# Posts by hannah

Total # Posts: 3,512

1. ### Math(Please someone respond, very confused)

thank you I was looking for that post but couldn't find it.
2. ### 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 don't know why??
3. ### 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().
4. ### 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)
5. ### 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 don't know why??

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...
7. ### 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...
8. ### 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 ...

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 don't know why??

ok I tryed that to and for some reason it still says its wrong

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

How did you get 39.5x?

For soem reason when I enter this answer on my online homework it says that its incorrect, I don't know why.

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

oh ok and you got .0262 by subtracting 0.015 from 0.0412??

where did you get the 40x from??

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.
18. ### political science/media

d. wire services
19. ### 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 ...

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 ...
21. ### 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??
22. ### 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...

Thank you.
24. ### 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?
25. ### 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...

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?

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 ...

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...

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

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.

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.

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 ...

So am I suppose to use the Kc values that are given??

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 ...

I do not understand why do you 1/54.9??

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 ...

Thank you!!
38. ### 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 / (...
39. ### math

i don't know. that's what i'm asking you
40. ### Astronomy

what are the largest stars in the HR diagram called?

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 ...

Thank you!!!

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 didn't get 6.31e-4. Where did I mess up???

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??
45. ### 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??
46. ### 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 ...
47. ### 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 ...
48. ### 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, ...

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 integer...

Disregard question. I figured it out!

If you are given the slope and y intercept how do you find the rate constant of a chemical equation??? Would I multiply the slope and the y intercept???
52. ### Math(Thank you for your help)

So first I did multiplication (1.10e-3)(1852) and then divided 1/1.75 and then added and I cant get the answer.
53. ### Math(Thank you for your help)

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?
54. ### Chemistry(Thank you for your help!)

O ok I didn't know it was that easy!!! Thank you!
55. ### Chemistry(Thank you for your help!)

The following info was obtained: [HI], M 0.535 0.268 0.134 6.70E-2 seconds 0 520 781 911 What is the average rate of disappearance of HI from t = 0 s to t = 520 s The answer is 5.13E-4 M s-1 but I do not understand how to get this!!!Could someone please explain!! Thank you!!

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?

Ok how did you get 5.56e-3???

If the time elapsed is 4.26 min, what is the value of the rate constant, k? ln[R]t / [R]o = -0.0237 I am not sure how to slove this. Would I do ln 4.26 minutes times -0.0237???

ok thank you so much!!!

ln [5.01E-3] = ln(4.86E-2) - (1.80E-2s-1)(t s) Solve for t. t = 126 s First I did 4.86e-2 - 1.80e-2 and then on my calculator I pressed the 2nd button and then ln and got 1.031. Then I did the same thing to get the ln of 5.01e-3 and divided that by 1.031 but did not get 126 as...
61. ### Math

yes that's what it means and how I posted it is exactly how it is written on my homework but I just cant seem to get that answer.
62. ### Math

ln [5.01E-3] = ln(4.86E-2) - (1.80E-2s-1)(t s) Solve for t. t = 126 s First I did 4.86e-2 - 1.80e-2 and then on my calculator I pressed the 2nd button and then ln and got 1.031. Then I did the same thing to get the ln of 5.01e-3 and divided that by 1.031 but did not get 126 as...
63. ### Math

If the time elapsed is 4.26 min, what is the value of the rate constant, k? ln[R]t / [R]o = -0.0237 I am not sure how to slove this. Would I do ln 4.26 min X -0.0237?

If the time elapsed is 4.26 min, what is the value of the rate constant, k? ln[R]t / [R]o = -0.0237 I am not sure how to slove this. Is Rt 4.26 min
65. ### Chemistry (stoichiometry)

18.5 grams of calcium chloride reacts with 25.7 grams of sodium phosphate and produces calcium phosphate and sodium chloride. What is the limiting reactant? (show work)

If the time elapsed is 4.26 min, what is the value of the rate constant, k? ln[R]t / [R]o = -0.0237 I am not sure how to slove this. Is Rt 4.26 min?
67. ### Chemistry

I need to calculate the valueof Kc for 5 test tubes for an experiment that I completed on determination of Kc. The equation used was Fe^3+ + SCN^-= FeSCN^2+ After creating an ice table for the first test tube my values for Fe and SCN were 6.5e-4M and for FeSCN I got 5.7e-5M. ...

I need to calculate the valueof Kc for 5 test tubes for an experiment that I completed on determination of Kc. The equation used was Fe^3+ + SCN^-= FeSCN^2+ After creating an ice table for the first test tube my values for Fe and SCN were 6.5e-4M and for FeSCN I got 5.7e-5M. ...

Nevermind I know what I did wrong. I had to divide my final answer by 1000 to get kJ.

I did -1.23e4 / 8.314 = -1479.43 and I tryed 1.23e4 / 8.314 = 1479.43 but my online homework keeps saying that its incorrect.

I had to make a graph using lnK vs 1/T and find the slope. The slope was -1.23e4 and now I have to find Ea. Do I divide the slope by R
72. ### Chemistry

If the time elapsed is 4.26 min, what is the value of the rate constant, k? ln[R]t / [R]o = -0.0237 I am not sure how to slove this. Is Rt 4.26 min?
73. ### Chemistry

I had to make a graph using lnK vs 1/T and find the slope. The slope was -1.23e4 and now I have to find Ea. Do I divide the slope by R?

Right so for Fe I did (0.005M) (1.0mL Fe) / (7.0mL total of solutions in the tube) = 7.1e-4. So then my ICE table would say 7.10e-4 for both Fe and SCN because SCN for tube 1 had the same amounts and then I would subtract 7.1e-4 by the concentration of product which was 5.7e-5...

Oh I see that's the total of SCN and Fe but we also used 0.1M HNO3 so for the first test time we used 5mL of HNO3 with the Fe, SCN so the total would be 7mL. Fe= (0.005M) (1.0mL) = x(7mL) = 0.000714 So 7.1 e-4 Correct. The teacher said to put the answer in 2 sig figs.

Where did the 2mL come from?

I think I know where I made a mistake. For the initial concentrations of reactants Fe and SCN it says that I can use the table that was provided to determine how much the total volume of each solution was used. The table that was provided provided the amount of Fe and SCN used...

I completed a lab to find the determination of Kc. I have to find the concentrations of reactants at equilibrium using an ICE table. The equation that were are using is Fe^3+(aq) + SCN^-(aq) -> Fe(SCN)^2+(aq) I have to create 5 ICE tables because we used 5 different test ...
79. ### Calculus

Find the orthoganal trajectories of the family. Use a graphing utility to graph several members of each family. y = Ce^x What am I supposed to do here? Can someone point me in the right direction?
80. ### Chemistry

If the charge to mass ratio of a proton is 9.58 x 10^7 coulomb/kilogram and the charge is 1.60 x10^-19 coulomb, what is the mass of the proton?

So besides the weird number I got I'm guessing that I set it up correctly.

I put it in my calculator as 1.0 - 5.7 X e-5 and got 0.999943 I don't know why?

I completed a lab to find the determination of Kc. I have to find the concentrations of reactants at equilibrium using an ICE table. The equation that were are using is Fe^3+(aq) + SCN^-(aq) -> Fe(SCN)^2+(aq) I have to create 5 ICE tables because we used 5 different test ...
84. ### Chemistry(Please check, thank you!)

I completed a lab to find the determination of Kc. I have to find the concentrations of reactants at equilibrium using an ICE table. The equation that were are using is Fe^3+(aq) + SCN^-(aq) -> Fe(SCN)^2+(aq) I have to create 5 ICE tables because we used 5 different test ...

so then 4.
86. ### Chemistry

To balance the equation would I add a 2 in front of the O2?
87. ### Chemistry

For the reaction system, 2 H2O(g) + O2(g) == 2 H2O2 (g), the equilibrium concentrations are (H2O2) = 0.120 M; (H2O) = 0.860 M; (O2) = 0.330 M. Calculate the value of Kc for this reaction. A. 0.423 B. 0.872 C. 0.0590 D. 1.31 E. 2.51 I did 0.120 / 0.860 X 0.330 = 4.4228 = 4.23...
88. ### Chemistry

The reaction, 2 SO3(g) == 2 SO2(g) + O2(g) is endothermic. Predict what will happen if the temperature is increased. A. the pressure decreases B. more SO3(g) is produced C. Kc increases D. Kc decreases E. none of the above I chose that Kc will increase. Would you agree?

Oh wow I didn't even realize that they were both solids, I understand thank you!!

The equilibrium constant, Kc for the system, CaO(s) + CO2(g) == CaCO3(s), is A. Kc = (CaO) (CO2) / (CaCO3) B. Kc = (CO2) C. Kc = (CaCO3)/(CaO) D. Kc = (CaCO3) / (CaO) (CO2) E. Kc = 1 / (CO2) My answer is (CaCo3) / (CaO)(CO2). Would you agree?

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? A. to the...
92. ### Math

Disregard question. I figured it out. You take the ln of -2.035 and then multiply by 2.34 to get k2.
93. ### Math

ln k2/2.34 = -103,000J/8.314J/Kol[1/339K - 1/359K] ln k2/2.34 = -2.035941063 I am not sure what to do now!!

For my online homework when I put the answer in it keeps saying its wrong and says k[reactant 1]^order1 [reactant 2]^order2 but I thought I did this.

2NO(g) + Br2(g) -> 2NOBr(g) What is the rate equation? My answer is k[NO]2[Br2] Is this correct? Thank you!!!!

ok thank you!!