Sunday
April 20, 2014

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Post a New Question | Current Questions

Chemistry
Calculate the pH of the solution that results from mixing 30.0 mL of 0.050 M HCN(aq) with 70.0 mL of 0.030 M NaCN.
Wednesday, March 19, 2014 at 9:20pm

AP Chemistry
Thank You. This question totally broke me
Wednesday, March 19, 2014 at 9:03pm

AP Chemistry
I think Ag comes out first followed by H2, then Fe if ever.
Wednesday, March 19, 2014 at 8:57pm

Chemistry
Why do you divide .01 by 2. Shouldn't you divide by 1 because 50 ml+50ml=1L
Wednesday, March 19, 2014 at 8:52pm

Chemistry
4
Wednesday, March 19, 2014 at 8:45pm

chemistry
Johnny said he didn't have a calculator and wants someone to do his work. I did one problem. Then Danny says his calculator returns the wrong answer so it may be broke(n). Then I find Danny and Johnny are the same computer. :-(. Do we have an answer moocher?
Wednesday, March 19, 2014 at 8:20pm

AP Chemistry
A solution is 1.0M in AgNO3 and Fe(NO3)2.in the electrolysis of this solution using inert electrodes, the voltage is gradually increased. What is the order in which the substances in the solution would plate our or react at the cathode ? Assume that the overvoltage of hydrogen...
Wednesday, March 19, 2014 at 8:09pm

Chemistry
Use the Henderson-Hasselbalch equation.
Wednesday, March 19, 2014 at 7:57pm

Chemistry
The b part is a common ion problem; i.e., F^- is the ion common to both KF and MgF2. For part b, Ksp = (Mg^2+)(F^-)^2 The common ion shifts the solubility to the left. MgF2 ==> Mg^2+ + 2F^- because of Le Chatlier's Principle. The new solubility will = new (Mg^2+) and ...
Wednesday, March 19, 2014 at 7:57pm

Chemistry
If your equation is right use 2 mol e. However, I'm somewhat surprised In doesn't go to In^3+.
Wednesday, March 19, 2014 at 7:41pm

Organic Chemistry
Lauren, I'm sorry but we can't draw structures on this forum_search_20140419. You might try Google but that sounds so specific I don't know how much luck you will have.
Wednesday, March 19, 2014 at 7:35pm

CHEMISTRY
I need to find the rate law of a reaction but ive only done so when factors cancel out, this one has all different numbers and im not quite sure what to do with it. It has time taken every second (which im assuming are the different trials) and different concentrations of OH...
Wednesday, March 19, 2014 at 7:25pm

Chemistry
It starts at 0.01/2 = 0.005 and you want it to go to 1E-4 ln(5E-3/1E-4) = 2E10*t Solve for t.
Wednesday, March 19, 2014 at 6:52pm

Organic Chemistry
Draw every stereoisomer for 1-bromo-2-chloro-1,2-difluorocyclopentan​e. Use wedge-and-dash bonds for the substituent groups, and be sure that they are drawn on the outside of the ring, adjacent to each other.
Wednesday, March 19, 2014 at 6:44pm

Chemistry
Calculate the change in mass of the In electrode after the cell supplies 100 mA of current for 10 minutes. The balanced redox reaction is 2In+Cl2=2In+ + 2Cl-. I understand the idea behind the question, I just don't know if I should use 1 mol In per 1 mol e- or 1 mol In per...
Wednesday, March 19, 2014 at 6:27pm

Chemistry
The reaction OH- + NH4+ = H20 + NH3 is kinetically first order in both reactants' concentrations. The rate constant is 2e10 1/M s. If 50 ml of .01 M NaOH is mixed with 50 ml of .01 M NH4CL, find the time required for the OH- concentration to reach 1e-4 M.
Wednesday, March 19, 2014 at 6:04pm

Chemistry
A saturated solution of MgF2 at 23 degrees C was prepared by dissolving solid MgF2 in 1 L water. The Ksp of MgF2 is 1.5e-5. a.)Calculate the mass of MgF2 dissolved. b.) When .1 mols of solid KF was dissolved in the MgF2 solution, precipitation was observed. Find the mass of ...
Wednesday, March 19, 2014 at 5:59pm

Chemistry
What is the concentration of hydronium ions in a solution that is 0.12 M HBrO(aq) and 0.160 M NaBrO(aq)?
Wednesday, March 19, 2014 at 5:56pm

Chemistry
I need to find the rate law of a reaction but ive only done so when factors cancel out, this one has all different numbers and im not quite sure what to do with it. It has time taken every second (which im assuming are the different trials) and different concentrations of OH...
Wednesday, March 19, 2014 at 5:47pm

chemistry
Calculate the H3O+ concentration present in water under the following conditions. Enter your answer in scientific notation. a. [OH-] = 2.8 x 10-7 M b. [OH-] = 8.8 x 10-3 M c. [OH-] = 2.4 x 10-11 M everytime I do the problem In the calculator I get system error someone please ...
Wednesday, March 19, 2014 at 5:05pm

Chemistry
Calculate the pH of a solution in which a. [H3O+] = 7.8 x 10-7 M pH = b. [H3O+] = 5.1 x 10-6 M pH = c. [H3O+] = 6.1 x 10-5 M pH = d. [H3O+] = 9.3 x 10-4 M pH = I get 8.1 9.5 9.1 6.7 but its wrong please someone help!
Wednesday, March 19, 2014 at 5:03pm

chemistry
Just as I thought, it was much easier than I was making it out to be haha Thank you!
Wednesday, March 19, 2014 at 4:39pm

chemistry
So you get 1418 kJ for every 2*61 g nitromethane. How much will you get for 6900 g. 1418 kJ x (6900/2*61) = ?
Wednesday, March 19, 2014 at 4:28pm

chemistry
I feel like this question is pretty easy, but I can't seem to figure out how to go about solving it. It's like the solution is on the tip of my tongue: Nitromethane (CH3NO2) burns in air to produce significan amounts of heat. 2 CH3NO2(l) + 3/2 O2(g) -> 2 CO2(g) + 3 ...
Wednesday, March 19, 2014 at 4:22pm

Rate Law - Chemistry
I need to find the rate law of a reaction but ive only done so when factors cancel out, this one has all different numbers and im not quite sure what to do with it. It has time taken every second (which im assuming are the different trials) and different concentrations of OH...
Wednesday, March 19, 2014 at 4:22pm

chemistry
p1v1 = p2v2
Wednesday, March 19, 2014 at 3:56pm

chemistry
a gas with a volume of 4.00 L at pressure of 205kPa is allowed to expand to a volume of 12.0L. what is the pressure in the container if the temp remains constant
Wednesday, March 19, 2014 at 3:49pm

Chemistry
I need to find the rate law of a reaction but ive only done so when factors cancel out, this one has all different numbers and im not quite sure what to do with it. It has time taken every second (which im assuming are the different trials) and different concentrations of OH...
Wednesday, March 19, 2014 at 3:12pm

chemistry
I don't know the answer because it varies with what kind of concentration you have. g/L, M, m,% w/v, %w/w, % v/v. Frankly I think this is a poor question.
Wednesday, March 19, 2014 at 2:26pm

Chemistry
This may come as a shock to you but m and M don't mean the same thing. m stands for molality and M stands for molarity. I ASSUME you meant M and not m. mols = M x L = ? You might find the caps key on your keyboard and use it. K2CrO4 means something to me. k2cro4 doesn't.
Wednesday, March 19, 2014 at 2:21pm

chemistry
Knowing the concentration of a solution allows us to find all of the following except A. the mass of a solute. B. the mass of the solvent. C. the volume of the solvent. D. the concentration of a solution when conditions change.
Wednesday, March 19, 2014 at 2:19pm

Chemistry
2KClO3 = KClO4 + KCl a. The equation isn't balanced. b. I don't see any potassium chlorite.
Wednesday, March 19, 2014 at 2:15pm

Chemistry [back-titration] - please check my sol'n
One mistake is the 1:1 ratio for Fe^2+ vs Cr2O7^2-. The partially balanced equation is 6Fe^2+ + Cr2O7^2- ==> 2Cr^3+ + 6Fe^3+ A second error is I have the molar mass TeO2 as 159.6 I worked the problem and 13.09% TeO2 is correct. I didn't go through the rest of your work ...
Wednesday, March 19, 2014 at 2:11pm

chemistry
2C4H10 + 13O2 ==> 8CO2 + 10H2O mols butane = grams/molar mass = ? Using the coefficients in the balanced equation, convert mols butane to mols O2. Use PV = nRT and solve for V O2 at the conditions listed.
Wednesday, March 19, 2014 at 1:43pm

Chemistry
You've done part A. Amount in part A/0.83 = amount you need at 83% efficiency.
Wednesday, March 19, 2014 at 1:38pm

Chemistry
Last week we drew Lewis dot structures of azide (N31-), a crucial component in automobile collision safety airbags. During an impact, a sensor ignites a detonator cap that sets off the following rapid reaction: 2NaN3(s) → 2Na(s) + 3N2(g) Part A What mass of ...
Wednesday, March 19, 2014 at 1:21pm

Chemistry
Thank you, I know how to do it.
Wednesday, March 19, 2014 at 12:16pm

Chemistry
these are (p*v)/t problems p=pressure v=volume t=temperature (in kelvin) it doesnt mention pressures in these problems so we assume it remains constant. the problems should be set up as: (Volume of initial)/(temp. of initial) = (volume of final)/(temp. of final) plug in and ...
Wednesday, March 19, 2014 at 11:37am

chemistry
If a tank contains 55.2 g of butane, what volume, in liters, of oxygen is needed to burn all the butane at 0.850 atm and 25 degrees Celsius? Need to show work too.
Wednesday, March 19, 2014 at 11:26am

Chemistry [back-titration] - please check my sol'n
A 7.00 gram sample containing the mineral tellurite was dissolved then treated with 70.0 mL of 0.03114 M K2CrO7. 3 TeO2 + Cr2O7 ^2- + 8 H+ -> 3 H2TeO4 + 2 Cr3+ + H2O When reaction is complete, the excess Cr2O7 2- required a 14.05 mL back titration with 0.1135 M Fe2+. ...
Wednesday, March 19, 2014 at 11:22am

Chemistry
[OH─] = 0.10 M [OH─] = 0.20 M t(min) Abs ln(Abs) Abs ln(Abs) 0 1.000 0.000 1.000 0.000 1 0.905 -0.100 0.678 -0.389 2 0.811 -0.209 0.451 -0.796 3 0.735 -0.308 0.288 -1.245 4 0.664 -0.409 0.185 -1.687 this is what the table looks like because my explanation of it ...
Wednesday, March 19, 2014 at 11:17am

Chemistry
KClO3 = KClO4 + KCl What is the conversion factor to convert between moles of potassium chlorite and moles of potassium perchlorate?
Wednesday, March 19, 2014 at 11:17am

Chemistry
I need to find the rate law of a reaction but ive only done so when factors cancel out, this one has all different numbers and im not quite sure what to do with it. It has time taken every second (which im assuming are the different trials) and different concentrations of OH...
Wednesday, March 19, 2014 at 11:15am

Chemistry
I'm having trouble trying to figure out how to setup and solve these problems: 1) 2,600.0 mL of air is at 20.0C. What is the volume at 60.0C? 2) A gas occupies 900.0 mL at a temperasture of 27.0C. What is the volume at 132.0C? 3) What change in volume results if 60.0 mL of...
Wednesday, March 19, 2014 at 11:00am

Chemistry
Calculate the number of moles of ag in 5ml of .004m agno3 and the number of moles of cr04 in 5ml of .0024m k2cro4
Wednesday, March 19, 2014 at 10:33am

Chemistry
1) Consider (P1V1)/T1 = (P2V2)/T2 Volume is constant so its P1/T1 = P2/T2 2) Convert C to K 3) Plug in (Pressure and temperature have an inverse relationship unlike the direct relationship between pressure and volume.)
Wednesday, March 19, 2014 at 9:53am

Chemistry
Hi, Bob. But how to get (MMPbCl2/2*MMNaCl) and (MMPbSO4/MMK2SO4). Because it is confusing to me. Can you show the step more clearly. Thank you? I just can do step 1, which is X=10-Y. But step 2, it is bit confused. I can't get the meaning.
Wednesday, March 19, 2014 at 7:02am

Chemistry
Sorry, I have forgotten to give the information. This question has part a, which is "What mass of sodium azide must be completely reacted to inflate an air bag to 65.0 liters at 20.0 ºC and 1.06 atm?" Please help me because I have calculated many time, ...
Wednesday, March 19, 2014 at 6:51am

Chemistry (titrations)
Thank you! I understand it now. :)
Wednesday, March 19, 2014 at 6:49am

Chemistry
mols N2 = 57.5/22,400 = ? mols Li = 6x that (from the coefficients in the balanced equation). Then g Li = mols Li x atomic mass Li = ?
Wednesday, March 19, 2014 at 12:54am

Chemistry
What mass of lithium (in g) is required to react completely with 57.5mL of N2 gas at STP? Lithium reacts with nitrogen gas according to the following reaction: 6Li(s)+N2(g)→2Li3N(s)
Wednesday, March 19, 2014 at 12:45am

Chemistry
Yes BUT you need the heat of combustion of CH4 to know howmuch heat it produces. How much heat do you need? (1 qt H2O = 0.946 L and if the density of H2O is 1.00 g/mL that is 946 g)That's q = 946 g H2O x specific heat H2O x (Tfinal-Tinitial). Let's suppose this is y ...
Wednesday, March 19, 2014 at 12:30am

chemistry
And what is your problem? a. pOH = -log(OH^-). Substitute and solve. b. Use pH + pOH = pKw = 14 and solve for pH, then use pH = -log(H3O^+). c. See b. pH + pOH = pKw = 14
Wednesday, March 19, 2014 at 12:18am

Chemistry
I have no idea how to solve for the volume of methane. Any help?
Wednesday, March 19, 2014 at 12:16am

chemistry
HCl + KOH ==> KCl + H2O Note the ratio is 1 mol KOH = 1 mol HCl. mols KOH = M x L = ? mols HCl = mols KOH MHCl = mols HCl/L HCl Done.
Wednesday, March 19, 2014 at 12:15am

chemistry
pKa = -log Ka
Wednesday, March 19, 2014 at 12:13am

Chemistry
You have everything here except the heat of combustion of CH4.
Wednesday, March 19, 2014 at 12:13am

Chemistry
It isn't and I don't. The surface area of liquid in a beaker would be done this way. Measure the diameter of the beaker. Then pi*r^2 = area. Yes, you can vary the surface area by changing the size of the beaker. That will work for any cylindrical container. It would be...
Wednesday, March 19, 2014 at 12:11am

Chemistry
To bad I missed out on that (or those). :-) And while I'm here let me correct an error above in one of my posts. In one of them I gave dG = -2.303RTlnK as the correct formula and it isn't. The correct formula is either dG = -2.303RTlogK OR dG = -RTlnK
Wednesday, March 19, 2014 at 12:05am

Chemistry
Look up mascaline on the web like I did. Here it is. http://en.wikipedia.org/wiki/Mescaline I don't see an alcohol or an acid but I do see an amine group. Also three ether groups.
Tuesday, March 18, 2014 at 11:57pm

Chemistry
2.) For the reaction, calculate how many grams of the product form when 18.4g of Br2 completely reacts. Assume that there is more than enough of the other reactant. 2K(s)+Br2(l)→2KBr(s) mols Br2 = grams/molar mass = estimated 0.1 but you should be more accurate than that...
Tuesday, March 18, 2014 at 11:53pm

Chemistry
I need to vary the surface area by choosing different size beaker. I will put liquid in there so it would have to be volume??cm^3? But the question is how can I calculate the surface area of the beaker ??? The key thing here is the container... Examples: 27cm^3??? 250 ml ...
Tuesday, March 18, 2014 at 11:47pm

Chemistry
I've never done this but I would guess it would be Cr4O3; i.e., for every 4 mols Cr you use 3 mol O2 for #1 with Cr as the limiting reagent. For #2, O2 is the LR. 2.5 O2 x 4 mol Cr/3 mol O2 = 3.33 so the formula is Cr3.33O2.5. Convert to whole numbers and that is Cr10O7.5 ...
Tuesday, March 18, 2014 at 11:44pm

Chemistry
Natural gas is almost entirely methane, CH4. What volume of natural gas at 20 C and 1.00 atm pressure is required to heat one quart of water from 20 C to 100 C? The density of methane at 20 C is 0.665 g/mL. The reaction for the combustion of methane is CH4 (g) + 2 O2 (g) -->...
Tuesday, March 18, 2014 at 11:40pm

chemistry
7.969
Tuesday, March 18, 2014 at 11:28pm

Chemistry
1000 J = 1 kJ is the factor so 220 J x (1 kJ/1000 J) = ? You see you multiply the value you start with by the factor. You can place the factor as 1000/1 or as 1/1000. Only one way is right. The right way will ALWAYS cancel the unit you don't want and keep the unit you want...
Tuesday, March 18, 2014 at 11:22pm

Chemistry
This compound is mescaline, a hallucinogen. Which of the following statements is true? Mescaline is an amine. Mescaline contains an alcohol group. Mescaline is a carboxylic acid. Mescaline is an amine and contains an alcohol group.
Tuesday, March 18, 2014 at 11:16pm

Chemistry
220 J to kilojoules 350 kj to calories 97.0 kcal to joules 35.0 cal to kilocalories How do I convert them?
Tuesday, March 18, 2014 at 11:02pm

Chemistry
For the reaction shown, find the limiting reactant for each of the following initial amounts of reactants. 4Cr(s)+3O2(g)→2Cr2O3(s) 1.) 1 molCr; 1 molO2 2.) 4 molCr; 2.5 molO2 3.) 12 molCr; 10 molO2 4.) 14.8 molCr; 10.3 molO2 Express your answer as a chemical formula. I&#...
Tuesday, March 18, 2014 at 10:56pm

Chemistry
Hello! I'm doing these questions for my chemistry homework, and I can only figure out the first one, I don't know how to do the rest, I'm completely stuck! Please help!! Thank you! 1.) For the reaction, calculate how many grams of the product form when 18.4g of Ca ...
Tuesday, March 18, 2014 at 10:55pm

Chemistry
I COULD KISS YOU RIGHT NOW
Tuesday, March 18, 2014 at 10:44pm

chemistry
Sometimes the basicity of a solution is reported using pOH (pOH = -log[OH-]). What is the a. [OH-] if pOH = 1.90 b. [H3O+] if pOH = 12.94 c. pH if pOH = 9.70
Tuesday, March 18, 2014 at 10:42pm

chemistry
It requires 23.2 mL of 0.250 M KOH to titrate 49.0 mL of an HCl solution of unknown concentration. Calculate the initial HCl concentration.
Tuesday, March 18, 2014 at 10:39pm

chemistry
C6O2H8, Ka = 1.7 x 10-5 calculate pka
Tuesday, March 18, 2014 at 10:36pm

General Chemistry
Ag2SO4 will begin to ppt when Ksp = (Ag^+)^2(SO4^2-) is exceeded. (SO4^2-) = Ksp/(Ag^+)^2 (SO4^2-) = Ksp/(0.290)^2 Solve for SO4^2- and substitute into Ksp for CaSO4. Solve for Ca^2+
Tuesday, March 18, 2014 at 10:35pm

Chemistry
Actually nothing happens. You now have a mixture of Na^+, Cl^-, OH^-, H^+, all mixed in with water.
Tuesday, March 18, 2014 at 10:23pm

General Chemistry
CaSO4 Ksp= 4.93E^-5 Ag2SO4 Ksp= 1.20E^-5
Tuesday, March 18, 2014 at 10:22pm

Chemistry
pH=-logHconcentration Hconcentration=10^-pH a. 10^-6.66= 2.19E-7 c. 10^-13.17=1.70E-14
Tuesday, March 18, 2014 at 10:20pm

General Chemistry
Do you have the corresponding Ksp values?
Tuesday, March 18, 2014 at 10:20pm

Chemistry
What is the concentration of H3O+ in a solution with the following pH values. Enter your answer in scientific notation. a. 6.66 b. 13.40 c. 13.17 d. 2.39
Tuesday, March 18, 2014 at 10:15pm

Chemistry
Suppose you tried to carry out a double replacement reaction by mixing equal voulumes of a solution that contains dissolved NAOH and a solution that contains dissolved NACL. WHat would you expect to happen when the two solutions were mixed? Expain?
Tuesday, March 18, 2014 at 10:12pm

General Chemistry
Sodium sulfate is slowly added to a solution containing 0.0500 M Ca2 (aq) and 0.0290 M Ag (aq). What will be the concentration of Ca2 (aq) when Ag2SO4(s) begins to precipitate?What percentage of the Ca2 (aq) can be separated from the Ag (aq) by selective precipitation?
Tuesday, March 18, 2014 at 10:07pm

chemistry
what type of bonding is phosphoric acid?
Tuesday, March 18, 2014 at 9:49pm

chemistry
I guess d. The others are not.
Tuesday, March 18, 2014 at 9:47pm

chemistry
in which of the following pairs of compiunds are both members of the pair ionic compounds? a) PI3 and HBr, b) H2S and NCl3, c)LiF and H2O, d)LiI and NiO
Tuesday, March 18, 2014 at 9:42pm

Chemistry
thank you
Tuesday, March 18, 2014 at 9:33pm

Chemistry
............Sn(OH)2 ==> Sn^2+ + 2OH^- I............solid.......0........0 C............solid.......x........2x E............solid.......x........2x Ksp = (Sn^2+)(OH^-)^2 5.45E-27 = (x)(2x)^2 Solve for x = solubility in mols/L. Then grams = mols x molar mass
Tuesday, March 18, 2014 at 9:28pm

Chemistry
I understand. I leave those intermediate answers in the calculator; writing them down and re-entering often leads to rounding errors. I think 63.8985 which I would round to 64.0 is the correct answer.
Tuesday, March 18, 2014 at 9:25pm

Chemistry
The Ksp of tin(II) hydroxide, Sn(OH)2, is 5.45 × 10-27. Calculate the solubility of this compound in g/L.
Tuesday, March 18, 2014 at 9:23pm

Chemistry
How did u get it
Tuesday, March 18, 2014 at 9:22pm

Chemistry
2.00x10^-3
Tuesday, March 18, 2014 at 9:07pm

CHEMISTRY
1 H2O 2 H3O+ 3 NO3- 4 OH- 5 HNO3
Tuesday, March 18, 2014 at 9:05pm

Chemistry
1
Tuesday, March 18, 2014 at 8:55pm

Chemistry
I'm using .0083145 for R because the -10.31 is in kJ
Tuesday, March 18, 2014 at 6:55pm

Chemistry
25g/molmassMethane=H/890kJ solve for H
Tuesday, March 18, 2014 at 6:55pm

Chemistry
an energy quanta level.
Tuesday, March 18, 2014 at 6:53pm

Chemistry
I'll even try the inverse -2.478/-10.33 =lnK .2399 = lnK e^(.2399)= 1.27 = incorrect
Tuesday, March 18, 2014 at 6:37pm

Chemistry
I think I tried that. Let me show u my notes: -10.30 kJ = -(.0083145)(298) lnK -10.30 kJ = -2.478 lnK -10.30/-2.478 = lnK 4.157 = lnK e^(4.157) = 63.88 = Incorrect.
Tuesday, March 18, 2014 at 6:33pm

Chemistry
What does each electron outside of a nucleus occupy?
Tuesday, March 18, 2014 at 6:17pm

Chemistry
What is the enthalpy change if 25.0 g of methane are burned? 890kJ of heat released for every mole of methane that reacts. CH4 + 2O2 = CO2 + 2H2O
Tuesday, March 18, 2014 at 5:31pm

Pages: <<Prev | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | Next>>

Post a New Question | Current Questions

Homework Help: Science

Search
Members