Posts by hannah
Total # Posts: 3,482

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!!! 
Math(Please someone respond, very confused)
thank you I was looking for that post but couldn't find it. 
Math(Please someone respond, very confused)
The original equation was 1.7e3 = (0.0015 x)^2 / (0.025 +1/2x)(0.025 + 1/2x) Square root of both sides is 0.0412 = (0.0015x) / (0.025 + 1/2x) Solve for x and when I put in 0.001 or 1.0e3 it says that it is incorrect, I don't 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 1.7e3 = (0.0015x)^2 / (0.025 + 1/2x)(0.025 + 1/2x) 
Math(Please respond, thank you)
The original equation was 1.7e3 = (0.0015 x)^2 / (0.025 +1/2x)(0.025 + 1/2x) Square root of both sides is 0.0412 = (0.0015x) / (0.025 + 1/2x) Solve for x and when I put in 0.001 or 1.0e3 it says that it is incorrect, I don't 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 tshirts 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 tshirts 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 1.7e3 = (0.0015 x)^2 / (0.025 +1/2x)(0.025 + 1/2x) Square root of both sides is 0.0412 = (0.0015x) / (0.025 + 1/2x) Solve for x and when I put in 0.001 or 1.0e3 it says that it is incorrect, I don't 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 don't know why. 
Math(Please help)
do for x I got 6.63e4. 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 = 0.015x / 0.525x I am not sure where to go from here since there are two x's. 
political science/media
d. wire services 
Chemistry(Please respond, thank you!)
Using this data, 2 NO(g) + Cl2(g) == 2 NOCl(g) Kc = 3.20 X 103 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 ... 
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 ... 
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 ... 
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?