Number of results: 57,293
Posted by STACY on Monday, December 13, 2010 at 7:56pm. Consider an aqueous solution prepared from 250.0 mL of water and 1.27 g of potassium bromide. Express the amount of potassium bromide in this solution in terms of (a) mass percent (b) mole fraction (c) molarity assume the...
December 14, 2010 by STACY
A 0.327 g sample of a mixture of NaOH(s) and NaCl(s) requires 31.5 mL of 0.150 M HCl(aq) to react with all the NaOH(s). What is the mass percentage of the NaOH(s) in the mixture?
November 14, 2014 by Lexie
Chemistry urgent for my LAB today (22.09.11)
0.250g of phthalic acid is dissolved in 40.00cm^3 of 0.100 mol dm^-3 NaOH. It requires 11.80 cubic centimeters of 0.100 mol\dm^-3 HCL fo neutralisation( to phenolphthalein) The mole ratio in which phthalic acid reacts with sodium hydroxide ihn 1:2 (a) Calculate the moles of ...
September 21, 2011 by Petty
A 0.1 molal solution of a weak monoprotic acid was found to depress the freezing point of water 0.1930C. Determine the Ka of the acid. You can assume 0.1 molal and 0.1 molar are equivalent. 100 ml of a 0.1M solution of the above acid is titrated with 0.1 M NaOH. After an ...
February 12, 2012 by ashley
Lab: Determining Ka of Acetic Acid Purpose: The purpose of this experiment is to determine the molar concentration of a sample of acetic acid and to calculate its Ka. Materials: 25 mL pipet and bulb burette 2x150 mL beaker 125 mL Erlenmeyer flask acetic acid solution sodium ...
April 5, 2008 by Tim's Titration Lab
"The osmotic pressure of a saturated solution of strontium sulfate at 25C is 21 torr. What is the solubility product of this salt at 25C (Hint: calculate molarity from the colligative properties eqn of osmotic pressure and use it in the equilibrium expression" I converted torr...
March 17, 2010 by Kiki
This soidum hydroxide solution was then used to determine the amount of acetic acid in vinegar. Three titrations of the sodium hydroxide solution against exactly 5mL of vinegar using phenolphthalein indicator required 22.85Ml, 22.67mL and 22.93mL of the sodium hydroxide ...
November 25, 2012 by Elizabeth
You dissolve 6.55 g of potassium nitrate in enough water to make a 250. ML solution. 1.What is the molarity of this solution?answer:0.0262 2.If you took out 15.0 mL of this solution, how many moles of potassium nitrate would you have?answer:0.393 3. What is the percent (m/v) ...
April 23, 2012 by cateye
When 50.0mL of 1.20 M of HCl (aq)is combined with 50.0mL of 1.30 M of NaOH (aq) in a coffee-cup calorimeter, the temperature of the solution increases by 8.01 Degrees C. What is the change in enthalpy for this balanced reaction? HCl(aq) + NaOH(aq) --yields-- NaCl(aq) + H20(l) ...
November 14, 2012 by marcus
CHEMISTRY FOR DR. BOB or anyone else
A hypothetical weak acid HA, was combined with NaOH in the following proportions: 0.20 mol HA, 0.08 mol NaOH. The mixture was then diluted to a total volume of 1L, and the pH measured. (a) If pH=4.80, what is the pKa of the acid (b) how many additional moles of NaOH should be ...
May 11, 2007 by Delli
Chem - Molarity
Hi, I have this question related to Molarity and hoping you can help? The question says: 50.0 gram sample of NaCl is added to water to create a 0.50 L solution. What volume of this solution is needed to create a 1.30 L solution that is 0.100 M NaCl? It says also "Choose the ...
April 22, 2015 by Cassandra
General Chem lab
Hi, how do I calculate how many grams of unknown diprotic acid are needed to make 150mL of 0.750N (normal) solution? and to make 125mL of 0.500M (molar) solution? we have 0.5000M of NaOH.. Please help me...
October 30, 2011 by Ashley
I have had this question in my homework, and honestly I got stuck in these questions. I managed to convert 5.3g of Na2CO3 into moles, but then I got stuck and do not know what to do next to solve the question. If anyone knows how to work this out, help from anyone is greatly ...
September 29, 2012 by Matthias
A dilute solution of hydrochloric acid with a mass of 614.86 g and containing 0.33004 mol of HCl was exactly neutralized in a calorimeter by the sodium hydroxide in 619.41 g of a comparably dilute solution. The temperature increased from 15.529 to 19.691°C. The specific heat ...
July 1, 2014 by Sarah
A solution of HClO4 was standardized by dissolving 0.4125 g of primary standard grade HgO ina solution of KBR: HgO (s) + 4Br- + H2O → HgBr4 + 2OH- The liberated OH- consumed 46.51 mL of the acid. calculate the molarity of the HClO4
August 27, 2014 by nthabi
Given the thermochemical equation below, calculate the amount of energy released when 250. g of NaOH (molar mass = 40.0 g/mol) reacts with an excess of HCl. Report answer to the correct number of significant figures in units of kilojoules, kJ. NaOH + HCl --> NaCl + H2O ...
April 25, 2013 by sarah
Determine the molarity of a 15.0 % by mass Hydrogen Peroxide solution. The density of Hydrogen Peroxide is 1.054 g/mL. The 15.0% by mass can be broken apart into 15.0 g Hydrogen Peroxide and 100.0 g solution. Use the density of Hydrogen Peroxide solution (1.054 g/mL) to ...
February 1, 2015 by Jenna
A 50.0 mL sample of 0.12 M formic acid, HCOOH, a weak monoprotic acid, is titrated with 0.12 M NaOH. Calculate the pH at the following points in the titration. Ka of HCOOH = 1.8 multiplied by 10-4. What is the pH when 50.0 mL NaOH is added 60.0 mL NaOH is added 70.0 mL NaOH is...
April 3, 2011 by George
a. A 0.1 molal solution of a weak monoprotic acid was found to depress the freezing point of water 0.1930C. Determine the Ka of the acid. You can assume 0.1 molal and 0.1 molar are equivalent. b. 100 ml of a 0.1M solution of the above acid is titrated with 0.1 M NaOH. After an...
February 12, 2012 by billy
Acetic acid (HOAc) is a weak acid with a Ka= 1.8 X 10^-5 and sodium hydroxide (NaOH) is a strong base. What is the pH of a solution made by mixing 75.0 ml of a 0.160 M solution NaOH and 25.0 ml of a 0.640 M solution of HOAc? I got a pH of 5.22, but I am not sure if this is ...
May 12, 2009 by Chelsea
A.Determine the pH of the solution. a solution that is 1.17% HCl by mass (Assume a density of 1.01 g/mL for the solution.) B. Amphetamine (C9H13N) is a weak base with a pKb of 4.2. Calculate the pH of a solution containing an amphetamine concentration of 279 mg/L.
July 3, 2012 by Anonymous
Hello, im having major issues with this problem...A 100.0-mL solution of 0.017 M CH3COOH (Ka = 1.8 10-5) is titrated with 0.025 M NaOH. Now, I've gotten some the answers all ready (right answers have *)....but three of them are wrong, can someone tell me what to do? 1.) ...
October 12, 2011 by A person
A stock solution was prepared by dissolving exactly 0.4000 g of pure ASA (180.16g/mol) in 10.00 mL of NaOH and heating the solution to a gentle boil. After cooling to room temperature, the solution was poured into a 250 ml volumetric flask and diluted to the mark with DI water...
February 3, 2008 by Anonymous
A standard solution is prepared for the analysis of fluoxymesterone (C20H29FO3), an anabolic steroid. A stock solution is first prepared by dissolving 10.0 mg of fluoxymestrone in enough water to give a total volume of 500.0 ml. A 100.0 micro liter aliquot (portion)of this ...
December 7, 2011 by Lindsay
Help with lab report Need Help finishing my lab report.KNOWN VALUES ARE V OF HCL=50ML,M=2.188.V OF NAOH=55.3ML,M=2.088.INTIAL TEMP FOR HCL=22.5C,NAOH IS 23C.this is for part A: Mass of final NACL solution assuming that the density of a 1 M Nacl solution is 1.04 g/ml? Heat ...
October 26, 2012 by randy
If 31.00 mL of a dilute solution of lime water (calcium hydroxide) required 10.10 mL of 0.246 M hydrochloric acid solution for neutralization to a methyl red end point, calculate the molarity of the lime water. Can you please explain how to do it? Do I use M1V1=M2V2?
April 2, 2011 by Lara
A 100.0 ml sample of 0.300 M NaOH is mixed with a 100.0 ml sample of 0.300 M HNO3 in a coffee cup calorimeter. Both solutions were initially at 35.0 degrees celcius; the temperature of the resulting solution was recorded at 37.0 degrees celcius. Determine the delta H (in units...
July 12, 2012 by jen
I'm having a lot of trouble with a simple problem. I have a 3.0% by man solution of H2O2 in H2O. The density of thr solution is 1.0 g/mL. I need to find the molarity. How do I do this? So far I have: 3.0g H2O2 x 1 mol/34.02 g= .0881 mol I'm not sure where to go or what to do ...
March 23, 2007 by Christopher
When 2.53 g of NaOH(s)(40.0g/mol) dissolves in 100.0 g of water, the temperature of the solution changes from 20 degrees C to 26.3 degrees C. Calculate qrx in KJ/mol specific heat of the solution is 4.18 J/(g*K)
October 27, 2010 by Tara
we have to make an instrctinal packet showin relationships between moles and concentration. i cant find the following 1)how is the number of moles dissolved in a set amount of solvent related to the molarity? 2)how to determine the amount of solvent in 100, 125, 200, and 375 ...
February 12, 2009 by lyne
Dye of iodine is prepared by dissolving in ethanol , and 1% ( one percent ) of this solution contains 10 g of solute in 1000 g of solution 1) how many grams of solvent is there in the solution ? 2) how many moles of solute ( I2) is there? 3) what is the molality of 1% of this ...
July 12, 2014 by MAD
Please show work. 2Al(s) + 2NaOH(aq) + 6H2O(l) ---> 2NaAl(OH)4(aq) + 3H2(g) What mass of hydrogen gas would be formed from a reaction of 2.48 g Al and 4.76 g NaOH in water? Pb(NO3)2(s) + 2NaI(aq) ----> 2PbI2(s) +2NaNo3(aq) (a) If the solution contains 7.00 g NaI, what ...
February 25, 2013 by Anonymous
DrBob222 : need help with the problem
An unknown compound, X, is though to have a carboxyl group with a pKa of 2.0 and another ionizable group with a pKa between 5 and 8. When 75 mL of 0.1M NaOH is added to 100 mL of a 0.1M solution of X at pH 2.0, the pH increases to 6.72. Calculate the pKa of the second ...
September 11, 2012 by ron
Hello, im having major issues with this problem...I need to find a pH for a 100.0-mL solution of 0.017 M CH3COOH (Ka = 1.8 10-5) is titrated with 0.025 M NaOH. Now, I've gotten some the answers all ready (right answers have *)....but three of them are wrong, can someone tell ...
October 12, 2011 by A person
calculate the change in pH when 9.00ml of 0.100M HCl(aq) is added to 100.0mL of a buffer solution that is 0.100M in NH3(aq) and 0.100M NH4Cl(aq). ...Calculate the change in pH when 9.00,L if 0.100M NaOH(aq) is added to the original buffer solution.
October 28, 2012 by mike
0.5g of fuming h2s04 oleum is diluted with water. This solution is completely neutralized by 26.7ml of 0.4N naoh. Find the percentage of free s03 in the smaple solution. The answer 20.6% Assume that 50ml of 0.01M edta solution were added to 25ml of solution and the excess edta...
March 3, 2013 by Fai
An unknown H2So4 sample of 25.00mL vl is titrated with 0.149 M NaOH. If 45.22mL of NaOH were needed to reach the pink endpoint, what was the molarity of the unknown acid? Show work using conversion factors????? H2SO+2NaOH --> Na2SO4+2H2O Dont know where or how to start!
January 31, 2012 by April
Chemistry (College) URGENT
1.6g of an unknown monoprotic acid (HA) required 5.79 mL of a 0.35 M NaOH solution to reach the equivalence point. Determine the molar mass of the acid and given that the pH at the half way point to the equivalent point is 3.86. Calculate the Ka of the unknown acid.
October 29, 2012 by Tiffany
We add excess NaCl solution (58.44 g/mol) to 56 mL of a solution of silver nitrate (AgNO3 169.88 g/mol), to form insoluble solid AgCl. When it has been dried and weighed, the mass of AgCl (143.32 g/mol) is found to be 1.25 grams. What is the molarity of the original AgNO3 ...
September 19, 2012 by cheri
Hg2+ + 2Cl- → HgCl Mercuric nitrate was standardized by titrating a solution containing 147.6 mg of NaCl(FM 58.44), which required 28.06 ml of Hg(No3)2 solution. Part a: Find the molarity of Hg(No3)2. I already calculated the molarity to be 0.04500 M Part b: When the ...
October 16, 2011 by Asuna
I have no idea where to begin with this?? This class is moving so fast! Dr. Bob222 I made a 100 on my prelab!! and the online test was so fast I was going through my notes and I was scrambling to figure it out and look up stuff on the periodic table and all!! But I made an 80...
March 3, 2015 by Jennie
how do u set up with problem How would you prepare 165 mL of a 0.0317 m solution of benzoic acid (C7H6O2) in chloroform (CHCl3)? Just follow the definition of molarity. M = mols per L of solution I am assuming the m is molarity. But if it is molality, then molality is mols per...
June 30, 2006 by UTramos
1.Write a mathematical equation that can be used to calculate the concentration of the HCl solution after the standardization procedure (Titration #1). 2. Using LeChatelier’s principle, predict whether [OH-] in the calcium hydroxide/0.050 M NaOH solution is expected to be ...
April 16, 2012 by Cassie
Calculate (a) the moles and (b) the mass of magnesium carbonate at the start if 0.2 moles of sulfuric acid is added to the magnesium carbonate and the excess sulfuric acid made up to a 250 cm3 solution. 25 cm3 of this solution required 0.03 moles of sodium hydroxide for ...
October 9, 2014 by sabs
Question: When 1.97 grams of Pb(OH)2(s) is added to 1.00 liter of pure water at 25 C a saturated solution (some solid is present) is formed that has a pH of 8.97. Compute the Ksp value for Pb(OH)2 using the data. How do i go about getting the Molarity from the grams given and ...
May 11, 2009 by Eliz
Hey yall! i am working on a lab where we used NaOH solid (pellets) and 1.0M of NaOH solution. i was wondering is Sodium Hydroxide a substance that reacts with the enviroment? because maybe that could be like a source of error right? so basically i am wondering if both or one ...
March 19, 2007 by sandie
A 50mL solution of Histidine-HCl (Histidine: pKa1=1.8, pKa2=9.2, pKa3=6.0)is titrated with 0.500M NaOH. What is the expected pH of the histidine solution at the points in the titration when 14.0mL, 26mL, and 38mL of the NaOH titrant is added?
October 2, 2013 by Drew
A stock solution was prepared by dissolving exactly 0.4000 g of pure ASA (180.16 g/mol) in 10.00 mL of NaOH and heating the solution to a gentle boil. After cooling to room temperature, the solution was poured into a 250-mL volumetric flask and diluted to the mark with DI ...
January 28, 2010 by Tasha
a quantity of 25 ml of a solution containing both Fe2+ and Fe3+ ions is titrated with 23 ml of .02 M KMnO4 solution. as a result all the Fe2+ ions are oxidised to Fe3+ ions. Next the solution is treated with Zn metal to convert all Fe3+ ions to Fe2+ ions. Finally, the solution...
September 24, 2012 by mani
Calculate the theoretical pH after 2.50 mL and 9.50 mL of NaOH has been added in both the titration of HCl and of HC2H3O2. Indicate if the volume of NaOH is before or after the equivalence point. Compare these theoretical values with the actual values found on the titration ...
November 6, 2011 by Ashley
How do you calculate the volume of titrant needed to reach the endpoint of a reaction when you are given the mls and molarity of a strong base and only the molarity of a weak acid?
April 10, 2009 by Annie
Chemistry - repost
Why 7ml of 10M HCl? Do I add 7ml of 10M HCl 1st slowly in ice bath, then slowly adjust the pH to 7 using 10M HCl? Then to dilute to 15ml in a graduated cylinder? Thanks Posted by candy on Tuesday, September 21, 2010 at 10:03am. The following is part of a procedure for a limit ...
September 21, 2010 by candy
1. a) 50ml of water at 46.9°C were mixed with 50ml of water at 25.1°C in a calorimeter also at 25.1°C. The final temperature was 30.1°C. Assuming that neither the density of water nor its specific heat capacity change with temperature, calculate the total heat capacity of the ...
November 12, 2012 by Cicily
Titration of 25.00 mL of a monoprotic acid solution with 0.2269 M NaOH is: Initial NaOH = 3.96 mL Final NaOH = 38.84 mL (dif is 34.88mL) Based on data what is the molar concentration of acid? I did V x M = 0.03488L NaOH x 0.2269 = 0.079143 Not sure if I should have switched to...
December 7, 2012 by Terry
A solution of HCI has a density of 1.18 g/ml and is 36% (m/m). what is the molarity and molality of this solution? Assume 100g solution. Then the solute is 36 grams. Figure the moles for that. Then, you know density, so you can compute volume (100g/density) Molarity= moles ...
March 15, 2007 by nancy
We add excess NaCl solution (58.44 g/mol) to 64 mL of a solution of silver nitrate (AgNO3 169.88 g/mol), to form insoluble solid AgCl. When it has been dried and weighed, the mass of AgCl (143.32 g/mol) is found to be 1.91 grams. What is the molarity of the original AgNO3 ...
September 20, 2010 by Jake
Chemistry-Repost for DrBob222
My question was: A saturated solution of MgF2 at 23 degrees C was prepared by dissolving solid MgF2 in 1 L water. The Ksp of MgF2 is 1.5e-5. a.)Calculate the mass of MgF2 dissolved. b.) When .1 mols of solid KF was dissolved in the MgF2 solution, precipitation was observed. ...
March 21, 2014 by Anonymous
If you pass 10.0mL of a 50.0mL solution of [Co(en)2Cl2]Cl that has been reduced with Zn through a cation exchange column, you will obtain a solution that has three H+ ions for every Co3+ ion that was originally present in the sample. These H+ ions are titrated with 0.10-M ...
October 26, 2014 by xx
I have data for titration of a strong base against a strong acid when I added volumes of NaOH 1 mL at a time to 50.00 mL of HCl to see the change in pH. One of the questions says to find the molarity of the HCl solution but how do I do this with the data.
February 6, 2012 by marla
Explain how to prepare 1L of a buffer at pH 7.4 using 1M hypochlorous acid (Ka = 3.5 x 10-8) and a 1 M NaOH solution. Indicate the volume of hypochlorous acid and sodium hydroxide to use. pH = pKa + log ([A-]/[HA]) Ka= [H+][A-]/[HA] Molarity = moles/L moles = g/molecular weight
March 12, 2013 by Anonymous
An excess of zinc metal is added to 50.0 mL of a 0.100 M AgNO3 solution in a constant-pressure calorimeter. Assuming that the density of the solution is the same as for water, calculate the mass of the solution.
June 30, 2010 by Haley
I've been given the Volume of Concentrated NaOh solution (mL) and also the Concentration of Concentrated NaOh solution (M). I also have the volume of stock solution after dilution (mL). The question is asking the approximate concentration of stock solution (M) any help?
October 31, 2008 by Vanessa
calculate the mass of solid NaCl that must be added to 1.50L of a 0.100M AgNO3 solution to precipitate all the Ag+ ions in the form of AgCl. calculate the mass of AgCl formed.
December 10, 2012 by Gurjot
Concentrated hydrochloric acid is 38% HCl by weight and has a density of 1.19 g/mL. A solution is prepared by measuring 70 mL of the concentrated HCl, adding it to water, and diluting to 0.500 L. Calculate the approximate molarity of this solution from the volume, percent ...
March 15, 2015 by JUNDY
If it requires 30.0 milliliters of 1.2 molar HCl to neutralize 20.0 milliliters of NaOH, what is the concentration of the NaOH solution? Balanced equation: NaOH + HCl NaCl + H2O (3 points)
June 22, 2011 by Anonymous
I have solved the following question but i am not sure whether it is right or wrong.. Calculate the molar heat of reaction for the NaOH(aq) using the data obtained from this experiment. (this is a neutralization question) H2so4 Volume= 30ml Concentration=1.0mol/l Initial temp...
June 3, 2010 by Marium
You dissolve 1.05 grams of an unknown diprotic acid in 200.0 mL of H2O. This solution is just neutralized by 5.00 mL of a 1.00 M NaOH solution. What is the molar mass of the unknown acid?
July 19, 2013 by Tayla
CaCO3 + H2 SO4 ------> CaSO4 + CO2 + H2 O 200 g of calcium carbonate are added to 4 L of water. a. What is the molarity of the calcium carbonate solution? b. How many moles of hydrogen sulfate would be needed to react with a 25 mL sample of the calcium carbonate solution? c...
March 3, 2013 by mamta
-A sample consist 90% NaOH and 10% CaO,whats the concentration of NaOH in the solution of this 3g sample,dissolved in 250cm3. -How many cm3 of H2SO4 with concentration of 0.255M are needed for titration of 100cm3 of this solution
September 4, 2013 by plsHelp
A 1N solution of NaOH is diluted 4/20 then rediluted 1:50. What is the final normality? How many grams of NaOH are present in 100ml of the final solution? I sort of understand the basic concept, but I don't really know how to do normality problems.
May 20, 2014 by Jennie
The density of a 15.00% by mass aqueous solution of acetic acid, CH3COOH, is 1.0187g/mL. What is (a) the molarity? (b) the molality? (c) the mole fraction of each component?
February 11, 2008 by alicia
A 5.55g sample of a weak acid with Ka=1.3 x10^-4 was combined with 5.00 mL of 6.00 M NaOH and the resulting solution was diluted to 750 mL. The measured pH of the solution was 4.25. What is the molar mass of the weak acid?
April 23, 2011 by Trista Nigh
How do I do this problem Assume you dissolve 2.56 g of malic acid, C4H6O5, in half a liter of water (500.0 g). Calculate the molarity, molality, mole fraction, and weight percent of acid in the solution. (Assume the final volume of the solution is 500. mL)
July 24, 2011 by Ann