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April 16, 2014

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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chemistry
The density of gold is 19.31g/cm3 and the density of platinum is 21.43 g/cm3. If equal masses of gold and platinum are transferred to equal volumes of water in separate graduated cylinders which graduated cylinder would have greatest volume change
Wednesday, February 19, 2014 at 5:53pm

chemistry
dv
Wednesday, February 19, 2014 at 5:26pm

chemistry
You didn't list any but the ions present will be Na^+ and SO4^2-
Wednesday, February 19, 2014 at 4:51pm

chemistry
The compound sodium sulfate is soluble in water. When this compound dissolves in water, which ion listed below would be present in solution?
Wednesday, February 19, 2014 at 4:08pm

Chemistry
3 moles of H2 produce 2 moles of NH3 3.65*10^-4 g of H2 is 3.621*10^-4 moles H2 That will produce 2.414*10^-4 moles of NH3 2.414*10^-4 * 6.023*10^23 = 1.454*20^20 molecules NH3
Wednesday, February 19, 2014 at 2:17pm

chemistry
75
Wednesday, February 19, 2014 at 1:21pm

Chemistry
scroll down to my reply to your earlier question, same method.
Wednesday, February 19, 2014 at 1:15pm

Chemistry help
2.57 mol of N2 --> 2 * 14 * 2.57 = 72 g of N2 that is 5.14 mol of N so 3*5.14 = 15.4 mol of H which is 1 g/mol 15.4 mol * 1 = 15.4 g of H so 72 + 15.4 = 87.4 grams of NH3
Wednesday, February 19, 2014 at 1:15pm

Chemistry
How many molecules (not moles) of NH3 are produced from 3.65x10-4g of H2?
Wednesday, February 19, 2014 at 1:01pm

Chemistry
How many grams of H2 are needed to produce 12.88g of NH3?
Wednesday, February 19, 2014 at 12:57pm

Chemistry help
How many grams if nh3 can be produced from 2.57mol of n2 and excess h2?
Wednesday, February 19, 2014 at 12:53pm

chemistry
%O = 100 - %C - %H Take a 100 g sample which gives 53.4g C 11.1g H 35.5g O mols C = 53.4/12 = ? mols H = 11.1/1 = ? mols O = 35.5/16 = ? Now find the ratio of the atoms to each other (as whole numbers) with the smallest number being 1.00. The easy way to do that is to divide ...
Wednesday, February 19, 2014 at 11:38am

chemistry
a compound contains only carbon hydrogen and oxygen analysis of a sample showed that it contained by mass 53.4% carbon and 11.1% hydrogen . what is the simplest formula for this compound .. step by step plese
Wednesday, February 19, 2014 at 10:46am

Chemistry URGENT
Please show how N and O are combined to make NO^+2 in Lewis dot structure. I'm having a hard time. Thanks
Wednesday, February 19, 2014 at 9:51am

Chemistry
1.5moles/30 seconds.
Wednesday, February 19, 2014 at 7:40am

Chemistry
P4 + 5O2 P4O10 , 1.5 moles of product were made in 30 seconds. What is the rate of reaction?
Wednesday, February 19, 2014 at 7:37am

Chemistry
gay
Wednesday, February 19, 2014 at 3:51am

chemistry
#3 is the answer, CuO is the limiting reactant
Tuesday, February 18, 2014 at 9:49pm

chemistry

Tuesday, February 18, 2014 at 9:48pm

Chemistry 1 H
How much barium chloride, BaCl, is necessary to react with the silver nitrate in the problem above?
Tuesday, February 18, 2014 at 9:42pm

chemistry
mol CuSO4 = grams/molar mass M = mols/L solution.
Tuesday, February 18, 2014 at 8:39pm

chemistry
c
Tuesday, February 18, 2014 at 8:15pm

Chemistry
-1368 kJ
Tuesday, February 18, 2014 at 7:47pm

chemistry
What is the molarity of a solution with a volume of 974 mL containing 17 g of CuSO4?
Tuesday, February 18, 2014 at 6:56pm

chemistry
What units?
Tuesday, February 18, 2014 at 5:46pm

Chemistry
q = mass(grams) x Hvaporization (J/g) This will give q in J/g, then change J to kJ.
Tuesday, February 18, 2014 at 5:44pm

CHEMISTRY
0.15g/molar mass = mols M = mols/6.5L pH = -log(HCl)
Tuesday, February 18, 2014 at 5:37pm

Chemistry
See your post above. For oxidizing agent and reducing agent here is what you do. Oxdn is loss of electrons--that substance is the reducing agent. Reduction is the gain of electrons--that substance is the oxidizing agent.
Tuesday, February 18, 2014 at 5:35pm

CHEMISTRY
I will do the first one in detail. The others follow the same pattern. Look up the activity series in your text/notes/Google/etc. If the METAL is above the metal ION, the metal will displace it; otherwise, there is no reaction. 3Mg + Al2(SO4)3 --> 3MgSO4 + 2Al Mg is ABOVE ...
Tuesday, February 18, 2014 at 5:33pm

Chemistry
Calculate the heat in kilojoules needed to vaporize 8.00kg of water at 100∘C.
Tuesday, February 18, 2014 at 5:22pm

Chemistry
CuSO4 + 2KOH ==> Cu(OH)2 + K2SO4 You have 150 x 1.50 = 225 millimols CuSO4 and 450 mmols KOH q = mass solution x specific heat x (Tfinal-Tinitia) I would use 300 mL = 300 g for mass soln. Specific heat H2O is 4.184 J/g*C Tfinal and Tinitial are given. q is Joules/225 mmols...
Tuesday, February 18, 2014 at 5:20pm

chemistry
You provided no information for the question. My crystal ball is hazy today.
Tuesday, February 18, 2014 at 5:13pm

chemistry
mols methanol = grams/molar mass Then m = mols/kg solvent
Tuesday, February 18, 2014 at 5:09pm

Chemistry
0.01M means 0.01 mols H3PO4/1000 mL solution. The molar mass is 98; therefore, there are 0.98 grams H3PO4/1000 mL solution. mass solution is 1000 mL x 1.11 g/mL = 1110 grams. mass % = (gH3PO4/g solution) = (0.98/1110)*100 = ? % w/w
Tuesday, February 18, 2014 at 5:07pm

chemistry
You have a solution that contains 340ml of water and 20ml of ethanol. Find the concentration of ethanol in this solution in each of the following units: (density of water is 1.00 g/ml, density of ethanol is 0.789g/ml)
Tuesday, February 18, 2014 at 5:02pm

Chemistry
The molarity of H3PO4 is .01 M. The density of the H3PO4 in the solution is .0009 g/mL. What is the mass percent of H3PO4 in the solution, which has a density of 1.11 g/ml?
Tuesday, February 18, 2014 at 4:27pm

chemistry
2
Tuesday, February 18, 2014 at 4:11pm

Chemistry
How can we help you with this assignment short of doing your homework for you. I recommend color for Ni. The Al and Sn are colorless while most Ni solutions are green or blue. Co solutions are pink to blue. Remember that Al is amphoteric; i.e., it forms a white gelatinous ppt ...
Tuesday, February 18, 2014 at 3:49pm

Chemistry
Heating NaHCO3 to what temperature? If to about 270 C or so it is 2NaHCO3 ==> CO2 + Na2CO3 + H2O mols NaHCO3 = grams/molar mass Using the coefficients in the balanced equation convert mols NaHCO3 to mols CO2. Then 22.4L x ?mols = ? L at STP
Tuesday, February 18, 2014 at 3:43pm

Chemistry
What is the volume ofCO2 measured at S.T.P which is involved on heating10.5g of NaHCO3
Tuesday, February 18, 2014 at 3:36pm

Chemistry
Solutions of NiSO4(aq), Al2 (SO4)3 (aq), CoSO4 , and SnSO4 (aq) are in bottles labelled A, B, C, and D. a) Design an experiment to identify which ionicsulfate solution is in which bottle. Give a list of equipment and chemicals required. Describe a step-by-step procedure for ...
Tuesday, February 18, 2014 at 12:55pm

Chemistry needs help
Indicate your specific subject in the "School Subject" box, so those with expertise in the area will respond to the question.
Tuesday, February 18, 2014 at 12:24pm

chemistry
What is the molality of a solution composed of 28.4 g of methanol CH3OH and 250 g of water
Tuesday, February 18, 2014 at 12:03pm

chemistry
12
Tuesday, February 18, 2014 at 11:45am

chemistry
2nacl
Tuesday, February 18, 2014 at 11:04am

chemistry
was the formation of reactants or products favored by the addition of heat?
Tuesday, February 18, 2014 at 10:24am

Chemistry
A 150.0 mL sample of a 1.50 M solution of CuSO4 is mixed with a 150.0 mL sample of 3.00 M KOH in a coffee cup calorimeter. The temperature of both solutions and the calorimeter was 25.2°C before mixing and 31.3°C after mixing. The heat capacity of the calorimeter is 24...
Tuesday, February 18, 2014 at 9:43am

CHEMISTRY
Hi!! pls i need help! 1) Mg + Al2(So4)3 2)Fe + CuSO4 3)Mg + CuSO4 4)Zn + CuSO4 5)Mg + FeSO4 FOR ALL 5: a)balanced eq b)ionic equation c) net ionic
Tuesday, February 18, 2014 at 6:57am

CHEMISTRY
the silvery luster
Tuesday, February 18, 2014 at 4:15am

Chemistry
Identify the oxidizing agent and the reducing agent in each of the reactions that proceeded spontaneously (the 5 above).....THANKYOU SO MUCH!! IF U HELP ITS VERY APPRECIATED!!!
Tuesday, February 18, 2014 at 3:48am

Chemistry
Hi!! pls i need help! 1) Mg + Al2(So4)3 2)Fe + CuSO4 3)Mg + CuSO4 4)Zn + CuSO4 5)Mg + FeSO4 FOR ALL 5: a)balanced eq b)ionic equation c) net ionic PLEASE HELP ME..THERE ARE SOO MANY MORE QUESTIONS I NEED TO DO!!!:(
Tuesday, February 18, 2014 at 3:47am

CHEMISTRY
0.15g of hydrogen chloride (HCl) is dissolved in water to make 6.5L of solution. What is the pH of the resulting hydrochloric acid solution?
Monday, February 17, 2014 at 11:21pm

scsu
What is the weight per volume percent (i.e. % density) of 0.5522 g acetic acid in the 10.00 mL sample?
Monday, February 17, 2014 at 10:26pm

Chemistry Help Please!!!
First you must recognize that k1 is the largest K of the group and the pH of the solution will be due largely to the first dissociation. The second and third don't produce enough to concern us too much. .......H3PO3 ==> H^+ + H2BO3^- I......0.05M.....0.......0 C......-x...
Monday, February 17, 2014 at 9:09pm

Chemistry
Mg + 2HNO3 ==> Mg(NO3)2 + H2 mols Mg = grams/molar mass mols Mg(NO3)2 = mols Mg (look at the mole ratio) which is 1 mol Mg to 1 mol Mg(NO3)2. Then grams Mg(NO3)2 = mols x molar mass. For HNO3 needed, convert mols Mg to mols HNO3 and convert mol HNO3 to grams as in the above.
Monday, February 17, 2014 at 8:59pm

Chemistry
in a chemical reaction, 5.2 grams of magnesium reacts with hydrogen nitrate. Calculate the amount of magnesium nitrate that is produced and the amount of hydrogen nitrate needed to react with the magnesium.
Monday, February 17, 2014 at 6:48pm

Chemistry Help Please!!!
1) Boric acid, H3 BO3, is a triprotic acid that dissociates in three reactions. The first dissociation step is: H3BO3 ⇌ H^+ + H2BO3^-, K(a1) = 7.3 x 10^-10; the second dissociation step is: H2BO3^- ⇌ H^+ + HBO3^-2, K(a2) = 1.8 x 10^-13; and the third dissociation ...
Monday, February 17, 2014 at 6:48pm

Chemistry?
What is your question?
Monday, February 17, 2014 at 5:05pm

chemistry
??
Monday, February 17, 2014 at 4:25pm

chemistry
Except for rubidium and caesium,___
Monday, February 17, 2014 at 4:11pm

chemistry
Larger and more complicated structures have more entropy than their lesser cousins. NaNO3 has more atoms, more bonds, higher molar mass, etc.
Monday, February 17, 2014 at 2:56pm

college chemistry
C = p*k k = C/p Convert 321.9 torr to atm. atm = torr/760 Convert 0.02538 g/L to mols/L = M mols = grams/molar mass Substitute into equation and solve for k.
Monday, February 17, 2014 at 2:51pm

chemistry
mols = grams/molar mass
Monday, February 17, 2014 at 2:45pm

chemistry
how many moles of vapor can be produced for 52 g of O2
Monday, February 17, 2014 at 1:56pm

Chemistry needs help
Indicate your specific subject in the "School Subject" box, so those with expertise in the area will respond to the question.
Monday, February 17, 2014 at 1:03pm

college chemistry
The solubility of Ar in water at 321.9 torr is 0.02538 g/L. What is Henry's Law constant (M/atm) for Ar in water?
Monday, February 17, 2014 at 12:34pm

chemistry
I am stuck on this one and was wondering if anyone can help me out! Why does sodium nitrate (166.5) have a bigger molar entropy than sodium bromide (86.8)? Thanks!
Monday, February 17, 2014 at 12:32pm

CHEMISTRY
A
Monday, February 17, 2014 at 8:16am

Chemistry
Solid phosphorus pentachloride yields phosphorus trichloride gas plus chlorine gas.
Monday, February 17, 2014 at 1:39am

Chemistry
write a sentence for the following reaction PCl5(s)=PCl3(s)+Cl2(g)
Monday, February 17, 2014 at 1:21am

AP Chemistry
The answer obviously is 69 nigga
Monday, February 17, 2014 at 1:07am

Chemistry
tr
Sunday, February 16, 2014 at 11:38pm

Chemistry
I don't know how to do the last algebra part that DrBob22 did not explain. I have not taken algebra since 2 years ago it would have been helpful to see... I haven't found out the math part anywhere!
Sunday, February 16, 2014 at 11:37pm

Chemistry
Equation: Fe+CuCl2>FeCl2+Cu We put two iron nails into the copper chloride solution:1. mass of empty dry beaker:103.64 2. mass of two iron nails, before reaction:1.20 3. mass of two iron nails after reaction: 1.01 4. mass of beaker and copper (dry):104.4 Through ...
Sunday, February 16, 2014 at 11:08pm

Quantum Chemistry
sdfg
Sunday, February 16, 2014 at 11:07pm

AP Chemistry
First you must calculate (H^+) for 0.90M acetic acid (HAc). .........HAc ==> H^+ + Ac^- I.......0.90.....0......0 C........-x......x......x E.....0.90-x.....x......x K = 1.8E-5 = (H^+)(Ac^-)/(HAc) Plug in the E line and solve for x = (H^+). So you want (H^+) in HCl to be ...
Sunday, February 16, 2014 at 10:51pm

College Chemistry
Describe how you could seperate the components of a mixture of PbCl2 and NaSO4 and recover the two substances.
Sunday, February 16, 2014 at 10:45pm

Chemistry
A and B dilute each other when mixed so the final solutions as they are mixed, but before they react is 0.050M x 45/70 = about 0.032M for A. but you should confirm this an all others that follow and do them more accurately than I. 0.100 M x 25/70 = about 0.0357M for B. ....A(...
Sunday, February 16, 2014 at 10:42pm

AP Chemistry
Approximately how much water should be added to 10.0 mL of 12.4 M HCl so that it has the same pH as 0.90 M acetic acid (Ka = 1.8 10-5)?
Sunday, February 16, 2014 at 10:16pm

Chemistry
Consider the equation A(aq) + 2B(aq) 3C(aq) + 2D(aq). In one experiment, 45.0 mL of 0.050 M A is mixed with 25.0 mL 0.100 M B. At equilibrium the concentration of C is 0.0410 M. Calculate K.
Sunday, February 16, 2014 at 10:10pm

Chemistry
Fe(s) + Cu^2+(aq) ==> Cu(s) + Fe^2+(aq)
Sunday, February 16, 2014 at 10:05pm

Chemistry
If the tongs used in the experiement were made of pure iron, what might happen if the tongs were allowed to remain in contact with the CuCl2 solution?
Sunday, February 16, 2014 at 9:59pm

Chemistry
I don't see a procedure so I can't be too helpful; however, here are some common errors if you used a solution. 1. Weighing errors. 2. Did you filter anything? If so some could have splattered out. Same thing for boiling away liquid such as water from a solution. 3. If...
Sunday, February 16, 2014 at 9:54pm

Chemistry
Equation: Fe+CuCl2>FeCl2+Cu The ratio of moles of copper produced to moles of iron reacted should be 1:1,but I get 60:17 in lab,can you state at least 3 errors for me?
Sunday, February 16, 2014 at 9:48pm

Chemistry
1. If all you are doing is identifying meal ions, the contamination of the HCl with Al will not affect the results at all UNLESS the Al energy overlaps one of those from the unknown. Why? Because it takes a certain amount of energy for the Al lines to appear and it takes A ...
Sunday, February 16, 2014 at 9:41pm

Chemistry
1. A student uses 6M HCl solution contaminated with Al(NO3)3 to wash the nichrome wire in between recordings of emission spectra for the different known and unknown metal ion solutions. The emission energies for the aluminum are 3.90x10^-19 J/atom, 3.58x10^-19 J/atom, and 2....
Sunday, February 16, 2014 at 9:25pm

Chemistry
.......CO + Cl2 ==> COCl2 I.....319...220......0 C......-x....-x......x E...319-x...220-x....x Substitute the E line into the Kp expression and solve for x, 319-x, and 220-x. Then add mols of each to find total mols. XCO = nCO/total mols XCl2 = nCl2/total mols XCOCl2 = ...
Sunday, February 16, 2014 at 9:24pm

AP Chemistry
(V1/T1) = (V2/T2)
Sunday, February 16, 2014 at 9:17pm

AP Chemistry
See your post on stoichiometry and solve with that process. When you find mols of each product, add together, use PV = nRT to solve for volume under the conditions listed.
Sunday, February 16, 2014 at 9:17pm

AP Chemistry
Use PV = nRT. For n find n for each and add for the total. n = grams/molar mass.
Sunday, February 16, 2014 at 9:15pm

AP Chemistry
You can add the PV = nRT equation to the density and come up with P*molar mass = density*RT
Sunday, February 16, 2014 at 9:14pm

AP Chemistry
Use PV = nRT and solve for n. Then n = grams/molar mass. Solve for molar mass.
Sunday, February 16, 2014 at 9:12pm

AP Chemistry
Here is the formula for solving theser stoichiometry problems. 1. Write the equation and balance it. 2. Convert what you have into mols. mols = grams/molar mass. 3. Using the coefficients in the balanced equation, convert mols of what you have (from step 2) to mols of the ...
Sunday, February 16, 2014 at 9:11pm

AP Chemistry
The long way of doing this, but the easier to explain, is as follows. Use PV = nRT and solve for n N2 in the 2L tank. Use PV = nRT and solve for n Ar in the 11 L tank. Then add nN2 + nAr = nTotal and use PV = nRT with a volume of 13 L (the sum of the 11 and 2 L tanks). That ...
Sunday, February 16, 2014 at 9:07pm

AP Chemistry
Use PV = nRT and calculate n. P in torr wet H2 = 966 torr P H2O torr = 22 torr PH2 dry = 966-22 = ? PH2 in atm = ?/760 V = 1.277 L n = unknown--Solve for this. R = 0.08206 L*atm/mol*K T = 297K Find n, then n = grams/molar mass. You know n and molar mass, solve for grams.
Sunday, February 16, 2014 at 8:49pm

AP Chemistry
The easy way to do this is to assign some convenient rate to SF6, then multiply that number by 1.5 to know the rate for X. Then plug into the formula for Graham's Law and calculate the molar mass of X.
Sunday, February 16, 2014 at 8:43pm

Chemistry
mols Al = grams/atomic mass = ? Using the coefficients in the balanced equation, convert mols Al to mols Fe. That is the theoretical yield. If you want it in grams then g = mols x atomic mass.
Sunday, February 16, 2014 at 8:41pm

Chemistry check and help
Yes, if no subscript is shown it is understood to be 1. For the first part all are ok except these two. SO2 = Tin(I)Oxide S is sulfur (not tin) and I would name this sulfur dioxide but I believe the IUPAC name would be sulfur(IV) oxide. BrF7 = Bromine(VI)Fluoride Wouldn't ...
Sunday, February 16, 2014 at 8:27pm

Chemistry
Fe2O3(s) + 2Al(s)-> 2Fe(l) + Al2O3(s) What is the theoretical yield of iron if we begin the reaction with 10.5 g of Al (assume an excess of Fe2O3)
Sunday, February 16, 2014 at 8:18pm

Chemistry check and help
so for all the chemical formulas if there is no subscript (for the valency of the element) does it mean it is a one or do i have to find the valency on the periodic table of elements? ex. P02 the P for Phosphorus doesn't have a number does it mean it is a one then ex.SO3 ...
Sunday, February 16, 2014 at 7:45pm

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