Tuesday
July 22, 2014

Posts by hannah


Total # Posts: 2,828

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=5.6e-10 and for formate Kb=5.6e-11. 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=5.6e-10 and for formate Kb=5.6e-11. I am not sure what to do next. Should I divide ka by kb?

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

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

Chemistry(Please check answers)
is Kw 1.0e-14?

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-1...

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=5.76e-14 and I have the pH 6.62 but I do not know what the OH would be. Chemistry(Please help, thank you) - DrBob222...

Chemistry(Please help, thank you)
I dont 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=5.76e-14 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 m...

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 o...

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 f...

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:...

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?

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.

Math
Please disregard.

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 wou...

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 i...

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 conjug...

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 buta...

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.

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 drop-wise in which the color became clear. Then 25mL was added and the color wa...

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 thats why Im so confused because when added the HCl it only turned dark yellow and then our tube with the NaOH didnt 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 left side so...

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 co...

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 l...

Algebra 2
Factor 12^2-3

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!!!

Math(Please someone respond, very confused)
thank you I was looking for that post but couldnt find it.

Math(Please someone respond, very confused)
The original equation was 1.7e-3 = (0.0015 -x)^2 / (0.025 +1/2x)(0.025 + 1/2x) Square root of both sides is 0.0412 = (0.0015-x) / (0.025 + 1/2x) Solve for x and when I put in -0.001 or 1.0e-3 it says that it is incorrect, I dont know why??

Math(Please respond, thank you)
yes , it is 10^(-3). I sorry,im just so confused. I am typing it exactly as it is shown on my homework. They used().

Math(Please respond, thank you)
The equation is written as 1.7e-3 = (0.0015-x)^2 / (0.025 + 1/2x)(0.025 + 1/2x)

Math(Please respond, thank you)
The original equation was 1.7e-3 = (0.0015 -x)^2 / (0.025 +1/2x)(0.025 + 1/2x) Square root of both sides is 0.0412 = (0.0015-x) / (0.025 + 1/2x) Solve for x and when I put in -0.001 or 1.0e-3 it says that it is incorrect, I dont know why??

Ecomonics(Urgent,please respond)
The table below shows the market basket quantities and prices for the base year (year 1) Base year 1 Price in price Quantity base year yr 2 Product Pizza 15 $3 $3.75 t-shirts 4 $10 $9 rent 1 $500 $550 In year 1 the CPI was? In year 2 the CPI was? I know that cpi= (expenditures...

Economics(Please respond, thank you)
The table below shows the market basket quantities and prices for the base year (year 1) Base year 1 Price in price Quantity base year yr 2 Product Pizza 15 $3 $3.75 t-shirts 4 $10 $9 rent 1 $500 $550 In year 1 the CPI was? In year 2 the CPI was? I know that cpi= (expenditures...

Chemistry
Pure water boils at 100ºC (212ºF). When a substance is added to the water the boiling point increases due to what is referred to as the boiling point elevation. (a) What is the molecular mass of sucrose (C₁₂H₂₂O₁₁)? (b) If you add ...

Math(Please help)
The original equation was 1.7e-3 = (0.0015 -x)^2 / (0.025 +1/2x)(0.025 + 1/2x) Square root of both sides is 0.0412 = (0.0015-x) / (0.025 + 1/2x) Solve for x and when I put in -0.001 or 1.0e-3 it says that it is incorrect, I dont know why??

Math(Please help)
ok I tryed that to and for some reason it still says its wrong

Math(Please help)
yes its .0015 im sorry for the mistake, so it would be .0397=-40x +.5??

Math(Please help)
How did you get 39.5x?

Math(Please help)
For soem reason when I enter this answer on my online homework it says that its incorrect, I dont know why.

Math(Please help)
do for x I got 6.63e-4. Would you agree? Thank you for your help!!

Math(Please help)
oh ok and you got .0262 by subtracting 0.015 from 0.0412??

Math(Please help)
where did you get the 40x from??

Math(Please help)
0.0412 = 0.0015 - x / 0.025 + 1/2x Solve for x. 0.0412 = 0.015-x / 0.525x I am not sure where to go from here since there are two x's.

Chemistry(Please respond, thank you!)
Using this data, 2 NO(g) + Cl2(g) == 2 NOCl(g) Kc = 3.20 X 10-3 NO2(g) == NO(g) + ½ O2(g) Kc = 3.93 calculate a value for Kc for the reaction, NOCl (g) + ½ O2 (g) == NO2 (g) + ½ Cl2 (g) So I understand that 2NO + Cl2 + 1/2O2 = NO2 + 1/2 Cl2 but I do not un...

Chemistry(Please respond)
A study of the system, H2(g) + I2(g) == 2 HI(g), was carried out. Kc = 54.9 at 699.0 K (Kelvin) for this reaction. A system was charged with 2.50 moles of HI in a 5.00 liter vessel as the only component initially. The system was brought up to 699.0 K and allowed to reach equi...

Chemistry(Please respond, thank you!)
ok so 6.66(473K)(0.08206) = 258.5 which would be 2.59 which is one of the answer choices. Does this seem correct??

Chemistry(Please respond, thank you!)
For the system CaO(s) + CO2(g) = CaCO3(s), I added 1.00 mol of CaO(s) to 1.00L of 0.500M CO2(g) at 200 oC. At equilibrium the [CO2] = 0.150M. What is the value of Kp for this reaction? Kp would = CaCO3/(CaO)(CO2) I do not know what to do with the 0.500M and 1.00mol. Chemistry...

Chemistry - Please Check!
Thank you.

Chemistry - Please Check!
mZnS = 0.018 x 97.47 g/mol mZnS = 1.71 g I am pretty positive the first part of is right but, if my final answer is wrong again, could you explain the question for me?

Chemistry - Please Check!
Determine the mass of zinc sulphide, ZnS, produced when 6.2g of zinc and 4.5g of sulphur are reacted. Equation given: Zn + S8 >> ZnS Balanced equation: 8Zn + S8 >> 8ZnS nZn= 6.2 g/ (65.39 g/mol) = 0.095 mol nS8= 4.5 g/(256.48 g/mol) = 0.018 mol nS8 = 0.095 mol Zn x...

Chemistry(Please respond)
Well Na ions were added so would that still shift to the left? How do you know if it's endo or exothermic I have to include that in my answer?

Chemistry(Please respond)
I did an experiment to study the effects of changes in conditions on an equilibrium system. The first system was the dissociation of acetic acid. HC2H3O2 -> H^+^ + C2H3O2^-^ <- We had to add 2mL of acetic acid into a test tube and we had to test the pH of the solution an...

Chemistry(Please help)
For the reaction, 2 SO2(g) + O2(g) == 2 SO3(g), at 450.0 K (Kelvin) the equilibrium constant, Kc, has a value of 4.62. A system was charged to give these initial concentrations, (SO3) = 0.254 M and (O2) = 0.00855 M, and (SO2) = 0.500 M. In which direction will it go? I think I...

Chemistry(Please help)
So I did 1/0.150 and got 6.66 so now I use this with RT. I am not sure what R is?

Chemistry(Please help)
For the system CaO(s) + CO2(g) = CaCO3(s), I added 1.00 mol of CaO(s) to 1.00L of 0.500M CO2(g) at 200 oC. At equilibrium the [CO2] = 0.150M. What is the value of Kp for this reaction? Kp would = CaCO3/(CaO)(CO2) I do not know what to do with the 0.500M and 1.00mol.

Chemistry(Please help, thank you!)
I am familiar with how to do the ICE table but I am not sure how to set one up for this question with the 2.5 moles.

Chemistry(Please help, thank you!)
A study of the system, H2(g) + I2(g) == 2 HI(g), was carried out. Kc = 54.9 at 699.0 K (Kelvin) for this reaction. A system was charged with 2.50 moles of HI in a 5.00 liter vessel as the only component initially. The system was brought up to 699.0 K and allowed to reach equil...

Chemistry(Please help, thank you!)
So am I suppose to use the Kc values that are given??

Chemistry(Please help, thank you!)
Using this data, 2 NO(g) + Cl2(g) == 2 NOCl(g) Kc = 3.20 X 10-3 NO2(g) == NO(g) + ½ O2(g) Kc = 3.93 calculate a value for Kc for the reaction, NOCl (g) + ½ O2 (g) == NO2 (g) + ½ Cl2 (g) I do not understnad how I am suppose to use the Kc values given if the...

Chemistry(Please check answer)
I do not understand why do you 1/54.9??

Chemistry(Please check answer)
The equilibrium constant for the reaction, H2(g) + I2(g) == 2 HI(g) is 54.9 at 699.0 K (Kelvin). What is the equilibrium constant for 4 HI(g) == 2 H2(g) + 2 I2(g) under the same conditions? Note: the == indicates the equilibrium double arrow Since the second equation is double...

Chemistry(Urgent, please respond, thanks!!)
Thank you!!

Chemistry(Urgent, please respond, thanks!!)
1) For the reaction system, 2 SO2(g) + O2(g) = 2 SO3(g), Kc has a value of 4.62 at 450.0 K (Kelvin). A system, at equilibrium has the following concentrations: (SO3) = 0.254 M; (O2) = 0.00855 M. What is the equilibrium concentration of SO2? Is set this up as 4.62=(SO3)^2 / (SO...

math
i don't know. thats what i'm asking you

Astronomy
what are the largest stars in the HR diagram called?

Chemistry(Can someone please answer!!)
The decomposition of hydrogen peroxide in the presence of potassium iodide is believed to occur by the following mechanism: step 1 slow: H2O2 + I^- = H2O + OI^- step 2 fast: H2O2 + OI^- = H2O + O2 + I^- 1) What is the equation for the overall reaction? Use the smallest intege...

Math(Can someone please answer!!)
Thank you!!!

Math(Can someone please answer!!)
ln [2.30E-2] = ln(0.102) - (k s-1)(2360 s) k = 6.31E-4 s -1 I did 2360k = 1n(0.102 * 0.023) 2360k = -6.055 then I divided 2360 by -6.055 but I didnt get 6.31e-4. Where did I mess up???

Math(Can someone please answer!!)
n [1.70E-2] = ln(0.144) - (k s-1)(3609 s) Solve for k. I have a TI30 calculator. Am I suppose to press just the ln button or do I have to press 2nd and then ln??

Math
ln [1.70E-2] = ln(0.144) - (k s-1)(3609 s) Solve for k. I have a TI30 calculator. Am I suppose to press just the ln button or do I have to press 2nd and then ln??

Chemistry
The decomposition of hydrogen peroxide in the presence of potassium iodide is believed to occur by the following mechanism: step 1 slow: H2O2 + I^- = H2O + OI^- step 2 fast: H2O2 + OI^- = H2O + O2 + I^- 1) What is the equation for the overall reaction? Use the smallest intege...

Chemistry
The decomposition of hydrogen peroxide in the presence of potassium iodide is believed to occur by the following mechanism: step 1 slow: H2O2 + I^- = H2O + OI^- step 2 fast: H2O2 + OI^- = H2O + O2 + I^- 1) What is the equation for the overall reaction? Use the smallest intege...

Chemistry
1/[N2O] = 1/(1.75M) + (1.10E-3M^-1 S^-1)(1852s) [N2O] = 0.383 M I know I posted a similar question but I am having trouble with this one as well. Should I do 1/1.75 first and then add 1.10e-3 and then multiply by 1852? Math(Thank you for your help) - john, Friday, March 9, 20...

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