Posts by hannah
Total # Posts: 3,512

Chemistry(Please help)
so for kb I do 1e14/.15? 
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. 
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 and what are the functions? 
math
How many 2 quart pitchers could you fill with 512 fluid ounces of juice????? 
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 1.4e11 for F^^ and 7.2e4 for HF? Chemistry(Please help)  DrBob222, Tuesday, April 10, 2012 at 12:04am This is a buffer problem. pH = pKa + log(... 
Chemistry(Please check)
So it would be 27x^4, so I divide 5.0e33 by 27 to get 1.8e34 and then raise this to the 1/4 power which I got 4e9. 
Chemistry(Please check)
What is molar solubility of Al(OH)3 at 25 degrees C given the solubility product Ksp = 5.0e33? I set this up as Al^3+ + 3OH^ Ksp=[Al^3+][OH^]^3 5.0e33 = (x)(3x)^3 Before I go any further did I do this correctly? 
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/ 1.8e5 from acetic acid? 
Chemistry(Please help)
So it would be pH=4.74 + log base/acid and I use 7.2e4 for HF but after I convert g NaF in 150mL to M is this what I use for the base? 
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 1.4e11 for F^^ and 7.2e4 for HF? 
Chemistry(Please check)
. Ksp for Fe(IO3)3 is 1014. Two solutions, one being iron(III) nitrate and the other being sodium iodate, were mixed. At the instant of mixing, [Fe3+] = 104M and [IO3] = 105M. What happens? My answer is that a precipitate forms because Qsp > Ksp. Would you agree? ... 
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... 
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 ... 
Chemistry(Please help)
For the second way, where did the 2.29e5 come from? 
Chemistry(Please help)
For an acetic acidsodium 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 1.8e5 and that I have to divide this value by the value of sodium acetate but I do not understand how you get ... 
Chemistry(Please check answers)
1)What is the pH of a saturated solution of lead(II) hydroxide? The Ksp= 4.0e15 Pb(OH)2 4.0e15 = (x)(2x)^2 = 4x^3 I divided by 4 and took the cube root and got 1.12e5 but I am not sure I took the cube root correctly. log(1.12e5)= 4.95 144.95 = 9.05 The answer choices ... 
Chemistry(Please check)
. Ksp for Fe(IO3)3 is 1014. Two solutions, one being iron(III) nitrate and the other being sodium iodate, were mixed. At the instant of mixing, [Fe3+] = 104M and [IO3] = 105M. What happens? My answer is that a precipitate forms because Qsp > Ksp. Would you agree? 
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 ... 
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... 
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? 
Chemistry(Please help)
What is the pH of a 5.06E2 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(... 
Chemistry(Please help)
The solubility product expression for mercury(I) iodide, Hg2I2 is Ksp = ? My answer is [Hg2^2+^][2I^^]^2^ Would you agree? 
Chemistry(Please check answer)
most to least soluble. AgCl is more soluble than Ag2CO3 which is more soluble than Ag3PO4. 
Chemistry(Please check answer)
The Ksp values for three salts are given: AgCl = 1.0e10 Ag2CO3 = 6.3e10 Ag3PO4 = 2.0e21 Determine the order of solubility for these three salts. My answer is AgCl > Ag2CO3 > Ag3PO4. Would you agree? Thank you. 
Chemistry(Please help)
I set this up as 5.55e10 = x^2/0.0506x 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. 
Chemistry(Please help)
So for Kb I did kw/ka = 1.0e14/1.8e5 = 5.55e10 . Now I would multiply this by 5.06e6 and take the square root and then covert to pH by taking the log. Is this correct? 
Chemistry(Please help)
so for Kb 
Chemistry(Please help)
ok thank you! 
Chemistry(Please help)
What is the pH of a 5.06E2 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(Please help)
oh ok I get it, thank you!! 
Chemistry(Please help)
For the Ka of NH4^+^ I did 1.0e14/1.835 = 5.55e10. What do I do with this value? So for (NH3)(H3O) / NH4 it would be x^2/0.144x 
Chemistry(Please help)
so the values for both NH3 and H3O are 0? 
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? 
Chemistry(Please respond, thank you)
oh ok I see, thank you. 
Chemistry(Please respond, thank you)
The ionization constant of HA is 4.0e4. 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 ... 
Chemistry
Calculate the [H+] in a solution containing 1.00 M hydroflouris acid (Ka=7.2 x 10^4) and .50 M sodium fluoride 
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? 
english
correct^ 
Chemistry
SO I have to figure out what k1 is? 
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. 
Chemistry
Ok, thank you, I understand now. 
Chemistry
2.5E5 = (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? 
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... 
Chemistry(Please check)
1) The Ka for acetic acid is 1.8e5. What is the pH of a 3.18M solution of this acid? I did 1.8e5 = x^2/3.18 x=sqrt 1.8e5 X 3.18 = 7.56e3 pH=log(7.56e3) = 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 4.0e10) is ? 4.0e... 
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=5.6e10 and for formate Kb=5.6e11. I am not sure what to do next. Should I divide ka by kb? 
Chemistry(Please check)
Thank you! 
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=3.16e3 Then 0.0170  3.16e3=0.01384 ka= (3.16e3)^2 / 0.01384 = 7.21e4 pKa = log(7.21e4) = 3.14 The pKa is 3.14 Would you agree? 
General Science
What is the ohms if voltage is 24 and I is 6? 
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... 
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=5.6e10 and for formate Kb=5.6e11. I am not sure what to do next. Should I divide ka by kb? 
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=5.6e10 and for formate Kb=5.6e11. I am not sure what to do next. Should I divide ka by kb? 
Chemistry(Please check answers)
is 2.5e5 my answer or do I have to do another step? 
Chemistry(Please check answers)
so kb = 1.0e14 / 4.0e10 = 2.5e5 
Chemistry(Please check answers)
is Kw 1.0e14? 
Chemistry(Please check answers)
1) The Ka for acetic acid is 1.8e5. What is the pH of a 3.18M solution of this acid? I did 1.8e5 = x^2/3.18 x=sqrt 1.8e5 X 3.18 = 7.56e3 pH=log(7.56e3) = 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 4.0e10) is ? 4.0e... 
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 
Chemistry(Please check)
So the lowest pH would be the acidic solution correct? 
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! 
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. 
Chemistry(Please respond, thank you)
Oh ok I got it now thank you. 
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=5.76e14 and I have the pH 6.62 but I do not know what the OH would be. Chemistry(Please help, thank you)  DrBob222... 
Chemistry(Please help, thank you)
I don't know if I put this in my calculator correctly but I got 0.82. 
Chemistry(Please help, thank you)
so I would take the  log of 6.62? 
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=5.76e14 and I have the pH 6.62 but I do not know what the OH would be. 
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. 
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. 
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 ... 
Organic Chemistry
I'm looking for a site with all the pentene isomers, and all the pentyne isomers. Anyone got any suggestions? 
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 ... 
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 ... 
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 ... 
Math
(4.44e2  x) (8.06e2  x) / (0.331 + 2x)^2 = 1.80e2 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:... 
Math(Please answer, thank you)
So I have to multiply (4.44e2 x )(8.06e2  x) by (0.331 + 2x)^2 or am I suppose to multiply 1.80e2 by it? 
Math(Please answer, thank you)
(4.44e2  x) (8.06e2  x) / (0.331 + 2x)^2 = 1.80e2 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. 
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 ... 
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. 
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. 
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 ... 
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 ... 
Chemistry(Please just check, thank you)
Ok thank you! 
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^^ < ... 
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 ... 
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. 
biology
C. 
media
d. wire services 
Chemistry
Thank you very much! 
Chemistry
Consider the reaction: PCl3(g) + Cl2(g) PCl5(g). If [PCl3] = 0.78 M, [Cl2] = 0.44 M, and [PCl5] = 0.88 at equilibrium, what is the value of K? A.0.39 B.1.4 C.2.6 D.0.72 Thanks! 
Chemistry(Please check)
ok 
Chemistry(Please check)
For an experiment we had to test the equilibrium of BiCl3  BiOCl First I had to mix a small amount of BiCl3 with 2mL of water. After doing this the color was cloudy white. Then I added6.0M of HCl dropwise in which the color became clear. Then 25mL was added and the color ... 
statistics
The average score on a science test was 72 with a standard deviation of 6. The average score on a history test was 89 with a standard deviation of 7. Compare the variability of the two classes. 
Chemistry(Please respond, thank you)
I think that's why Im so confused because when added the HCl it only turned dark yellow and then our tube with the NaOH didn't even change. Ok so I see why it would shift to the left but im not sure what it was reacting with. From the equation the CrO4^2^ is on the ... 
Chemistry(Please respond, thank you)
oh ok I have to include in my answer if the process is exo or endothermic but I am not sure how I am suppose to know that. We then had to add 1 drop of 1.0M NaOh to a new test tube with 2.5mL of Na2CrO4 in it. I guess the color change was suppose to be orange even though my ... 
Chemistry(Please respond, thank you)
Also the next question was which chromium ion is orange and which is yellow ans how do you know. So the dichromate is yellow and the Cr207^2^ is yellow correct?? 
Chemistry(Please respond, thank you)
Ok so when the HCl is added it shifts to the right which is an exothermic process correct? It shifted to the right because the reactant is being used up?? 
Chemistry(Please respond, thank you)
For an experiment I had to add 1 drop of 1.0M HCl into a test tube that had 2.5mL of 0.10M Na2CrO4 and record the color. The original color of the Na2CrO4 was yellow. After adding the HCl the color became a very dark yellow. I know that the equilibrium shifted shifted to the ... 
Algebra 2
Factor 12^23 
chemistry
In the 1970s, when lead was widely used in "ethyl" gasoline, the blood level of the average American contained 0.25 ppm lead. The danger level of lead poisoning is 0.80 ppm. (a) What percent of the average person was lead? (b) How much lead would be in an average 80 ... 
Math(Please check)
thank you for your help 
Math(Please check)
2.5 X 10^(3) = (.28)(.38) / x^2 Solve for x. 2.5 X 10^(3) = 0.1064 / x^2 2.5 X 10^(3) X 0.1064 = 266 sqrt 266 = 16.3 Did I do this correctly?? Thank you for your help. 
Math(Please someone respond, very confused)
ok thank you!!!