how can i determine the molarities of the acid solution?
Q. if i have the volume of the acid used= 10.35 ml the final buret reading=18.75ml initial buret reading=7.10ml volume of Na OH=11.65ml but how can i determine the moles of the solution if this is the only information givent to me (which is all in m L)
Asked by yudyzz - Fri Oct 3 13:43:32 2008 - Chemistry - 1 Answers - Comments

A. Molarity = moles of solute/ volume of solution (dm3) Molarity = number of moles of each compound / volume (dm3)
Answered by Alfie B - Fri Oct 3 13:51:40 2008

If 9.13 m L Na OH was used in the titration of a 0.471 g sample of unknown, use ratios to determine the volume o?
Q. If 9.13 m L Na OH was used in the titration of a 0.471 g sample of unknown, use ratios to determine the volume of Na OH needed in the next trial to titrate a sample mass of 0.757 g of your sample containing KHC8H4O4. What will the final buret reading be if the initial buret reading is 0.10 m L.
Asked by nacholouie - Mon Oct 26 23:44:59 2009 - Chemistry - 1 Answers - Comments

How do I go about finding the molarity?
Q. I know that M = n/v, however I am confused on how to set up this homework problem. Any help and explanation would be appreciated! Thanks in advance. A sample contains .8517 g KHP, had an initial reading; Na OH buret of .75 m L and a final reading; Na OH buret of 24.37 m L. Calculate the molarity.
Asked by dancedancedana - Wed Feb 27 14:18:02 2008 - Chemistry - 1 Answers - Comments

A. 0.8517 g of KHP / 204.22 g/mol = 0.0041705 mol m L Na OH = (24.37 m L - 0.75 m L) = 23.62 m L Na OH and KHP react in a molar ratio of 1:1 Since you started with 0.0041705 mol KHP, at equivalence point you added 0.0041705 mole Na OH. moles / liters = Molarity 0.0041705 moles / 0.02362 liters = 0.1765 M Na OH Your text may give an equation like - N x m L = mg KHP / eq. wt. or M x m L = mg KHP / molar mass Molarity x 23.62 m L = 851.7 mg / 204.22 Molarity = 0.1765
Answered by skipper - Wed Feb 27 14:29:57 2008

How do I prepare 1.0 Molar Na OH from 3.0 Molar Na OH?
Q. Basically just that, but more specifically how do I make 100 m L of said 1.0 M solution using a 50 m L Buret and a 100 m L volumetric flask?
Asked by Sam I - Sun Apr 27 21:52:12 2008 - Chemistry - 1 Answers - Comments

A. Basically, you want to dilute it by a factor of 3. Put the 3.0M Na OH into the buret. Get a clean dry 100m L volumetric flask, and dispense 33.33m L of the 3.0M Na OH. Then, add distilled water to the flask until it reaches 100m L. Put a rubber stopper on it and swirl it around a bit to mix it up properly. Easy as that :)
Answered by blauenlanze - Sun Apr 27 22:31:25 2008

A 6.00% Na OH solution by mass has a density of 1.054 g/m L. What is the minimum molarity of an HCl(aq) solution
Q. A 6.00% Na OH solution by mass has a density of 1.054 g/m L. What is the minimum molarity of an HCl(aq) solution that can be used to titrate a 2.00 m L sample of the Na OH(aq) if the titration is to be accomplished without having to refill a 50.00 m L buret used in the titration?
Asked by jap - Sun Oct 7 17:29:03 2007 - Chemistry - 1 Answers - Comments

A. Density of 1.054 g/m L 1054g/L 6.00% Na OH is 63.24g Na OH 1.581 M Na OH 2.00*1.581 = 2.00*1.581/50.00 = 0.0632 M The minimum molarity of the HCl(aq) solution required is 0.0632 M.
Answered by Hahaha - Tue Oct 9 23:32:43 2007

Help with molar volume of hydrogen lab question?
Q. Can you help me with this? I don't get how length fits into PV = n RT. How do I set this up? Your teacher wants to scale up this experiment for demonstration purposes and would like to collect the gas in an inverted 50-m L buret. use the ideal gas law to calculate the maximum length of magnesium ribbon that your teacher should use. (It was 1cm when we used a "cage".)
Asked by eraven2 - Tue Jan 18 09:16:51 2011 - Chemistry - 1 Answers - Comments

A. Sounds like you want to collect about 40-45m L of gas. Mg + 2HCl ---> H2 + Mg Cl2 At STP that would require .040L / (22.4L/mole) = 1.8E-3 moles. 1.8E3 x 24.3g/mole = 0.044g Mg. Looking at You can see that 11.5m of Mg has a mass of 12.5g. So 0.044g Mg x [11.5m / 12.5g] = 0.040m or about 4cm. You can get an actual mass/length ratio by finding the mass of a 1m strip of Mg. (You can get 3 digit precision if you use somewhat less than 1m, like 97.2cm for example.) You should also recalculate using room conditions. Have fun.
Answered by - Tue Jan 18 09:52:42 2011

How do you find the concentration of a solution?
Q. Calculate the concentration of standard sodium hydroxide solution.4 Here is one of my trials for my lab, I need to see an example so please show how you found the concentration. Mass KHC8H4O - 0.520 g Final buret reading - 20.3 m L Initial buret reading - 4.0 m L Volume Na OH used - 16.30 m L Thank you
Asked by - Tue Oct 26 22:03:23 2010 - Chemistry - 1 Answers - Comments

A. Method is :- 1) write a balanced equation for the reaction 2) calculate the number of moles of reactant - KHC8H4O (divide its weight by the molecular weight for the molecule - calculated by adding the atomic weights of all the atoms in the molecule) 3) Assuming all the KHC8H4O is reacted then the number of moles of this will give you the number of moles of Na OH (from the balance equation of the reaction) 4) divide the number of moles of Na OH by the volume (in litres) i.e. 0.01630 litres, which will give you the concentration of the Na OH solution. [This is the same method that I used for the Mg question you also asked this week.]
Answered by Julie B - Sat Oct 30 09:18:03 2010

How many militers of each solution should be mixed together to produce 19.5 ml of a solution with a ph of 4.79?
Q. given a burette filled with .11 M acetic acid and a second buret filled with .14M sodium acetate, how many militers of each soultion should be mixed together to produce 19.5 ml of a solution with a ph of 4.79
Asked by - Mon Oct 10 22:48:25 2011 - Chemistry - 1 Answers - Comments

A. The actual milliters do not matter. Its the ratio of the two liquids. Therefore mix 45%acetic and 55%sod acetate.
Answered by - Fri Oct 14 20:23:09 2011

How many m L of water has been dispensed if the initial buret reading was 0.08 m L and the final is 28.72 m L?
Q. How many milliliters of water has been dispensed if the initial buret reading was 0.08 m L and the final is 28.72 m L?
Asked by yas - Sat Oct 29 20:53:25 2011 - Chemistry - 1 Answers - Comments

A. 28.72 m L - 0.08 m L = 28.64 m L
Answered by Roger the Mole - Sat Oct 29 21:30:04 2011

what is the largest buret that will deliver 4.8 m L with an accuracy of 0.5%? site:answers.google.com?
Q. show work
Asked by Sam M - Wed Sep 3 13:07:38 2008 - Mathematics - 1 Answers - Comments

A. It is impossible to answer this question with the information provided. .5% of 4.8 m L is .024 m L. However, there are all kinds of burets, including digital burets that are extremely precise. However, let us assume that refer to a standard glass or plastic buret. For example, acrylic-burets-class- b-polymethylpentene-stopcock- nalgene/ p/0007012/ The most accurate of these is the 25 m L buret, which has an accuracy of .06m L. Not good enough. vwr-burets-automatic-self- zeroing-class-a-with-stopcock/ p/0006996/ Of this variety, the 10 m L buret has .05 m L graduations. Generally, it is assumed that a buret is accuract to half a graduation - so that will just about do it.
Answered by Answers4Everyone - Fri Sep 5 08:12:35 2008

What are sources of error in measuring the density of a solution?
Q. I recently did a lab in which I determined the density of a solution of KCl. Materials used were a funnel, 50 m L buret (to deliver the volume of KCl), and a small beaker. Now that the lab is done, I am having trouble coming up with sources of error. (NOTE: I do not mean human error, but errors that are inherent in the lab. For example, a contaminated buret would not be a source of error because we were expected to have rinsed the it before using it. An incorrectly calibrated balance would not be a source of error either.) Can anyone think of any possible sources or error? Any suggestions would be appreciated.
Asked by Shane - Wed Oct 3 17:38:43 2007 - Other - Science - 1 Answers - Comments

A. The temperature must be stated and controlled while weighing and reading volume especially. All the equipment must be kept at the stated temperature or the volume will change when it either cools or heats. Dissolved gases in the solution must be driven out before reading the volume and weight. And must be preventing from entering once the process is started. Parallax errors (really a human error) can be hard to avoid for beginners and reading the top level of the solution in the buret and not the meniscus are common mistakes (human error again).
Answered by dougger - Wed Oct 3 18:46:01 2007

Measuring with significant figures chemistry help?
Q. The beaker had 10 ml increaments Gc has 1 ml incr. The buret has I think .1 ml increaments (not sure I forgot) How many significant digits do I right down for each one. Please explain.
Asked by - Mon Sep 7 19:11:43 2009 - Chemistry - 2 Answers - Comments

A. For all of them, it's one significant figure. For the beaker (10m L)--> The zero doesn't count. If it was .100 it'd be 3 sig figs because every number after the decimal would count. If they give you 100 , it'd be one sig fig. Gc (1m L)--> Is one sig fig. Buret (1m L)--> Is one sig fig.
Answered by Raille - Mon Sep 7 19:20:13 2009

If the measured PH of the pure juice is 4.0, what is the apparent Ka of the acid?
Q. A student titrates 50 m L of apple juice and reports the following in the titration to the phenolphthalein end point with .1011 M Na OH. Final buret reading- 17.86 m L Initial buret reading- 1.01m L what is the percentage error in the result if the true volume of the juice titrated was 51 ml? If the measured PH of the pure juice is 4.0, what is the apparent Ka of the acid?
Asked by Christie - Mon Jun 11 21:03:14 2007 - Chemistry - 1 Answers - Comments

A. Try this
Answered by Greg - Mon Jun 11 21:07:42 2007

What are some sources of error in measuring the density of a solution?
Q. I recently did a lab in which I determined the density of a solution of KCl. Materials used were a funnel, 50 m L buret (to deliver the volume of KCl), and a small beaker. Now that the lab is done, I am having trouble coming up with sources of error. (NOTE: I do not mean human error, but errors that are inherent in the lab. For example, a contaminated buret would not be a source of error because we were expected to have rinsed the it before using it. An incorrectly calibrated balance would not be a source of error either.) Can anyone think of any possible sources or error? Any suggestions would be appreciated.
Asked by Shane - Wed Oct 3 17:08:54 2007 - Chemistry - 1 Answers - Comments

A. How accurately can you read the buret? The calibration marks are probably 0.10 m L or 0.05 m L and you estimate the reading to the nearest 0.01 m L. You had to make 2 readings...initial volume and final volume. The buret is probably calibrated at 20 deg C. Was the temperature of the KCl solution 20 deg C? What is the calibration accuracy of the buret? How accurately can you read the weight? (Again 2 readings...the empty beaker and the filled beaker). What is the sensitivity and accuracy of the balance?
Answered by skipper - Wed Oct 3 17:18:29 2007

What is the concentration of the total available acide in moles/L of the apple juice?
Q. A student titrates 50 m L of apple juice and reports the following in the titration to the phenolphthalein end point with .1011 M Na OH. Final buret reading- 17.86 m L Initial buret reading- 1.01m L A) What is the concentration of the total available acide in moles/L of the apple juice? B) Assuming a drop is .05 m L, what will be the percentage error introduced into the result if the final buret reading is two drops past the actual endpoint? C) What is the percentage error in the result if the true volume of the juice titrated was 51 m L? D) If the measured p H of the pure apple juice is 4.0, what is the apparent Ka of the acid?
Asked by ralph g - Mon Jun 11 19:40:26 2007 - Chemistry - 1 Answers - Comments

A. 17.86 - 1.01 = 16.85 m L Moles Na OH = 0.1011 x 16.85 /1000 = 0.00170 = moles H+ [H+]= 0.00170 / 0.050 = 0.0341 M 0.05 x 2 = 0.1 m L The volume is 16.95 m L Moles Na OH = 0.1011 x 16.95 /1000 = 0.00171 [H+] = 0.00171 / 0.050 = 0.0343 M % error = 0.0343 - 0.0341 / 0.0341 x 100 = 0.6% moles Na OH = moles H+ = 0.00170 [H+] = 0.00170 / 0.051 = 0.0333 M 0.0341 - 0.0333 / 0.0341 = 2.3%
Answered by Dr.A - Mon Jun 11 23:44:14 2007

How do you calculate the moles of Na OH dispensed from a buret?
Q. I am doing a chemistry experiment and I have run into some difficulty with one of the questions. How do you calculate the moles of Na OH dispensed from a buret? The experiment called for 4.0 grams of Na OH to be disolved in 200 m L H2O. I know the molarity of the Na OH solution together was 0.494 M. The volume of the Na OH solution dispensed was 1.85 m L. How do I convert the 1.85 m L into moles?
Asked by twin turbo - Sat Nov 7 15:46:44 2009 - Chemistry - 2 Answers - Comments

A. 0.494M is the same as 0.494 moles/liter 1.85ml(1L/1000ml)(0.494mol/L) = 9.14 x 10^-4 moles
Answered by NutrtionalAdvice - Sat Nov 7 16:13:26 2009

A 15.00 m L sample of apple jice was titrated against 0.09741 mol/L sodium hydroxide solution.?
Q. The initial buret reading was 4.86 m L and the final reading was 15.24 m L. Find the volume of sodium hydroxide used to neutralize the apple juice.
Asked by cutiepieee - Thu Nov 29 11:02:58 2007 - Chemistry - 2 Answers - Comments

A. V of Na OH = 15.24 - 4.86 = 10.38 m L=> 0.01038 L Moles Na OH = Molarity x Volume = 0.09741 x 0.01038 = 0.001011
Answered by Dr.A - Thu Nov 29 11:11:18 2007

Calculate how many milliliters of titrant would be required to reach the endpoint if a sample contained?
Q. Calculate how many milliliters of titrant would be required to reach the endpoint if a sample contained 10.0 mg of vitamin C? Keep in mind that a standard buret holds 50.00 m L of titrant.
Asked by sarah o - Mon Nov 5 23:31:35 2007 - Chemistry - 1 Answers - Comments

A. We need to know the identity of the titrant.
Answered by eggyu74 - Mon Nov 5 23:34:56 2007

what is the molarity of acetic acid in the following vinegar sample?
Q. You titrated 22.32 ml vinegar with 0.5172 M Na OH . The initial Na OH buret reading is 1.18 ml and the final Na OH buret reading is 21.35ml.
Asked by - Wed Mar 3 00:16:59 2010 - Chemistry - 2 Answers - Comments

A. V_Na OH = 21.35 m L - 1.18 m L = 20.17 m L C_Na OH = 0.5172 mol/L V_Acetic Acid = 22.32 C_Acetic Acid = x The Equation is Na OH + HC2H302 ==> Na C2H302 + H20 It is a 1 to 1 ratio. C_Na OH*V_Na OH = C_Acetic Acid * V_Acetic Acid 0.5172*20.17 = C_Acetic Acid * 22.32 C_Acetic Acid = 0.5172*20.17/22.32 = 0.4674 mol/L
Answered by jcherry_99 - Wed Mar 3 00:31:29 2010

A volume of 13.69 m L of 0.1050 M Na OH solution was used to titrate a 0.587 g sample of unknown containing KHSO?
Q. A volume of 13.69 m L of 0.1050 M Na OH solution was used to titrate a 0.587 g sample of unknown containing KHSO4. What is the percent by mass of KHSO4 in the unknown? Tries 0/99 In this problem what mass of sample in grams would be needed to deliver about 22.50 m L in the next trial? Tries 0/99 In the second trial above, exactly 0.955 g was transferred into a flask to be titrated. If the initial buret reading is 0.10 m L, predict what the final buret reading be. Tries 0/99
Asked by - Sun Nov 20 17:33:01 2011 - Chemistry - 1 Answers - Comments

A. Hello 13.69 m L of 0.1050 M Na OH = 0.00143745 moles Na OH 1 mol Na OH titrates 1 mol KHSO4 --> moles KHSO4 = 0.00143745. Molec. mass KHSO4 = 136.17 g/mol 0.00143745 moles = 0.00143745*136.17 g = 0.19574 g = 0.19574*100/0.587 % = 33.345 % <--- ans --- 0.587 * 22.5/13.69 = 0.9647 g --- 13.69*0.955/0.587 = 22.272 m L + 0.1 m L = 22.372 m L Regards
Answered by Ossi G - Sun Nov 20 18:33:40 2011