10^3 with overall reaction Cu^+ +3X^- = CuX3^2- K=1X 10^9 ...
Monday, April 7, 2014 at 7:16am

chemistry
I would expect the HCL to be diluted with water, so the complete reaction would be... Mg+ water>hydrogen gas + magnesium hydroxide in addidtion to the reaction you wrote. I expect the acid reaction to be faster, so as it is diluted, you notice the rate decreases. However, ...
Monday, April 7, 2014 at 7:14am

chemistry
if I have the reaction Magnesium + Hydrochloric Acid -> Magnesium Chloride + Hydrogen Gas And I have to 'investigate the effect of the concentration of the acid on the volume of hydrogen gas produced in the above reaction', what would be expected to happen?
Monday, April 7, 2014 at 7:09am

Chemistry
(mass ice x heat fusion) + [mass ice x specific heat water x (Tfinal-Tinitial)] [mass H2O x specific heat H2O x (Tfinal-Tionitial)] = 0 Substitute and solve for mass ice. Tfinal is 4, Tinitial is 26, mass H2O (that's the 26 C H2O) is 355. Massice is the only unknown.
Monday, April 7, 2014 at 1:49am

Chemistry
Thanks for the clarification! So besides Mercury, is there any metal cation that can oxidize silver metal to aqueous silver cation?
Monday, April 7, 2014 at 1:49am

Chemistry
For a voltaic cell that's made with zinc and copper {reaction equation: Zn(s) + Cu2+(aq) ---> Cu(s) + Zn2+(aq)}, if the concentration of zinc nitrate increases, would the cell voltage decrease, or would it increase? Thanks!
Monday, April 7, 2014 at 1:47am

Chemistry
Use the Clausius-Clapeyron equation. Don't forget to substitute dHvap in J/mol.
Monday, April 7, 2014 at 1:46am

Chemistry
Ag(s) ==> Ag^+ + e Eo = -0.799 Hg^2+ + 2e ==> Hg..Eo = +0.789 ------------------------ 2Ag(s) + Hg2^2+ => 2Ag^+ + Hg E = -0.01 If it would oxidize it yes, that would be the reaction; however, you can see that the Eo value is -0.01 so it isn't spontaneous. K for ...
Monday, April 7, 2014 at 1:45am

organic chemistry
For proton NMR spectra, does a peak at 0 ppm indicate anything significant or is it likely to be a signal arising from a solvent?
Monday, April 7, 2014 at 1:25am

Chemistry
Can the mercury cation (Hg2+) oxidize silver metal to aqueous silver cation? If so, would the reaction equation be as follows: 2 Ag(s) + Hg2+(aq) ---> Hg(l) + 2 Ag+(aq) Thank you!
Monday, April 7, 2014 at 1:21am

Chemistry
LOL @ WHAT. ARE YOU IN MS. PETERS? I HATE THAT CLASS SO MUCH
Monday, April 7, 2014 at 12:16am

Chemistry
Benzene has a heat of vaporization of 30.72kJ/mol and a normal boiling point of 80.1 ∘C. At what temperature does benzene boil when the external pressure is 480torr ?
Monday, April 7, 2014 at 12:02am

Chemistry
How much ice (in grams) with the temperature of 0∘C would have to melt to lower the temperature of 355mL of water from 26∘C to 4∘C? (Assume the density of water is 1.0 g/mL.)
Monday, April 7, 2014 at 12:00am

Chemistry
What are the signs of dH, dS, and dG for the following and please explain why? Also what does it mean by sublimation, and molten? 1. CO2(s) --> CO2(g) (Dry ice subliming) dH = ? dS = ? dG = ? 2. The electrolysis of molten NaCl(l). dH = ? dS = ? dG = ?
Sunday, April 6, 2014 at 10:56pm

chemistry
It's in the last sentence.
Sunday, April 6, 2014 at 10:46pm

chemistry
nevermind. thank you!
Sunday, April 6, 2014 at 10:42pm

chemistry
i understand how to solve this but i do not know the calorimeter constant
Sunday, April 6, 2014 at 10:42pm

Chemistry
Now you need dHof fpr H2O gas. dHrxn = (n*dH products) - (n*dH reactants)
Sunday, April 6, 2014 at 10:39pm

chemistry
q(v) = Ccal in kJ/C x delta T That gives you q = dE in kJ for 0.451g That x molar mass gives dE in kJ/mol.
Sunday, April 6, 2014 at 10:36pm

College Chemistry (DrBob222)
Ahhhh, now it's all clear! Thank you!
Sunday, April 6, 2014 at 10:35pm

Chemistry
Propane (C3H8) burns according to the following balanced equation: C3H8(g)+5O2(g)→3CO2(g)+4H2O(g) Calculate ΔH∘rxn for this reaction using standard enthalpies of formation. (The standard enthalpy of formation of gaseous propane is -103.9 kJ/mol.)
Sunday, April 6, 2014 at 10:29pm

chemistry
When 0.451g of biphenyl (C12H10) undergoes combustion in a bomb calorimeter, the temperature rises from 26.7∘C to 29.6∘C.Find ΔErxn for the combustion of biphenyl in kJ/mol biphenyl. The heat capacity of the bomb calorimeter, determined in a separate ...
Sunday, April 6, 2014 at 10:29pm

Chemistry
Insects and animals use the odor as sex attractants, as ways to find food, and nature to do its thing. For example, bees are attracted to flowers and in that process they pollinate grasses, flowers, fruits, etc.
Sunday, April 6, 2014 at 10:20pm

chemistry:)
C
Sunday, April 6, 2014 at 10:16pm

Chemistry
Why organic compound are volatile in nature
Sunday, April 6, 2014 at 10:16pm

Chemistry
Use PV = nRT and solve for n = number of mols of gas. Then n = grams/molar mass. YOu know n and grams, solve for molar mass.
Sunday, April 6, 2014 at 10:02pm

Chemistry
Thank you
Sunday, April 6, 2014 at 9:55pm

Chemistry
A sample of gas has a mass of 0.550g . Its volume is 111mL at a temperature of 75∘C and a pressure of 763mmHg . Find molar mass of gas
Sunday, April 6, 2014 at 9:54pm

chemistry
Just stopping by to say you all are going to Hell
Sunday, April 6, 2014 at 9:54pm

Chemistry
Cl2(gas) ==> 2NaCl which isn't balanced but the Cl is balanced and that's what the question is about. mols NaCl = grams/molar mass NaCl Using the coefficients in the balanced equation above to convert mols NaCl to mols Cl2. Then use PV = nRT and solve for V Cl2 in L.
Sunday, April 6, 2014 at 9:50pm

College Chemistry (DrBob222)
Yes, if you follow my directions above that will calculate Fe^2+. You have Eocell and Ecell which allows you to calculate Q. Then Q has the definition I gave and that has the concentrations in it. Q = (Fe^2+)/(Cu^2+). You know Q and Cu^2+, solve for Fe^2+. If you need help in ...
Sunday, April 6, 2014 at 9:46pm

Chemistry
dGo = -RTlnK Solve it. See if dGo is + or -
Sunday, April 6, 2014 at 9:33pm

Chemistry
What volume of Cl2 gas, measured at 687torr and 34∘C, is required to form 27g of NaCl?
Sunday, April 6, 2014 at 9:31pm

Chemistry
Final Volume=Initial Volume + Volume of water delivered Use the density of water and solve for volume: Density=mass/volume So, Volume=mass/density Volume of water delivered=2.67g/1.00g/mL Grams cancel out and you are left with volume (mL) Volume of water delivered=2.67mL Final...
Sunday, April 6, 2014 at 9:14pm

College Chemistry (DrBob222)
Thank you very much, but the problem indeed says 35 degree C. I was wondering if there is a way to calculate the Fe2+ (aq)?
Sunday, April 6, 2014 at 9:13pm

Chemistry
A volume of water delivered using a buret has a mass of 2.67 g. What was the final volume reading on the buret if the inital volume reading was 0.30 ml? [assume the density of water is 1.00g/mL]
Sunday, April 6, 2014 at 9:09pm

College Chemistry (DrBob222)
I presume you meant 25C and not 35. If you meant 35 then replace the 0.0592 below by (RT/2*F) Ecell = Eocell -(0.0592/2)log Q You have Ecell. Eocell = Eo for Cu^2+ + 2e --> Cu and add to Eo for Fe(s) ==> Fe^2+ + 2e That leaves Q. Q in this case is Q = (Fe^2+)/(Cu^2+) ...
Sunday, April 6, 2014 at 9:06pm

Chemistry
For a reaction that has an equilibrium constant of 9 × 10–9, which of the following statements must be true? A) ∆G° is positive. B) ∆G° is negative. C) ∆H° is negative. D) ∆H° is positive. E) ∆S° is positive.
Sunday, April 6, 2014 at 9:00pm

College Chemistry (DrBob222)
Use the Nernst equation to calculate the iron (II) concentration for the following iron/copper electrochemical cell when [Cu2+] = 0.012 M and Ecell = 0.750 V at 35°C. Cu2+ (aq) + Fe (s) --> Cu (s) + Fe2+ (aq)
Sunday, April 6, 2014 at 8:55pm

Chemistry
molsKClO3 = 9.50E25/6.02E23 = ? Convert mol KClO3 to mols mols KCl and mols O2 using the coefficients in the balanced equation. Then convert mols KCl to g. g = mols x molar mass Similarly, g O2 = mols x molar mass.
Sunday, April 6, 2014 at 8:34pm

Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | Next>>

Post a New Question | Current Questions

Homework Help: Science

Search
Members