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Posts by DrBob222

Total # Posts: 54,990

@Damon--Chemistry
I don't think there is enough information to answer this question. I believe the answer posted is for a 500 GRAM solution but it won't be 500 mL. The density of a 37% H2SO4 solution is right at 1.05 g/mL so the volume will be about 476 mL. Have I missed the boat? I ...

Chemistry
Is this0.15 m or 0.15 M Is there a part b?

0.5mols of a monoalkanoicacid weighs 44 grams, determine the molecular formula and name the acid. (show the workings)
See your other post.

chemistry
mols = grams/molar mass. You have mols and grams, solve for molar mass. I get 88. The COOH group of an alkanoic acid weighs has a molar mass of 45 which leaves88-45 = 43. A methyl group (CH3) is 15 while the methylene group (CH2) is 14 so I would make an educated guess that ...

Basic science chemestry
Do you have a question? What you have posted is confusing. By the way you need to learn how to spell chemistry.

Chemistry
#1

Chemistry
I can draw the three for 1. For 2 I can draw two; i.e., 1-hydroxy propane and 2-hydroxy propane although those may not be proper IUPAC names. For 3 I can draw any structure for C2H4Cl and certainly not three. I can draw for at least one structure for C2H5Cl, at least one for ...

Chemistry
Let's call CH3COOH just HAc. It is dissociates 50%, that means it starts at 0.2M and ends up at 0.1M with the products 0.1M .........HAc --> H^+ + Ac^- I........0.2.....0......0 C....-0.5*0.2...0.1.....0.1 E.......0.1.....0.1.....0.1 Plug this into the Ka expression but...

chemistry
If you have pure Cu and you add oxygen to it, the Cu forms CuO and the Cu gains weight (mass) because of the added oxygen.

Chemistry
It does dissolve directly in water.

Chemistry
Basically, gases are compressible while liquids and solids are not. Doubling the temperature doubles the volume of a gas; certainly the volume of a solid and volume of a liquid are not doubled. Solids, liquids, and gases simply don't have the same properties.

Chemistry
CuO + H2 ==> Cu + H2O

Chemistry
See your other post.

Chemistry
Carbon dioxide, CO2, is not a chemical reaction by itself. However, it is a product of a chemical reaction. When fossil fuels burn or gasoline is used in cars, CO2 is one of the products formed. Usually water, H2O, is formed at the same time CO2 is formed.

Chemistry (chromatogrphy)aphy)
I assume from the last part of your post that you are using paper chromatography. If so,the paper is the stationary phase and the solvent is the mobile phase. Compounds that are very soluble in the mobile phase (in this case I think you used different solvent), they will move ...

Math/Chemistry
50.0 x 1E-5 = ? grams. Multiply by 1000 to convert to mg. Compare with 5.5E-3.

Chemistry
Why not just change the final weight of the crucible, make new calculations, and see what effect it is.

chemistry
Water is less dense at lower temperatures.

Chemistry
How many mols do you want? That's mols = M x L = ? Then = mols = grams/molar mass. You know mols and molar rmass, solve for grams.

Chemistry
See below

Chemistry
Note that 0.16m means 0.16 MOLAL while 0.16 M means 0.16 MOLAR. I am sure you meant 0.16 M. Na2CO3 + 2HCl == 2NaCl + H2O + CO2 mols HCl = M x L = approx 0.002 but you need a more accurate answer than that. Using the coefficients, convert mols HCl to mols Na2CO3. That's 1/2...

Chemistry
See your other posts.

Chemistry
1. mols CaI2 = grams/molar mass = ? 2. mass - volume x density = 12.0 mL x 1.000 g/mL = ? 3.m = mols/kg solvent 4. I'm confused about the term "molality of all solutes). I assume you want the m of Ca ion and m of I ion. m Ca^+ is the same as m CaI2. m I^- is 2x m CaI2.

Chemistry
This is a limiting reagent (LR) problem and you know that when amounts are given for BOTH reactants. Hg(ClO4)2 + Na2S ==> HgS + 2NaClO4 1a. mols Hg(ClO4)2 = grams/molar mass = ? b. mols Na2S = g/molar mass = ? 2a. Using the coefficients in the balanced equation, convert ...

Chemistry
In equal quantities like this I would write it as NaAc + HCl ==> HAc + NaCl So you essentially have a solution of HAc (now not 1M but 0.5M) and you calculate the pH of that solution. Do the same for solution II using the HH equation, then find the ratio of the pH o the two ...

Chemistry 2
#1. You need to find the caps key and use it. 2. You need to proof you post. "What is the boiling point of ethylene---I assume you meane ethylene glycol". mols ethylene glycol = grams/molar mass = ? kg solve is 0.074 kg delta T = Kb*m with Kb approx 0.5 but that an ...

Chemistry
pH 2 is(H^+) = 10^-2 M pH 12 is(H^) = 10^-12 M Assume a volume of 100 mL (0.1 L) of each, then mols pH 2 soln = M x L = 0.01 x 0.1 = 0.001 mols. mols pH 12 soln = 0.000000000001 x 0.1 = very small. Add the two volumes and you have 200 mL (0.2L) of essentially 0.001 mols so (H...

Chemistry
methanoic acid = HM millimols HM = 100 x 0.05 = 5. ...HM + OH^- ==> M^- + H2O I...5....0.......0..... add......x........... C..-x...-x.......x E..5-x...x.......x Substitute the E line into the Henderson-Hasselbalch equation and solve for x = millimols NaOH. Then M NaOH = ...

chemistry
Al^3+ + 3e ==> Al 2 O^2- ==> O2 + 4e

chemistry
Let's take a 20 g sample which means 10 g CaO and 10 g impurity. Convert 10 g CaO to ? g CaCO3. That's 10 x (molar mass CaCO3/ molar mass CaO)= about 18 g CaCO3 but you need a more accurate answer. Total mass sample now is 18 + 10 = approx 28 and % CaCO3 = (18/28)*100...

Chemistry
mL1 x M1 = mL2 x M2 25.0 x 7.50 = 500 mL x M2

Chemistry
I'm sorry but I don't have any equations or formulas to measure morality. If you want molarity, however, it is: mols NaHCO3 = grams/molar maqss Then M = molarity = mols/L solution

Chemistry
If you Google that long name you find an explanation that it has 1 chiral carbon which leads to 1 enantiometer. Find the 1 chiral C atom. If you can't find more than that, then 1 enantiometer is it.

Chemistry
See your post above.

chemistry
Not a. phen stands for 1,10 phenothroline. en stands for ethylenediammine tetraacetic acid. To answer this, draw a square for a and b and see if there are cis and trans isomers. For the others draw an octahedron and check for cis and trans isomers.

chemistry
You need to find the arrow key. 4Fe + 3O2 ==> 2Fe2O3 a. mols Fe = grams/atomic mass = ? Using the coefficients in the balanced equation, convert mols Fe to mols O2. b. mols Fe = grams/atomic mass = ? Using the coefficients in the balanced equation convert mols Fe to mols ...

Chemistry
confusing. Please rephrase the question.

Chemistry
Yes, T of calorimeter increases. q = heat transferred = heat capacity calorimter x (Tfinal-Tinitial)

Chemistry
For 1 the ionic equation is ok but you need a 2 for AgC2HO2 and a 2 for AgCl to balanced the molecular equation. 3Fe+2(aq) + 3SO-4(aq) + 6Na+(aq) + 2PO3-4(aq) ---> Fe3(PO4)2(s) + 6Na+(aq) + 3SO-4(aq) 3SO-4 should be 3[000SO4]^2- 2PO3-4 should be 2[PO4]^3- The CuCl2 equation...

Chemistry
dHrxn = (n*dHf products( - (n*dHf reactants) Substitute and solve

Chemistry
http://www.chemteam.info/SigFigs/SigFigRules.html https://www.chem.tamu.edu/class/fyp/mathrev/mr-da.html

Chemistry
62.9296(0.692) + x(1-0.692) = 63.546 Solve for x.

Chemistry
Assuming the 50 mL solution + 100 mL H2O equals 150 mL (that is that the solutions are additive, and technically, they are not additive), then that 100 on the right should be 150 and Mb = 0.3125/3 = ? Also note that you are allowed three significant figures so I would report 0...

Chemistry
Look at the order of filling. That is 1s, 2s, 2p, 3s, 3p, 4s, 3d etc. So if n = 3 and l = 2, the electrons must be a 3d electron. For n = 4 and l = 0, that's a 4s electron. The 4s is lower energy than the 3d. I think B.

chemistry
Draw an octahedran and plug the liqands onto the sides got c,d, and e (those have coordination of 6. Fopr a and b do a square and plug in the ligands. If you can do one of them in two different ways; i.e., so that two of the ligands are cis in one position and trans in another...

chemistry
Mg + I2 ==> MgI2 mols Mg = grams/molar mass Using the coefficients in the balanced equation, convert mols Mg to mols I2. that's a 1:1 reaction. Now convert mols Mg to grams. g = mols MgI2 x molar mass MgI2.

Chemistry
The rules I remember for reactions: 1. A rxn will occur if a (a meaning one) ppt forms. It goes without saying that if two ppts form there will be a reaction also. Your rxn is an example. 2. A rxn will occur if a gas is formed. Example: 2Na + H2O ==> 2NaOH + H2 3. A rxn ...

Chemistry
When Ca reacts with water the product is Ca(OH)2 and that is less soluble than, for example, NaOH when Na reacts with water. Both will give a bright pink color with phenolphthalein.

Chemistry
magnesium(solid) hydrochloric acid (solution) magnesium chloride (solution) hydrogen (gas)

Chemistry
When placed in water they form strong alkalies (bases).

Chemistry
3NaOH(aq) + FeBr3(aq)→ Fe(OH)3 + 3NaBr

Chemistry
Mg and Ca have only two electrons in the outside shell. K and Na have only one All are easily removed (Mg and Ca less so than K and Na) so they are quite reactive.

Chemistry
I don't understand the question.

Chemistry
I worked one like this yesterday. Only the numbers have changed. The process is the same. Try it. I'll help you through if you explain in detail what you don't understand.

chemistry
73.67 g is right but I would round that to 74. I don't know that there is a way to "DERVIVE" the formula. That's one of those things you learned in the 4th grade arithmetic class. But here is a common sense approach. If I gave you a basket containing 5 lbs of...

chemistry
That's 2 Al for 6e or 1 Al for 3e so that factor should be 2*26.98/6e or 26.98/3e. That doubles the answer. Some books use 96,485 instead of 96,500. Thanks for showing your work. That always makes it easier to find the error.

Chemistry
All of the answers for 1 are true but I don't think A is the best one. 2,3,4 are not right.

Chemistry
And what is the final temperature of the water?

Chemistry
An exothermic reaction has dH - so it must be B or E

Chemistry
I would look at D

AP Chemistry
I don't know how you're defining the term potential level. The potential to oxidize Cl ion to Cl2 gas is -1.36 v and that for Na ion to Na metal is -2.71 v. The potential of the cell is -1.36 + (-2.71) = -4.07 v. Therefore, you need at least +4.07 v to electrolyzs ...

Chemistry
http://wwwchem.uwimona.edu.jm/courses/selrules.html

Chemisrty
I have corrected the typo in the equation below. H3C6H5O7(aq) + 3NaHCO3(q)---Na3C6H5O7(aq) + 3H2O(l) + 3CO2(g) 1. mols NaHCO3 = grams/molar mass = 1/84 = 0.0119 Convert mols NaHCO3 to mols H3C6H5O7 using the coefficients in the balanced equation. That's 0.0119 x (1 mol ...

Chemistry
I don't know the meaning of 5A----10^20. "in a cobalt 'what' contain 5A---10^20 'what'"?

Chemistry
Materials, usually chemical molecules, in which one end of the molecule is positive and the other end is negative.

Chemistry
With regard to atomic weight or atomic mass see this. https://www.google.com/search?q=what+unit+is+atomic+mass&ie=utf-8&oe=utf-8 But one mole of the element will weigh that number shown in grams. with regard to the ionic radius of He and H, I don't have an answer. I didn&#...

Chemistry
You're ok. I substituted the numbers into equation 2 (with pKa = 5.3 and pH = 5.6

Chemistry
I tried that early on. The problem I had is that we have two equations and three unknowns. The unknowns are a, x, and pKa. I don't know how you solve for a in terms of x without involving pKa. So I'm inclined to think your solution is not correct but I don't know ...

Chemistry
I checked and you did respond to my question; however, you didn't answer it.

Chemistry
CH3COOH = HAc. .....HAc --> H^+ + Ac^- I....0.5.....0......0 C.....-x.....x......x E....0.5-x...x......x Ka = (H^+)(Ac^-)/(HAc) Substitute the E line into Ka expression and solve for H^+ initially in the 10 L. Then (OH^-) = Kw/(H^+) to calculate OH^- Double that. ...

Chemistry
All three of these reactions are double replacement. Therefore, all you need to do is to write the reaction and look up each compound to see what state it is. For example, NH4Cl(aq) + AgNO3(aq) → NH4NO3(aq) + AgCl(s) etc.

Chemistry
https://www.google.com/search?q=molar+volume+water&ie=utf-8&oe=utf-8

Chemistry
You need to look up the solubility of each of the compounds. That will give you the answer since one of them is essentially insoluble.

CHEMISTRY PLS HELP
delta T = i*Kf*molality. You know i = 3 from CaCl2. You know Kf (or you can look it up). I THINK it's about 1.9 or so. All you need is the molality. You have the M. Convert this way. Assume you have a liter of solution so the mass of solution is 1000 mL x 1.5 g/mL = 1500 ...

byu
See you post above.

Chemistry
M = mols/L solution You know M, you know mols, solve for L.

Chemistry
Correct. Go to the head of the class.

Chemistry
Technically I don't think you can work this problem without knowing the specific gravity of the solution. You can assume that the volume of the solution is the same as the mass (0.1 g = 0.1L as Sandu has done which means you assume the density of the solution is 1.00 g/mL...

Chemistry
The solution to this problem hasn't jumped out at me. Will you please check that all of the information from the problem has been posted?

chemistry
delta T = Kf*molality Substitute for delta T and Kf and solve for molality. m = mols/kg solvent substitute for m and kg solvent and solve for mols. mols = grams/molar mass Substitute for mol and molar mass and solve for grams glycerin.

chemistry
80 g = dish+xtals+H2O -40 g = dish+xtals ------ 40 g = dish+xtals -20 g = xtals ------ 20 g = dish

Chemistry
I think you have lucked onto the right answer but not the right reasoning. Two ways to look at it. First way. PV = nRT. V,R,T are constant(k) so pressure = k(n) So more mols the higher P; therefore, we go with water. Second way. Since the balloon is expandable, the end ...

Chemistry
You need to do these yourself. What do you not understand about this question? Aqueous solutions that end up with solids usually are pptn reactions. Loss/gain electrons in a reaction are redox reactions. Those that produce water, especially if they are from OH and H containing...

Chemistry
Frankly, I don't think you have copied the problem correctly. Where did the 16.042 in your work come from?

Chemistry
With some minor variations, all of these stoichiometry problems are alike. Step 1. Write and balance the equation. You have that. Step 2. Convert what you have to mols. That is mols = grams/molar mass = 350g/117 = approx 3 but you need to confirm all of these estimates here ...

oops--Chemistry
To clarify, I gave you ppm MgCl2 so ppm Cl^- is twice ppm for the MgCl2 "molecule". Like Scott, I too would consider throwing out the 175 value but as I re-read the question I don't think that is an option.

Chemistry
mean M = sum of M/5 = ? Then mean M x molar mass = grams/L. Change that to mg/L and that is ppm.

chemistry
Here is my work so far: 212 X 0.831 = 176.172 X 34.2 q = mass metal x specific heat metal x (Tfinal-Tinitial) q = 212 x 0.831 x (125.0-34.2) = ? q gained by water = mass H2O x specific heat H2O x (Tfinal-Tinitial) = ? By the way, I don't like the way you wrote your ...

Chemistry
You have 100 mL x 0.1M = 10 millimols HA and 10 mmols KA. ....HA + KOH = KA + H2O I...10....0....10........ add.......x............. C..-x....-x....+x E...10-x..0....10+x Substitute the E line into the Henderson-Hasselalch equation and solve for x = millimols KOH that must be ...

Chemistry
Here is the answer I posted yesterday. This information will help you find the answer yourself. If you don't understand something give me the details and I will help you through that part of it. http://www.jiskha.com/display.cgi?id=1475448164

Chemistry
Frankly I think this problem is lacking some information. As an estimate this is what I would do. pH at the half way point is 5.0 which means the pKa of HX is 5.0 and that makes Ka = 1E-5. At the eq point you have the hydrolysis of X^- (the anion) as .....X^- + HOH ==> HX...

Chemistry
match so the compound is zero charge as in NH4NO3 NH4HCO3 (NH4)2SO4 (NH4)2HOI4 etc.

Chemistry
You can read more about standard additions here. https://en.wikipedia.org/wiki/Standard_addition y = mx + b is straight line. m is slope = 0.103 b is the intercept = 0.135 and that will be - if the x intercept. Then solve for x = concentration in ppm. It is unclear in the ...

Chemistry
CxHyOz ==> xCO2 + 1/2yH2O Convert g CO2 and g H2O to g C and g H. 0.561 g CO2 x (atomic mass C/molar mass CO2) = grams C. 0.316 g H2O x (2*atomic mass H/molar mass H2O) = grams H. 0.255 - g C - g H = grams O. mols C = grams C/atomic mass C = ? mols H = grams H/atomic mass H...

General Chemistry
20 breaths x (500 mL/breath) = ? mL. Now convert mL to m^3. 1 cubic meter = 1E6 mL

Chemestry
There are 6.02E23 molecules in 1 mol of MgCl2. Each mols MgCl2 contains 3 ions.

Chemistry
2Na + S ==> Na2S mols Na = grams/atomic mass = ? Using the coefficients in the balanced equation, convert mols Na to mols Na2S. That's ?mols Na x (1 mol Na2S/2 mols S)= ?mols Na x 1/2 = ? Then grams Na2S = mols Na2S x molar mass Na2S

Chemistry
mols NH3 = grams/molar mass = ? Using the coefficients in the balanced equation, convert mols NH3 to mols NO. That's ?mols NH3 x (4 mols NO/4 mols NH3) = ?mols NH3 x 1/1 = ? Then grams NO = mols NO x molar mass NO

Chemistry
1.In the following chemical reaction, how many grams of the excess reactant are left over when 0.45 moles of Al react with 1.25 moles of Cl2 ? 2Al + 3Cl2 → 2AlCl3 LR = limiting reagent. ER - excess reagent. Actually you work three regular stoichiometry problems here. ...

Chemistry
See your post above.

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