Wednesday
October 22, 2014

Posts by hannah


Total # Posts: 2,890

Chemistry(Please check)
.50 - x / x = 3.20e-1 I need to solve for x. I was going to do .50 X 3.20e-1 and then take the square root but this is not correct. I am not sure what to do. Thank you for your help. Math(Please help) - Reiny, Tuesday, April 17, 2012 at 3:18pm You probably meant (.50 - x)/x = ...
April 19, 2012

Chemistry(Please respond)
Step 1:H2O2 + I^-^ = H2O + OI^-^ step 2: H2O2 + OI^-^ = H2O + O2 + I^-^ What is the equation for the overall reaction? I am not sure how to do this since there are two equations. Complete the rate law for the overall reaction. I know how to do this one but I am not sure of ...
April 19, 2012

Math(Please respond)
.50 - x / x = 3.20e-1 I need to solve for x. I was going to do .50 X 3.20e-1 and then take the square root but this is not correct. I am not sure what to do. Thank you for your help. Math(Please help) - Reiny, Tuesday, April 17, 2012 at 3:18pm You probably meant (.50 - x)/x...
April 18, 2012

Chemistry
Please disregard question.
April 18, 2012

Chemistry
A 21.2mL sample of 0.307M ammonia, NH3 is titrated with 0.259 M hydrobromic acid. What is the pH before the addition of any hydrobromic acid? I am not sure how to start this. I know I could completeit if I knew where to start. Would I set up a moles table?
April 18, 2012

Chemistry(Please respond)
Calculate the pH of an aqueous solution of 0.15 M potassium carbonate. I know that pH = -log(H30+) but I am not sure how to start this problem. Chemistry(Please help) - DrBob222, Saturday, April 14, 2012 at 11:09pm Hydrolyze the CO3^2-. CO3^- + HOH ==> HCO3^- + OH^- Do an ...
April 18, 2012

Chemistry(Please respond, thank you)
Step 1:H2O2 + I^-^ = H2O + OI^-^ step 2: H2O2 + OI^-^ = H2O + O2 + I^-^ What is the equation for the overall reaction? I am not sure how to do this since there are two equations. Which species acts as a catalyst? I know that I^-^ is the catalsyt. Which species acts as a ...
April 18, 2012

Math(Please help)
.50 - x / x = 3.20e-1 I need to solve for x. I was going to do .50 X 3.20e-1 and then take the square root but this is not correct. I am not sure what to do. Thank you for your help.
April 17, 2012

Chemistry(Thank you for your help)
Step 1:H2O2 + I^-^ = H2O + OI^-^ step 2: H2O2 + OI^-^ = H2O + O2 + I^-^ What is the equation for the overall reaction? I am not sure how to do this since there are two equations. Which species acts as a catalyst? I know that I^-^ is the catalsyt. Which species acts as a ...
April 17, 2012

Chemistry(Please help)
How do I set up an ice table when I only have .15M?
April 17, 2012

Chemistry(Please help)
Calculate the pH of an aqueous solution of 0.15 M potassium carbonate. I know that pH = -log(H30+) but I am not sure how to start this problem. Chemistry(Please help) - DrBob222, Saturday, April 14, 2012 at 11:09pm Hydrolyze the CO3^2-. CO3^- + HOH ==> HCO3^- + OH^- Do an ...
April 17, 2012

History, World
How many innocent South Vietnamese citizens were killed during the Vietnam war?
April 16, 2012

Chemistry(Please help)
Calculate the concentration of HC6H6O6- in an aqueous solution of 0.0851 M ascorbic acid, H2C6H6O6 (aq). I do not know how to start this
April 15, 2012

physics
Calculate the power of a device that requires 1.98 mA at 25.5 V. I know how to do the problem. i am just confused on how to convert megaAmps(which is mA right?) to amps. i think there are 1million amps in one mega amp? is that correct or is it the other way. so would you do 1....
April 15, 2012

Chemistry
What is the percent by weight of a solution prepared by dissolving 25 g of NaCl in 150 g of water? What is the volume of water in a 1 L bottle of 37% rubbing alcohol by volume?
April 15, 2012

Chemistry
A buffer solution is prepared by adding 14.37g of NaC2H3O2 and 16.00g of acetic acid to enough water to make 500mL of solution. What is the initial concentration of C2H3O2 in the solution? Ka(HC2H3O2)=1.8e-5 HC2H3O2 = H3O+ + c2h3O2 the molar mass of NaC2H3O3 = 82.04 I know ...
April 14, 2012

Chemistry(Please help)
so for kb I do 1e-14/.15?
April 14, 2012

Chemistry(Please help)
Calculate the pH of an aqueous solution of 0.15 M potassium carbonate. I know that pH = -log(H30+) but I am not sure how to start this problem.
April 14, 2012

biology
is insomnia the same thing as sleep deprivation. im pretty sure they are different but i just wanted to check. also what in the brain causes insomnia. What parts of the brain create it adn what are the functions?
April 14, 2012

math
How many 2 quart pitchers could you fill with 512 fluid ounces of juice?????
April 12, 2012

Chemistry
If you add 0.35grams NaF to 150mL of a 0.30M HF, what is the pH of the resulting solution? To start off would I use the value of 1.4e-11 for F^-^ and 7.2e-4 for HF? Chemistry(Please help) - DrBob222, Tuesday, April 10, 2012 at 12:04am This is a buffer problem. pH = pKa + log(...
April 10, 2012

Chemistry(Please check)
So it would be 27x^4, so I divide 5.0e-33 by 27 to get 1.8e-34 and then raise this to the 1/4 power which I got 4e-9.
April 10, 2012

Chemistry(Please check)
What is molar solubility of Al(OH)3 at 25 degrees C given the solubility product Ksp = 5.0e-33? I set this up as Al^3+ + 3OH^- Ksp=[Al^3+][OH^-]^3 5.0e-33 = (x)(3x)^3 Before I go any further did I do this correctly?
April 10, 2012

Chemistry
You have 250mL of a 0.56M solution of sodium acetate. How many mL of 0.50M acetic acid should be added to make a buffer of pH 4.40? I think this is a buffer system so I would use pH=pka + log base/acid so would I set this up as 4.40 = 4.74 + log base/ 1.8e-5 from acetic acid?
April 10, 2012

Chemistry(Please help)
So it would be pH=4.74 + log base/acid and I use 7.2e-4 for HF but after I convert g NaF in 150mL to M is this what I use for the base?
April 9, 2012

Chemistry(Please help)
If you add 0.35grams NaF to 150mL of a 0.30M HF, what is the pH of the resulting solution? To start off would I use the value of 1.4e-11 for F^-^ and 7.2e-4 for HF?
April 9, 2012

Chemistry(Please check)
. Ksp for Fe(IO3)3 is 10-14. Two solutions, one being iron(III) nitrate and the other being sodium iodate, were mixed. At the instant of mixing, [Fe3+] = 10-4M and [IO3-] = 10-5M. What happens? My answer is that a precipitate forms because Qsp > Ksp. Would you agree? ...
April 9, 2012

Math
For an experiment on the titration of a supernatant liquid I need to calculate the number of moles of S2O3^2-^ ion required using the volume of SrIO3 solution(supernatant liquid) from the two trials that were conducted. For both trials the volume of SrIO3 was 9.5mL. So first I...
April 9, 2012

Chemistry
A saturated solution of a certain metal(II) chloride has a chloride ion concentration of 0.032M. The Ksp for this compound can be determined to be is? This is similar to another question I posted that gave the Ksp and I had to find the pH. I am not sure how to start this ...
April 9, 2012

Chemistry(Please help)
For the second way, where did the 2.29e-5 come from?
April 9, 2012

Chemistry(Please help)
For an acetic acid-sodium acetate buffer to have a pH of 4.64, what molar ratio of CH3COOH to Na+ CH3COO– is needed? I know that the Ka value for acetic acid is 1.8e-5 and that I have to divide this value by the value of sodium acetate but I do not understand how you get ...
April 9, 2012

Chemistry(Please check answers)
1)What is the pH of a saturated solution of lead(II) hydroxide? The Ksp= 4.0e-15 Pb(OH)2 4.0e-15 = (x)(2x)^2 = 4x^3 I divided by 4 and took the cube root and got 1.12e-5 but I am not sure I took the cube root correctly. -log(1.12e-5)= 4.95 14-4.95 = 9.05 The answer choices ...
April 9, 2012

Chemistry(Please check)
. Ksp for Fe(IO3)3 is 10-14. Two solutions, one being iron(III) nitrate and the other being sodium iodate, were mixed. At the instant of mixing, [Fe3+] = 10-4M and [IO3-] = 10-5M. What happens? My answer is that a precipitate forms because Qsp > Ksp. Would you agree?
April 8, 2012

Chemistry(Please check)
. The insoluble salts AV, B2W, C2X3, DY2, and EZ3, which were formed from the metal ions A+, B+, C3+, D2+, and E3+ and the nonmetal ions V1– , W2–, X2–, Y1–, and Z1–, all have the same Ksp value. The salt with the highest molar solubility is AV B2W ...
April 8, 2012

Chemistry(Please check)
Which of the following mixtures will be a buffer when dissolved in 1 liter of water? 0.10 mol Ba(OH)2 and 0.20 mol HCl 0.30 mol KCl and 0.30 mol HCl 0.40 mol NH3 and 0.40 mol HCl 0.20 mol HNO2 and 0.10 mol NaOH 0.20 mol HBr and 0.10 mol KOH My answer is that HNO2 and NaOH will...
April 8, 2012

Chemistry(Please check answer)
The solubility product expression for mercury(I) iodide, Hg2I2 is Ksp = ? My answer is [Hg2^2+^][2I^-^]^2^ Would you agree?
April 8, 2012

Chemistry(Please help)
What is the pH of a 5.06E-2 M aqueous solution of sodium acetate? I know that I would set this up the same way I did for the previous question that I posted. I am just confused on how to find the Ka. I know it is kw/kb but for what compound is what I do not know. Chemistry(...
April 8, 2012

Chemistry(Please help)
The solubility product expression for mercury(I) iodide, Hg2I2 is Ksp = ? My answer is [Hg2^2+^][2I^-^]^2^ Would you agree?
April 8, 2012

Chemistry(Please check answer)
most to least soluble. AgCl is more soluble than Ag2CO3 which is more soluble than Ag3PO4.
April 7, 2012

Chemistry(Please check answer)
The Ksp values for three salts are given: AgCl = 1.0e-10 Ag2CO3 = 6.3e-10 Ag3PO4 = 2.0e-21 Determine the order of solubility for these three salts. My answer is AgCl > Ag2CO3 > Ag3PO4. Would you agree? Thank you.
April 7, 2012

Chemistry(Please help)
I set this up as 5.55e-10 = x^2/0.0506-x After converting to pH I got 5.27 but it said that this was incorrect so maybe I do need to use a quadratic, but I am not sure how to go about this.
April 7, 2012

Chemistry(Please help)
So for Kb I did kw/ka = 1.0e-14/1.8e-5 = 5.55e-10 . Now I would multiply this by 5.06e-6 and take the square root and then covert to pH by taking the -log. Is this correct?
April 7, 2012

Chemistry(Please help)
so for Kb
April 7, 2012

Chemistry(Please help)
ok thank you!
April 7, 2012

Chemistry(Please help)
What is the pH of a 5.06E-2 M aqueous solution of sodium acetate? I know that I would set this up the same way I did for the previous question that I posted. I am just confused on how to find the Ka. I know it is kw/kb but for what compound is what I do not know.
April 7, 2012

Chemistry(Please help)
oh ok I get it, thank you!!
April 7, 2012

Chemistry(Please help)
For the Ka of NH4^+^ I did 1.0e-14/1.83-5 = 5.55e-10. What do I do with this value? So for (NH3)(H3O) / NH4 it would be x^2/0.144-x
April 7, 2012

Chemistry(Please help)
so the values for both NH3 and H3O are 0?
April 7, 2012

Chemistry(Please help)
What is the pH of 0.144M aqueous solution of ammonium nitrate? I am not sure what to do. Would I do 10^-0.144^ = 0.71?
April 7, 2012

Chemistry(Please respond, thank you)
oh ok I see, thank you.
April 7, 2012

Chemistry(Please respond, thank you)
The ionization constant of HA is 4.0e-4. Using the ice table what is the equilibrium concentration of HA in terms of its initial concentration and x? HA(aq) + H2O(l) = H3O^+^(aq) + A^-^(aq) I 0.040M OM OM C -X +x +x E ? x x I thought that to find the concentration you need to ...
April 7, 2012

Chemistry
Calculate the [H+] in a solution containing 1.00 M hydroflouris acid (Ka=7.2 x 10^-4) and .50 M sodium fluoride
April 6, 2012

Chemistry
.050 mole of weak acid (HA) is dissolved in enough water to make 1.0 L of solution. The pH of this solution is 3.50. What is the value of Ka for this weak acid?
April 6, 2012

Chemistry
SO I have to figure out what k1 is?
April 3, 2012

Chemistry
Find the pH of 1.0M Na2SO3(aq) solution at 25 degrees Celsius. I am not sure how to start this problem. I started off by doing 1.0M = x/1000 to get x=0.001 but I do not know if this is how to start.
April 3, 2012

Chemistry
Ok, thank you, I understand now.
April 3, 2012

Chemistry
2.5E-5 = (x)^2/1.75 So to solve for x i know I have to take the sqrt of both sides but first do I have to move the 1.75 to the left side?
April 3, 2012

Chemistry(Could someone please help)
Given the wage in dollar per day and the CPI for years 1 and 2 how do you calculate the nominal % increase in wage and the real % increase in wage? I am not sure what to do for this or what the formula is if any. Thank you for your help. I have tried to find websites that have...
April 2, 2012

Chemistry(Please check)
1) The Ka for acetic acid is 1.8e-5. What is the pH of a 3.18M solution of this acid? I did 1.8e-5 = x^2/3.18 x=sqrt 1.8e-5 X 3.18 = 7.56e-3 pH=-log(7.56e-3) = 2.12 The pH is 2.12 2) At 25 degrees celsius, the pH of a 1.75M NaCN solution (the Ka for HCN is 4.0e-10) is ? 4.0e-...
April 2, 2012

Chemistry(Thank you for your help)
What is the equilibrium constant for the reaction of ammonium ion with formate ion? I know that the ionization constant for ammonium ion is Ka=5.6e-10 and for formate Kb=5.6e-11. I am not sure what to do next. Should I divide ka by kb?
April 2, 2012

Chemistry(Please check)
Thank you!
April 1, 2012

Chemistry(Please check)
A 0.0170 M solution of an acid has a pH of 2.5. What is the pKa? i did 10^-2.5=3.16e-3 Then 0.0170 - 3.16e-3=0.01384 ka= (3.16e-3)^2 / 0.01384 = 7.21e-4 pKa = -log(7.21e-4) = 3.14 The pKa is 3.14 Would you agree?
April 1, 2012

General Science
What is the ohms if voltage is 24 and I is 6?
April 1, 2012

Chemistry(Please check)
Which of the following equations correspond to the Ka2 for phosphoric acid? note: the double equal sign (==) means equilibrium. a) HPO42- (aq) + H2O (l) == H3O+(aq) + PO43-(aq) b) PO43- (aq) + H2O (l) == HPO42-(aq) + OH–(aq) c) H3PO4 (aq) + H2O (l) == H3O+(aq) + H2PO4-(aq...
April 1, 2012

Chemistry(Please help)
What is the equilibrium constant for the reaction of ammonium ion with formate ion? I know that the ionization constant for ammonium ion is Ka=5.6e-10 and for formate Kb=5.6e-11. I am not sure what to do next. Should I divide ka by kb?
April 1, 2012

Chemistry
What is the equilibrium constant for the reaction of ammonium ion with formate ion? I know that the ionization constant for ammonium ion is Ka=5.6e-10 and for formate Kb=5.6e-11. I am not sure what to do next. Should I divide ka by kb?
April 1, 2012

Chemistry(Please check answers)
is 2.5e-5 my answer or do I have to do another step?
April 1, 2012

Chemistry(Please check answers)
so kb = 1.0e-14 / 4.0e-10 = 2.5e-5
April 1, 2012

Chemistry(Please check answers)
is Kw 1.0e-14?
April 1, 2012

Chemistry(Please check answers)
1) The Ka for acetic acid is 1.8e-5. What is the pH of a 3.18M solution of this acid? I did 1.8e-5 = x^2/3.18 x=sqrt 1.8e-5 X 3.18 = 7.56e-3 pH=-log(7.56e-3) = 2.12 The pH is 2.12 2) At 25 degrees celsius, the pH of a 1.75M NaCN solution (the Ka for HCN is 4.0e-10) is ? 4.0e-...
April 1, 2012

Life orientation
we will not just answer your homework questions. Give us some information to work with and then we can tell you if it is correct and add on to it
April 1, 2012

Chemistry(Please check)
So the lowest pH would be the acidic solution correct?
April 1, 2012

Chemistry(Please check)
Which 0.10M solution has the lowest pH? NaCl, KCN, LiF, RbClO, all have the same pH. I think that the answer is that they all have the same pH. Would you agree? Thank you!
April 1, 2012

Economics(Please help)
Given the wage in dollar per day and the CPI for years 1 and 2 how do you calculate the nominal % increase in wage and the real % increase in wage? I am not sure what to do for this or what the formula is if any. Thank you for your help.
April 1, 2012

Chemistry(Please respond, thank you)
Oh ok I got it now thank you.
April 1, 2012

Chemistry(Please respond, thank you)
What is the [H3O+] for a neutral solution at 50 degrees celsius? I know that kw=[H3O+][OH-] but I am not sure what to do to get the H3O. The value I have for kw=5.76e-14 and I have the pH 6.62 but I do not know what the OH would be. Chemistry(Please help, thank you) - DrBob222...
April 1, 2012

Chemistry(Please help, thank you)
I dont know if I put this in my calculator correctly but I got -0.82.
March 31, 2012

Chemistry(Please help, thank you)
so I would take the - log of 6.62?
March 31, 2012

Chemistry(Please help, thank you)
What is the [H3O+] for a neutral solution at 50 degrees celsius? I know that kw=[H3O+][OH-] but I am not sure what to do to get the H3O. The value I have for kw=5.76e-14 and I have the pH 6.62 but I do not know what the OH would be.
March 31, 2012

Economics(Please help)
Given the wage in dollar per day and the CPI for years 1 and 2 how do you calculate the nominal % increase in wage and the real % increase in wage? I am not sure what to do for this or what the formula is if any. Thank you for your help.
March 31, 2012

Economics(Please respond, thank you)
Given the wage in dollar per day and the CPI for years 1 and 2 how do you calculate the nominal % increase in wage and the real % increase in wage? I am not sure what to do for this or what the formula is if any. Thank you for your help.
March 30, 2012

Chemistry(Please check, thank you)
For an experiment on the effect of a buffer solution, I need to calculate the expected pH of the buffer. I know that I have to make an amounts table and use the Hasselbalch equation to find the pH. For the first part, 0.10M HCl was added to a buffer. The first addition was 5 ...
March 29, 2012

Organic Chemistry
I'm looking for a site with all the pentene isomers, and all the pentyne isomers. Anyone got any suggestions?
March 26, 2012

Chemistry
a) Write the chemical formula for the simplest pentyne isomer, b) give the name of the two isomers that have pentyne as the base chain, c) give the name of the one isomer that has butyne as the base chain, d) give the name of the 5 chain cyclic isomer, e) give the name of the ...
March 26, 2012

Chemistry
4 a) Write the chemical formula for the simplest pentene isomer, b) give the name of the two isomers that have pentene as the base chain, c) give the name of the three isomers that have butene as the base chain, d) give the name of the 5 chain cyclic isomer, e) give the name ...
March 26, 2012

Math
Mark wanted to measure the height of a nearby building. He placed a mirror on the pavement at point P, 80 feet from the base of the building. He then backed away until he saw an image on the top of the building in the mirror. If Mark is 6 feet tall, and he is standing 9 feet ...
March 26, 2012

Math
(4.44e-2 - x) (8.06e-2 - x) / (0.331 + 2x)^2 = 1.80e-2 I need to rearrange this equation so that I can get a,b, and c, for the quadratic equation but I am not sure how to do this. Thank you for the help. Math(Please answer, thank you) - bobpursley, Sunday, March 25, 2012 at 7:...
March 25, 2012

Math(Please answer, thank you)
So I have to multiply (4.44e-2 -x )(8.06e-2 - x) by (0.331 + 2x)^2 or am I suppose to multiply 1.80e-2 by it?
March 24, 2012

Math(Please answer, thank you)
(4.44e-2 - x) (8.06e-2 - x) / (0.331 + 2x)^2 = 1.80e-2 I need to rearrange this equation so that I can get a,b, and c, for the quadratic equation but I am not sure how to do this. Thank you for the help.
March 24, 2012

Chemistry
Determine the concentration in parts per million if 0.500 moles of NaCl are found in 35000g of a salt water solution. Okay, so I've done questions dealing with ppm and was able to work them out fine, but I can't seem to figure this one out. Any help you can give me ...
March 24, 2012

Chemistry(Please check)
Ok so the only one im still not sure about is CO3^2-^. The -2 are lone pairs so I guess it is both Lewis and BL.
March 24, 2012

Chemistry(Please check)
Oh Im sorry I missed that. CO3^2-^ is an answer listed. I was able to find that CN^-^ is a BL base but Im still not sure if it is a Lewis base. I do not think it is.
March 24, 2012

Chemistry(Please check)
1) Which statement below is correct (true)? a) Since HNO2 is a stronger acid than HF it must have a greater pKa. b) Since HOCℓ is a stronger acid than HCN, then OCℓ– is a stronger base than CN–. c) The dissociation (or ionization) of HOCℓ in water ...
March 24, 2012

Chemistry(Please check)
1) Which of the following is not amphiprotic? H20, NH4^+^, HSO4^-^, H2PO4^-^, all choices are amphiprotic. I think that all of these are amphiprotic. I know for sure that H20 and H2PO4^-^ are. 2) The ion HPO4^-^ has both a conjugate base as well as a conjugate acid. The ...
March 24, 2012

Chemistry(Please just check, thank you)
Ok thank you!
March 24, 2012

Chemistry(Please just check, thank you)
1) The approximate pH of a 3.0 X 10^-3 M solution of the strong acid H2SO4 is? I did pH= -log(3.0 X 10^-3) = 2.5 2)If HCLO2 is a stronger acid than HF, which is stronger than HOCL, then the order of strengths of the conjugate bases of these acids is? My answer is CLO2^-^ < ...
March 24, 2012

Chemistry
Write the chemical formula for the simplest heptane isomer and give its name, b) give the names of two heptane isomers with hexane as the base chain, c) give the names of names of the five heptane isomers with pentane as the base chain, d) give the name of the isomer with ...
March 24, 2012

Chemistry
What is the mass in kg of 20.0 L of diesel fuel? Assume the fuel has a density of 0.85 g/mL.
March 24, 2012

biology
C.
March 21, 2012

Chemistry
Thank you very much!
March 21, 2012

Pages: <<Prev | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | Next>>

Search
Members