Sunday
February 7, 2016

Posts by DrBob222

Total # Posts: 51,318

Chemistry
1 mol contains 6.02E23 H2SO4 molecules. 3 mol contains 3*6.02E23 H2SO4 molecules. There are 2 atoms H per molecule H2SO4; therefore, there will be 6*6.02E23 atoms H in 3 mols H2SO4 molecules.
October 4, 2015

Chemistry
I don't know what ffg means. If you are look for strong, weak, non-electrolytes, then 3,5,6 are wrong.
October 3, 2015

CHEMISTRY !!!
I suggest you repost the problem at the top of the board and this time INCLUDE the k2 for H2SO3. We can't try to obtain a certain answer if we don't know what numbers you are using.
October 3, 2015

Chemistry
q = mass x specific heat x (Tfinal-Tionitial) q = -7500. Substitute and solve for Tfinal
October 3, 2015

Chemistry
The problem is worded funny and I can't tell if the final volume is 50 mL or 50.15 mL. If 50.15 as you are suggesting then 0.03 M x 0.15 mL/50.15 mL = ?M 0.03 M x 0.30 mL/50.30 mL = ?M If the final volume is 50 mL then 0.03 x 0.15/50 = ? 0.03 x 0.30/50 = ?
October 3, 2015

incomplete--Chemistry
No amounts given.
October 3, 2015

Chemistry
I don't know what you are talking about and you know your really are confused. The Al reacts with H2SO4 to produce hydrogen gas. All you are doing is saying that if you have 11.3 mols H2 gas produced it must have used 11.3 mols H2SO4 (which you calculated quite easily and ...
October 3, 2015

Chemistry
You are ok up to 11.3 mols H2 and 11.3 mols H2SO4. Then M = mols/L or L = mols/M = 11.3/6.6 = ? L
October 3, 2015

organic chemistry
I don't understand the question.
October 3, 2015

chemsitry
..........HQ ==> H^+ + Q^- I......0.035.....0.....0 C........-x......x.....x E.......0.035-x..x.....x Convert pKa to Ka, then substitute the E line into Ka expression and solve for x. Post your work if you get stuck.
October 2, 2015

chemistry
Let's call codeine hydrochloride CHCl which makes the cation CH^+ and the anion Cl^- .........CH^+ + H2O ==> H3O^+ + C I......0.064.............0......0 C........-x..............x......x E.......0.064-x Convert pKb to Kb Kb for the base = (Kw/Ka for the hydrochloride...
October 2, 2015

Chemistry
Mostly the angles. When assessing the stretching frequency of the C-H bonds or C-C bonds in ethane.
October 2, 2015

chemistry
Answered above.
October 2, 2015

chemistry
0.1 what?
October 2, 2015

Organic Chemistry
Here is a link. Pay attention to the S and R enantiomers. https://en.wikipedia.org/wiki/Benzoin
October 2, 2015

chemistry equilibrium
See your other post.
October 1, 2015

chemistry
First, it is phosphorus trichloride and pentachloride. Second you probably meant partial pressure. ..........PCl3 + Cl2 ==> PCl5 I..........0......0.......0.300 c..........x......x........-x E..........x......x.......0.0300-x Substitute the E line into the kc expression ad ...
October 1, 2015

Physical science
Problems like this often confuse because of the fraction and the large number; I often make up a similar problem without all of the distraction. For example, if we had a tire that had a tread depth of 1" and it was good for 2 miles, then 1"/2 mi = 1/2 inch/mile. You ...
October 1, 2015

Chemistry
Your calculation is correct. 9E3 means 9 x 10^3. Obviously you can't write this the usual way because that shows 5 s.f. Rounding one less number at a time gives us 8572, 8570, 8600 and 9000. Since we are allowed only one s.f., that can be written as 9000 (but many ...
October 1, 2015

Chemistry
8572.5 rounds to 1 s.f. as 9E3.
October 1, 2015

chemistry
grams Hg = mols Hg x atomic mass Hg. Then round to 3 s.f. Post your work if you get stuck.
October 1, 2015

AP Chemistry
a and c are right. b has no effect. You already have solid NaHCO3 present; adding a few more grams doesn't change anything. Remember solids do not show up in the keq expression. Or if you do want to include the solid, the (solid) = 1 by definition. Adding more solid and (...
October 1, 2015

Chemistry
I think you are stressed out over nothing. The answer I get is 0.04002945 which to two s.f. (limited I think by the 2 places in 30 minutes) is 0.040. I would go with answer 2.
October 1, 2015

Chemistry
The first part of your question I can't answer because you appear to have omitted a word in "...which has equal to ...." The second part of your question about tricky profs....probably so; however, I don't see any answers with any more than two s.f.
October 1, 2015

chemistry
Did you mean K2SO4? HgCl2(aq) + K2SO4(aq) ==> HgSO4(s) + 2KCl(aq)
October 1, 2015

chemestry
203% Cl? I doubt it. That must make X = -103%?
October 1, 2015

chemistry
Do you have the abundance data?
October 1, 2015

chemistry
Almost anything could go here but you may be thinking that "it doesn't increase the amount of the products".
October 1, 2015

oops @ anonymous---chemistry
Cl^- doesn't take away anything but H^+ does.
October 1, 2015

chemistry
Oxidation is loss of electrons. Reduction is gain of electrons. The material oxidized is the reducing agent. The material reduced is the oxidizing agent.
October 1, 2015

Chemistry
You want 1 ppm F. That is 1 mg/L F and 1 mg F x (molar mass NaF/atomic mass F) = ? mg NaF/L. 150 gal/person x 50,000 persons = ? gallons/yr Convert gallons/yr to L/yr. ? mg NaF/L x #L = mg NaF/yr Then convert mg NaF to kg NaF.
October 1, 2015

Chemistry
You want 75 ppm. That is 75 mg/L. But you don't need a L; you need only 4 mL so convert 75 mg/L to ?mg/4 mL and that is 75 x 4/1000 = ? mg in 4 mL.
October 1, 2015

Chemistry
Yes, ppm is mg/L. Do you really man 4.0 mL? That isn't much volume and I didn't even know they made 4.0 mL volumetric flasks. So 75 ppm will be 75 mg/L or 75 x 4/1000 = 0.3 mg Fe. 0.3 mg Fe x (molar mass Mohr's salt/atomic mass Fe) =
October 1, 2015

Science
What single replacement reaction?
October 1, 2015

conversion
1000 W = 1 KW
October 1, 2015

chemistery
(V1/T1) = (V2/T2) Remember T must be in kelvin.
October 1, 2015

conversion
I see you have several of these same posts. What do you not understand about this? Conversions are done with a factor and once you have the hang of it they are easy. But doing this for you will not help you learn how to do them yourself.
October 1, 2015

Chem
6Fe^2+ + Cr2O7^2- ==> 2Cr^3+ + 6Fe^3+ mols Cr2O7^2- = M x L = ? mols Fe^2+ = 6 x that. M Fe^2+ = mols Fe^2+/L Fe^2+ (Note: I didn't balanced the equation completely; actually we need only the redox part balanced.
September 30, 2015

Chemistry
To reiterate, the density of something does NOT change with volume. The density of 25 mL is the same as the density of 100 mL and that's the same as a zillion gallons of the stuff.
September 30, 2015

Chemistry
The specific gravity of 25 mL is the same as the specific gravity of 20000000 mL. Specific gravity is specific gravity and density is density. density = mass/volume. The larger the mass the larger the volume and the quotient is the same.
September 30, 2015

Chemistry
specific gravity = density.
September 30, 2015

Chemistry
Follow the equations. density = mass/volume volume = pi*r^2*h So pi and h don't change r is too small so volume is too small. Substituting too small a number in the density equation causes density to be what, too high or too low?
September 30, 2015

CHEM-CHECK ANSWER
Yes
September 30, 2015

Science
x^2 = (10)^2 + (24)^2 Solve for x.
September 30, 2015

Chemistry
Convert 18.9 kJ to kcal. That's for a 0.45 g sample. Change that to kcal/g. Post your work if you get stuck.
September 30, 2015

Chemistry
See your post above.
September 30, 2015

Chemistry
mass = volume x density Substitute and solve.
September 30, 2015

chemistry
At anode(+)electrode. 2F^- ==> F2 + 2e At the cathode (-) electrode 2Li^+ + 2e ==> 2Li I don't have any idea what the "usual" style guide is.
September 30, 2015

Chem
yes
September 30, 2015

Chem
mols K = grams/atomic mass K = ? mols Cl = grams/atomic mass Cl = ? mols O = grams/atomic mass O = ? (Note: mass O = 18.46-g K - g Cl) Now find the ratio of the elements to one another with the smallest number being 1.00. The easy way to do that is to divide the smallest ...
September 30, 2015

Chemistry
Look on your calculator, hit the log button and type in 1.104E-7 and hit the enter button or equal button. Then multiply by -1. I get 6.957 which I would round to 6.96.
September 30, 2015

Chemistry
speed light = frequency x wavelength 3E8m/s = 2.88E-9 x wavelength Solve for wavelength in meters.
September 30, 2015

chemistry
I assume this is 0.1M CuSO4 and 0.1M Al2(SO4)3 IN THE SAME SOLUTION. If they are prepared solutions that have been mixed it is calculated a different way. So it will be 0.1M in Cu^2+. 0.2 M x 2 = Al^3+ 0.1M + 0.3M = 0.4M in SO4^2-
September 30, 2015

chemistry
There are 6.022E23 molecules in 1 mol so there must be 5.3 times that in 5.3 mols.
September 30, 2015

chemistry
Sodium ethanoate is NaOEt and the OEt^- will be hydrolyzed. ..........EOt^- + HOH ==> EotH + OH^- I.......0.045..............0.......0 C.........-x...............x.......x E......0.045-x.............x........x Kb for OEt = (Kw/Ka for HOEt) = (x)(x)/(0.045-x) Ka is 1.77E-5. ...
September 30, 2015

chemistry
You are likely to scrape bits and pieces of filter paper. In addition you are likely to leave crystals on the paper.
September 30, 2015

chemistry
The hot fluid cools rapidly, the solute is less soluble in cooler solvent, pores become clogged.
September 30, 2015

Chemistry
S + 2CO ==> SO2 + 2C mols S = grams/molar mass = ? mols CO = grams/molar mass = ? Using the coefficients in the balanced equation, convert mols S to mols SO2. Do the same for mols CO to mols SO2. It is likely that these two values for mols SO2 will not agree which means one...
September 29, 2015

Chemistry
I never saw a problem like this before but your solution looks ok to me.
September 29, 2015

chemistry
Petroleum is not a single compound. https://en.wikipedia.org/wiki/Petroleum_ether
September 29, 2015

Chemistry
a. CrS Cr usually has +2 and +3 (although others are known and fairly common as +6) so CrS is chromous sulfide and part b is chromic oxide. b. Cr2O3 c. CrI3 X 6H20 This one is chromic iodide hexahydrate. d. CuCl e. CuI2 f. CuBr2 x 4H20 Cu usually is +1 or +2 so d is cuprous ...
September 29, 2015

Chemistry
mols Br = 5* mols FeBr5. g = mols x atomic mass = ?
September 29, 2015

Chemistry
The equation is ok. This is a limiting reagent (LR) problem and you know that because amounts are given for both reactants. mols TiCl4 = grams/molar mass = ? mols H2O = grams/molar mass = ? Using the coefficients in the balanced equation, convert mols TiCl4 to mols product. Do...
September 29, 2015

CHEMISTRY
hydroselenic acid The others are ok.
September 29, 2015

chem
K2Te is correct. For K2S it is potassium sulfide in the U.S. It has long been potassium sulphide in the UK but my understanding is that there is a concerted effort to change that in the UK to the "american" spelling. I am from the U. S. so I can't speak for an ...
September 29, 2015

General Chemistry
mL1 x M1 = mL2 x M2 100 x 0.65 = mL2 x 2.7M Solve for mL2.
September 29, 2015

chemistry
Why have you made it so difficult to read your question? I worked this yesterday, I think for you.
September 29, 2015

science
Read about flerovium. Only one atom was prepared. Element #114. http://www.webelements.com/flerovium/
September 29, 2015

science
Here is a link. Read about the discovery of elements 110 to ...... One of those I believe produced one atoms of the element.
September 29, 2015

chemsitry
See your other posts. By the way, you don't get extra points by using multiple screen names.
September 29, 2015

chemsitry
I answered your heterogeneous question earlier (with KNO3==>KNO2 + O2). What is it you don't understand about these problems. You need to learn how to do these yourself and depend upon others. And is there something about Chegg you don't trust?
September 29, 2015

chemistry
....2HI ==> H2 + I2 I...mols/L..mols/L...mols/L. You are given mols and L, calculate M. C.....-2x....x.....x E.....M-2x..M+x...M+x You are given M+x for H2, solve for x and evaluate the others. Post your work if you get stuck. Note my comments on your other posts. Multiple ...
September 29, 2015

CHEMISTRY
T of Fe goes down. T of water goes up. Heat flows from Fe to H2O Heat flow stops when T Fe = T H2O heat lost by Fe = heat gained by H2O
September 29, 2015

ap chemistry
2KNO3(s) <--> 2KNO2(s) + O2(g) Qc = (O2)
September 29, 2015

chemistry
K2SO4 + Ba(NO3)2 ==> 2KNO3 + BaSO4
September 29, 2015

Chemistry
You have all of the formulas and the numbers there, what's the problem? By the way, you must change 12.7 cm to m. Also, you don't have wavelenth in the formula; I would use E = hc/wavelength.
September 29, 2015

chem
Follow your previous CaCO3 problem. Convert 20 g HCl and 20 g CaCO3 to mols first. Remember this is a limiting reagent problem.
September 29, 2015

chem
CaCO3 + 2HCl ==> CaCl2 + H2O + CO2 mols HCl = M x L = ? Using the coefficients in the balanced equation, convert mols HCl to mols CaCO3. Now convert mols CaCO3 to grams. grams = mols x molar mass = ? For part 2. use the coefficients to convert mols HCl to mols CO2. hen ...
September 29, 2015

chem
How many mols do you want? That's mols = M x L = ? How many grams is that. grams = mols x molar mass = ?
September 29, 2015

chemistry
You would do well to find the caps key and use it for the formulas. What you have written is complete nonsense but I can translate it. Using the coefficients in the balanced equation, convert mols Al to mols Al2O3. Do the same to convert mols Cl2 to mols Al2O3. It is likely ...
September 29, 2015

CHEM
3 mg F^- x (molar mass NaF/atomic mass F^-) = ? mg NaF.
September 29, 2015

Chemistry
mass CuO + crucible = 54.0 mass Cu + crucible = 50.2 mass oxygen added = 54.0-50.2 = ? (NOTE:) As I recall the product is Cu2O and not CuO)
September 29, 2015

Chemistry
The highest density liquid is on the bottom, the lowest on the top, the middle one is in between.
September 29, 2015

Chemistry
Something is wrong with your problem. Either you have copied it wrong or the person making up the problem goofed. A 10 g mixture that is 60% C3H8 will produce 9.8 g H2O alone which leaves no water for the CxHy to produce.
September 29, 2015

chemistery
%w/w = (mass solute/mass solution)*100 =? % = [(65.2/(65.2+100)]*100 =
September 29, 2015

Chemistry
mass ice x specific heat solid ice x (Tfinal-Tinitial) = heat to move ice from -6 to zero C. mass ice x heat fusion = heat to melt ice mass ice x specific heat liquid water x (Tfinal-Tinitial) = heat to move T from zero C to +2 so Tfinal is +2 and Ti is 0. The sum of each step...
September 28, 2015

Radioactivity
ln(No/N) = kt No = 100 N = 50.2 k = solve for this t = 8 days Then k = 0.693/t1/2 Substitute for k and solve for t 1/2.
September 28, 2015

Chemistry
450 x (atomic mass Cu/molar mass CuFeS2) = ? g and convert to kg.
September 28, 2015

Chemistry
How many mols C do you have? That's 448/12 = ?mols There are 6.02E23 atoms in a mole of atoms.
September 28, 2015

chemistry
HCl = 1.05 x 0.2/100 = about 0.0021M ..........H2O ==> H^+ + OH^- I...............0.0021...0 C.................+x.....+x E.............0.0021-x....x Kw = (H^+)(OH^-) 1E-14 = (0.0021+x)(x) Solve for x and convert H^+ to pH. I don't think the ionization of H2O even enters...
September 28, 2015

Chemistry
Why not show your work and let me find the error instead of showing you how to do it.
September 28, 2015

need help with thsi equation
ZnSO4.xH2O(s)+ heat ---> ZnSO4(s)+xH2O(g)
September 28, 2015

need help with thsi equation
What about it?
September 28, 2015

chemistry
What's giving you trouble with this problem? The process of elimination should get the answer. O2, for example, you know is a gas, hydrochloric acid you know is an acid so it has a low pH, etc.
September 28, 2015

Science
probably so.
September 28, 2015

chemistry
I don't know what the 6H3PO4 means but I worked this problem for you yesterday. http://www.jiskha.com/display.cgi?id=1443379665
September 28, 2015

chemistry
mols Zn(NO3)2 = M x L = ? 1 mol Zn in 1 mol Zn(NO3)2 1 mol ZnO in 1 mol Zn g ZnO = mols ZnO x molar mass ZnO.
September 28, 2015

Chemistry
volume Al cube = 5 cm x 5 cm x 5 cm = ? cc = ? the same mL. Then add this volume to the 200 mL already there to find the new volume.
September 28, 2015

AP chemistry
0.51 mol/3 L = (H2S) in mols/L = M .........2H2S --> 2H2 + S2 I........0.17......0.....0 C.........-2x.....2x.....x E......0.17-2x....2x.....x Substitute the E line into the Kq expression and solve for x. Then evaluate each specie.
September 28, 2015

chemistry
Remember T must be in kelvin.
September 28, 2015

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