Friday
January 30, 2015

Posts by DrBob222


Total # Posts: 46,653

Chemistry
0.053M means you have 0.053 mols NaCl/Liter of solution. Since M = mols/L you can rearrange that to M x L = mols and 0.053 x 5L = ? mols in 5L of solution. If you want to convert that to grams it is grams = mols x molar mass = ?
November 29, 2014

Chemistry
You can go about this two ways. (g solute/ mL)*100 = % (g CaCO3/250 mL)*100 = 5% Solve for g CaCO3. The other way is that 5% w/v means 5g CaCO3 in 100 mL, you want 250 so 5g CaCO3 x (250/100) = g needed for 250 mL instead of 100 mL. By the way I don't think this is ...
November 29, 2014

chemistry
Your process is correct and the answer would be correct but you threw away part of the answer in the 0.07. You're allowed 3 significant figures by the 4.50 so you don't round the 0.0714 answer you should have obtained to 0.07. In fact, I like to keep one extra place ...
November 29, 2014

chemistry
Use PV = nRT n = mols N2 = grams/molar mass
November 29, 2014

Chemistry
You set it up anyway you wish. If p1 = 744-17.35 = 726.45 (but I get closer to 726.65) then v1 = 495 mL and T1 = 273 + 20 = ?K If you do it that way then P2 is 760 V2 = ? T2 = 273 but you could turn all of that around. The point is that it makes little difference if you solve ...
November 29, 2014

Chemistry
You've done well so far. Now use (P1V1/T1) = (P2V2/T2) and solve for final volume. Remember to round the final answer to the correct number of significant figures, expecially if your prof is picky about that kind of thing.
November 29, 2014

science
volume = width x length x height = ? cubic meters density in kg/m^3 = 45/? = x? If you want it in other units I recommend you convert m to cm and kg to g then units will be in g/cc.
November 29, 2014

chemistry
(NaOH) = 2M x (2 mL/100 mL) = ? (OH^-) = (NaOH) pOH = -log(OH^-) pH + pOH = pKw = 14. You know pOH and pKw, solve for pH.
November 29, 2014

chemistry
HCl + NH3 ==> NH4Cl b) millimols NH3 = M x mL = approx 12.5 but you need to confirm this an all of the calculations that follow. Then millimols HCl needed = 12.5 M HCl = millimols/mL = 0.5. Solve for mL = mmols/M = 12.5/0.5 = about 25 mL. a) You have pure NH3 at the ...
November 29, 2014

chemistry
I'll help you through this but please explain what you know to do and especially what you don't understand about the problem.
November 29, 2014

Chemistry
Write and balance the combustion equation for ethanol + O2 ==> CO2 + H2O as eqn 1. Then reverse that equation multiply it by an integer to make mols CO2 cancel with mols CO2 in the next equation you write (also, change the sign for delta H and multiply by the same factor ...
November 28, 2014

Chemistry
Look up the delta Ho formation of each. (Al is zero but the others have numbers for each.) Then dHrxn = (n*dHformation products) - (n*dH formation reactants_
November 28, 2014

Chemistry
Show your work and I'll find the error. n CO2 = grams/molar mass
November 28, 2014

Chemistry
You do it all with an ICE chart. ...........2NO ==> N2 + O2 I........0.160.....0.....0 C..........-2x.....x.....x E.......0.160-2x...x.....x Substitute the E line into the Keq expression and solve for x and 0.150-x. Post your work if you get stuck.
November 28, 2014

Chemistry
dHrxb = (n*dHformation products)-(n*dHformation reactants)
November 28, 2014

chemistry
1 cubic micrometer = 1E-15 L.
November 28, 2014

chemistry
You're close and your process is right but the math is a little off. By the way, that's dihydrate and not dehydrate. The formula of the dihydrate is CuCl2.2H2O; therefore, you should have added in 2 mols H2O and not 1. The molar mass of CuCl2.2H2O is closer to 170. ...
November 27, 2014

Chemistry
total heat needed = heat to raise Cu kettle + heat to raise the water. total q = [(mass Cu kettle x specific heat Cu x (Tfinal-Tinitial)] + [(mass H2O x specific heat H2O x (Tfinal-Tinitial)] Solve for total q.
November 27, 2014

Chemistry
I don't know what "compose the micelle" means; however, if you could find the caps key and use it, the products in the equation are correct and it is balanced but be aware that agno3 and AgNO3 are not the same.
November 27, 2014

chemistry
Any test you run in a med tech lab will be a practical application. A1C, fasting glucose, lipids, BUN, etc.
November 27, 2014

chemistry
d is correct.
November 27, 2014

Chemistry
dG = dHfus - Tfusion*dSfusion 0 = ..... Then dHfusion = Tfusion*dSfusion.
November 27, 2014

chemistry
Isn't that A? dG = dH - TdS. If dH is - and dS is +, then -TdS will be negative; thus dG will ALWAYS be negative.
November 27, 2014

Chemistry
0.12 dm^3 x (1 mol/24 dm^3) = ? mols N2 mols Cu = ? mols N2 x (3 mols Cu/1 mol N2) = ? Then g Cu = mols Cu x atomic mass Cu = ?
November 26, 2014

chemistry
See your other post.
November 26, 2014

chemistry
I don't think there is a chemical reaction for shampoo. Shampoo is largely a group of cleansing agents mixed together.
November 26, 2014

Chemistry
molecular equation is 2Na3PO4(aq) + 3MgCl2(aq) ==>Mg3(PO4)2(s) + 6NaCl(aq) total ionic BUT you add the phases. 6Na^+ + 2PO4^3- + 3Mg^2+ + 6Cl^- ==> Mg3(PO4)2(s) + 6Na^+ + 6 Cl^- net ionic. cancel those ions that appear on both sides of th equation and you will be left ...
November 26, 2014

Chemistry
Your other post under Kate should give you some hints on how to do this. The spectator ions are the ionx that ARE NOT in the net ionic equation.
November 26, 2014

CHEMISTRY
Cu^2+ ==> Cu you balance. NH3 ==> N2 you balance
November 26, 2014

CHEMISTRY
Can you be more specific. This is a bit too general for me to know where you're trying to go.
November 26, 2014

chemistry
One qual application is for a business to analyze a competitors product to see what it contains. One quant application is. Almost every food product on the market must show on the label the contents of the container. Almost every manufacturer or every product I know must have ...
November 26, 2014

CHEMISTRY HELP
Do you have any thoughts on the subject?
November 26, 2014

chemistry
When dG is negative the reaction is spontaneous.
November 25, 2014

chem please help
I agree with c.
November 25, 2014

chemistry
Use PV = nRT; solve for P
November 25, 2014

chemistry
right, b is the answer.
November 25, 2014

chemistry
c is the answer. For my money I wish physics had kept it.
November 25, 2014

Chemistry help drbob222
I agree with d.
November 25, 2014

Chemistry
This is just another stoichiometry problem like the HNO3/NO problem below with a slight twist. Solve for theoretical yield in grams, as before, then %yield = (AY/TY)*100 = 94.5 and solve for AY.
November 25, 2014

Chemistry
mols H2O = grams/molar mass Using the coefficients in the balanced equation, convert mols H2O to mols NO. Convert mols NO to g. g NO = mols NO x molar mass NO. This is the theoretical yield (TY). The actual yield (AY) is 125g. % yield = (AY/TY)*100 = ?
November 25, 2014

Chemistry
delta T = Kf*m. You know delta T (normal freezing point - new freezing point) and Kf, solve for m = molality. m = mols/Kg solvent. You know m and kg solvent (use density for kg solvent; i.e., mass = volume x density). solve for mols. mols = grams/molar mass. You know mols and ...
November 25, 2014

POTASSIUM SULPHATE FERTILIZER GRANULE PROCESS
What's the concentration of the HCl?
November 25, 2014

chemistry
I will assume you intended to write 0.3m, meaning 0.3 molal since you don't seem to be able to find the caps key on your computer. m = mols solute/kg solvent 0.3 = mols BaCl2/0.150 Solve for mols BaCl2, then mols = grams/molar mass. You know molar mass and mols, solve for ...
November 25, 2014

chemistry
Why all the screen names? Work this one the same way when your name was Destiny.
November 25, 2014

chemistry
See Destiny et al.
November 25, 2014

chemistry
See your other screen names.
November 25, 2014

chemistry
mols = M x L = ?
November 25, 2014

chemistry
See your post under Mackenzie.
November 25, 2014

chemistry
See your other screen names posts.
November 25, 2014

chemistry
Done the same way no matter what your screen name is. See those posts.
November 25, 2014

chemistry
At least you came up with a different kind of problem. M = mols/L solution.
November 25, 2014

Chemistry
Check this to confirm. CuSO4 + 6NH3 + 2H2O = (NH4)2SO4 + Cu(NH3)4(OH)2
November 24, 2014

chemistry 2
The long way is to use PV = nRT and solve for pressure of each gas. n = grams/molar mass or atomic mass when dealing with grams. Then add the partial pressures to find the total pressure.
November 24, 2014

Chemistry
mols = M x L = ? Then mols x molar mass = grams.
November 24, 2014

Chemistry
C + O2 ==> CO2 393.5 kJ x (6g/12g) = kJ heat released to burn 6g C. X grams C = 12 x (39.3/393.5) =
November 24, 2014

Chemistry
........H2 + I2 ==> 2HI E.......x..0.015....0.030 Plug into the Keq expression and solve for x.
November 24, 2014

chemistry-naming
C3H8 probably is propane. KCl is potassium chloride
November 24, 2014

Chemistry
0.60 M Na^+. There are 3 Na atoms in 1 Na3PO4 molecule; therefore, (Na3PO4) must be 0.60/3 = 0.20M Na3PO4.
November 24, 2014

Chemistry
I think Damon worked this below.
November 24, 2014

Chemistry
http://www.nwscc.edu/nsfdc/organicchemistry/constitutional%20isomers
November 24, 2014

chemistry
No and I answered no to the response I gave yesterday. One reason you know 105g can't be correct is because to obtain 160.9 g Au from AuCl3, the AuCl3 must be more than 160.9g because AuCl3 is not 100% Au.
November 24, 2014

chemistry
Frankly, I think the whole idea of valence electrons with transition metals is nonsense unless the rules make sense and most don't. I've spent almost two hours looking at page after page for an explanation of valence electrons. No two sites give the same rules for ...
November 24, 2014

CHEMISTY HOMEWORK HELP ASAP
1. Use the Henderson-Hasselbalch equation. Substitute into the HH equation and calculate pH. 2. Set up an ICE chart using .......CH3COOH + OH^- --> CH3COONa + H2O and substitute the E line of the ICE chart into the HH equation and sole for the new pH.
November 24, 2014

Chemistry Homework Help Please!
See my response above.
November 24, 2014

Chemistry
NaF is the base HF is the acid.
November 24, 2014

Chemistry
millimols NaF = mL x M = approx 100 mmols HF = mL x M = aprox 62.5 mmols HCl added = approx 3.75 You omitted the exponent on Ka. I think that's 7.1E-4, then pKa = 3.14 ................F^- + H^+ ==> HF I..............100....0.......62.5 add.................3.75 C...
November 24, 2014

Chemistry Homework Help
See your post above.
November 24, 2014

chemistry
It works this way. If you multiply the equation you use the same multiplier for dH. If you reverse the equation, change the sign of dH. If you reverse the equation AND multiply it, then multiply by the same multiplier and change the sign.
November 24, 2014

Chemistry Physics
yes
November 24, 2014

Chemistry Physics
c = fw c = speed of light in m/s f = frequency in Hz w = wavelength in m
November 24, 2014

Chemistry
Use PV = nRT and n = grams O2/molar mass O2.
November 24, 2014

soran university
You must have graphs for solubility or tables of solubility. Without those I can't help.
November 24, 2014

chemistry
I can't decipher your post. Please repost and this time use caps where needed, ask your question(s), and don't leave out the adjectives in describing your question.
November 24, 2014

chem/science
It would help if we had the reaction you used.
November 24, 2014

Chemistry 211
I would go with a and b. \
November 24, 2014

Chemistry
Do you mean is 14.6 g CaCO3 is formed? mols HCl = grams/molar mass Convert mols HCl to mols CaCl2. Convert mols CaCl2 to grams. g = mols x molar mass.
November 24, 2014

Chemistry
I think your last step is a little off; I have 82.3 mL. I agree with your numbers up to multiplying by 22.4.
November 24, 2014

Chem please help
I agree with c.
November 24, 2014

Chemistry
The dilution formula is c1v1 = c2v2 c = concentration v = volume
November 23, 2014

Chemistry
K fwd = 0.65 K rvse = 1/0.65
November 23, 2014

chemistry
This is nothing more than plug and chug pH = pKa + log (base)/(acid) base = propanoate acid = propanoic acid You must look up the value for pKa propanoic acid.
November 23, 2014

Chemistry
q = mass H2O x specific heat H2O x (Tfinal-Tinitial)
November 23, 2014

chem
incomplete
November 23, 2014

Chemistry
2KClO3 ==> 2KCl + 3O2 mols KClO3 = grams/molar mass. Using the coefficients in the balanced equation, convert mols KClO3 to mols O2. Now convert mols O2 to grams. g = mols O2 x molar mass O2 = ?
November 23, 2014

chemistry
mols glycerin = grams/molar mass = ? mols H2O = grams/molar mass = ? mols fraction glycerin = Xgly = mols glycerin/total mols. Then pH2O = Xglycerin*PoH2O
November 23, 2014

Chem please help
Yes, C is correct. Gases always have more entropy than liquids.
November 23, 2014

Chemistry - Heat of Fusion of Ice
I don't know exactly how you determined the heat fusion so I can't answer question #3. #1 is No. #2 is No. #3 is I don't know. I don't know how the experiment was done.
November 23, 2014

Biochemistry
I found your other post and saw your non-response BUT you told me what the numbers stood for. Find that post, give me the concns of the HCl and stomach acid, and I can verify your work.
November 23, 2014

Biochemistry
I responded earlier that I couldn't make sense of this because of the spacing (or lack thereof). You haven't helped at all because you haven't changed the spacing. I have used ...... as spacers OR you can write on separate lines but you can't make the page ...
November 23, 2014

Chemistry
(P1V1/T1) = (P2V2/T2)
November 23, 2014

Biochemistry
Apparently you don't get it at all. I know what you're asking and it's a fairly simple question BUT I can't make heads or tails of your post. Look at the post. There are no spaces. I can't tell the difference in your post between the #1, #2 and #3 trial (if...
November 23, 2014

Biochemistry
I can't make head or tails of this. Remember you can't make more than one(1) space. This forum recognizes only 1.
November 23, 2014

chemistry
mols = g/molar mass. Substitute and solve for mols. Then mols = M x L. Substitute and solve for L and convert to mL.
November 23, 2014

Chem
mols Br2 = grams/molar mass Using the coefficients in the balanced equation, convert mols Br2 to mols AlBr3.
November 23, 2014

Chemistry
See your other post.
November 23, 2014

Chemistry
160.9 g Au must have more weight as AuCl3.
November 23, 2014

Chemistry
160.9 g Au x (molar mass AuCl3/atomic mass Au) = ? mass AuCl3.
November 23, 2014

Chemistry
Let's call formate ion for-. It will hydrolyze as follows: .........for- + HOH ==> Hfor + OH^- I........1.19.............0.....0 C.........-x..............x.....x E.......1.19-x............x.....x Kb for for- = (Kw/Ka for formic acid) = (x)(x)/(1.19-x) Solve for x = OH...
November 23, 2014

Chemistry
yes
November 23, 2014

Biochem
See your other post.
November 23, 2014

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