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This page lists questions and answers that were posted by visitors named smiley.

Questions

The following questions were asked by visitors named smiley.

Where can I find the answers to these questions in my text, "fundamentals of analytical chemistry" by skoog, west, holler and crouch. 1. Why is acetylsalicylic acid analyzed using back titration? 2. Discuss the importance of simmering the tablet in the Na...

18 years ago

What is an aliquot factor? It is a whole divisor. For instance 5 is an aliquot factor of 15, and 15 is an aliquot factor of 150. I'm sorry, but I don't seem to understand it. For example, how do you get the aliquot factor of 50? 2, 5, 10, 25 would be aliq...

18 years ago

Topic: Iodometry 1. The importance of precipitating the Cu2+ ions using NH3 and redissolving it with acetic acid 2. What are other means of detecting endpoint in iodometry aside from adding starch indicator 1. A pH that is too low leads to excessive oxida...

18 years ago

Topic: Iodometry 1. the reason why the Cu2+ solution has to be titrated immediately after addition of KI Answered above.

18 years ago

Topic: Iodometry 1. the reason why the Cu2+ solution has to be titrated immediately after addition of KI - I thought, because if allowed to stand for a long time, iodine will volatilize and a change in concentration of iodine will occur...is this right? P...

18 years ago

1. What are other methods of moisture determination besides oven drying? 2. During the drying of samples, the weight is considered constant when the last two weights are within ± 0.0003 grams. What is the reason for this? For #1, here is a site for you to...

18 years ago

experiment: Gravimetric determination of moisture in fertilizer samples 1. What are the advantages of weighing by difference to direct weighing when using an analytical balance? 2. Why are the samples grinded before drying in the oven? Weighing by differe...

18 years ago

Please help me through this problem... A 0.5117 gram fertilizer containing phsphorus was oven dried. The weight of the dried sample is 0.4998 grams. However, 10% moisture is still retained in the sample. Calculate the moisture content in the sample in as...

18 years ago

The phosphorus in a completely dried fertilizer sample weighing 0.4498 grams was precipitated as MgNH4PO4*6H2O. The precipitate weight was determined to be 236.8 mg and ignited to Mg2P2O7. The weight of the ignited precipitate was 268.9 mg. Calculate the...

18 years ago

what does it mean if I got a % relative error that is higher than 100%? - would it mean that I did the experiment erroneously?

18 years ago

Based on the experimental data, I was able to calculate the experimental pKa value which is 5.04 and the literature value of the pKa for KHP is 5.51. If I would be computing for the relative error between the two pKa's it would be 8.52994555%. But then, w...

18 years ago

In experiment concerning potentiometric determination of puriy and Ka of KHP, we obtained an experimental pKa of 5.04 and when compared with the theoretical pKa of 5.51, we obtained a % relative error of 192%. Could this error mean that a cerain impurity...

18 years ago

1. Why Beer's law is expressed in terms of absorbance instead of transmittance? 2. What is the significance of spectral scanning? 3. What is the importance of the baseline?

18 years ago

Why should an Fe3+ solution be used in calibrating the spectrophotometer for the spectrophotometric determination of iron in Fe2+ complexes?

18 years ago

Why is an Fe3+ solution instead of an Fe2+ solution used in calibrating the spectrophotometer? Note: hydroxylamine hydroxide is added to the Fe3+ solution then 1,10 phenanthroline is added to the solution after the addition of hydroxylamine hydroxide. Aft...

18 years ago

I'm sorry but I still don't understand the concept of spectral analysis and the baseline. What does these words mean and what are they for? I'm confused... Note: the experiment determines the concentration of iron in iron(II) phenanthroline by spectrophot...

18 years ago

Why is it important that the sequence of addition of reagents be followed? What could possibly go wrong when this is not followed? Reagents added: 1st: Fe3+ solution 2nd: 2.00 mL 10% NH2OH-HCl (hydroxylamine hydrochloride) 3rd: excess 0.20% 1,10-phenanthr...

18 years ago

"experiment: spectrophotometric determination of the acid dissociation constant of methyl red" 1. Why are matched cells used in the experiment? 2. Why is pH plotted against log([MR-]/[HMR])? 3. Why is it right that HMR has a pH equal to 2 and MR- to have...

18 years ago

"experiment: spectrophotometric determination of the acid dissociation constant of methyl red" 1. Why is pH plotted against log([MR-]/[HMR]) to get the pKa of methyl red? 2. Why is it right that HMR has a pH equal to 2 and MR- to have a pH equal to 8?

18 years ago

Why can't we add charcoal to benzoic acid in purification by sublimation

17 years ago

What is the effect of using cyclohexane as the solvent in the bromination of acetanilide?

17 years ago

What is the effect of cyclohexane as the solvent in the electrophilic aromatic substitution of acetanilide by bromine?

17 years ago

I am doing a Frayer model and my spelling word is region. That is a non-characteristic for region? Thank you for your help.

16 years ago

Which sentence is better? 1. On May 15, 1941-July 17, 1941, DiMaggio held the longest consecutive game hitting streak (56 games). 2. On May 15-July 17, 1941, DiMaggio held the longest consecutive game hitting streak (56 games). Please Help!! Thanks!!

16 years ago

what comes next? O,T,T,F,F,S,S,E,......

16 years ago

what is the material between 2900 kilometers and 5200 kilometers below earths surface inferred to be

15 years ago

y'=xy/2ln y how do you solve the differential equation by seperation of variables

14 years ago

what are the characteristics of plants and animals

13 years ago

can anyone plz tell me a gud story if u were evr a shape for example this wut my friend her shape was a rectangle she wrote that the rectangle is going to apply for a job and the job is of an ice cream cart meaning like the ice cream cart and at the end t...

13 years ago

what is an irregular polygon. what is congruent. what are corresponding angles. what are corresponding sides. FULL SENTENCES PLZZZ!!!!

13 years ago

does anyone know a poem about seashores and it has to be aroung grade 6 level thank u?

13 years ago

The current-density magnitude in a certain circular wire is J = (2.75 × 10 10 ⁄ )r 2 , where r is the radial distance out to the wire’s radius of 3.00 mm. The potential applied to the wire (end to end) is 60.0 V. How much energy is converted to thermal en...

12 years ago

what contributions has the arab society made to the canadian society?!? ANSWER IN COMPLETE SENTENCES PLEASE AND EXPLAIN!!!!

11 years ago

what are some ideas for science fair projects gr.8?!?! and please give an experiment with it thank u!!

11 years ago

A kicker strikes a ball with a strong force. a) Explain the evidence that shows the ball is not filled with liquid? b) Describe what is happening to the particles inside the ball? * chapter is about forces and pressure*

11 years ago

A. The amount of an employee's income that an employer sends directly to the federal, state, or local tax authority B. Taxes, insurance, and saving plans deducted from a paycheck C. Provides a summary of the payroll information for each pay period D. Comm...

6 years ago

Answers

The following answers were posted by visitors named smiley.

So, the moisture content (as received) is ((0.5117-0.4998)/0.5117)* 100 = 2.326% and the the moisture content (dry basis) is ((0.1*0.4998)/0.5117)*100 = 9.767% and when the sample is completely dried, it would weigh 0.4998-(0.1*0.4998) = 0.4498 Am I right...

18 years ago

what is apectral scanning? I really don't have an idea on this. As for the baseline, we indicated a range of 350 nm to 600 nm in the spectrophotometer and found that lambda max is at 510.4 nm. What then is the significance of the baseline?

18 years ago

I'm sorry yes. could you tell me what is a non characteristic of region? Please help, thank you.

16 years ago

How did you get that answer then?

16 years ago

which sentence is correct, #2 or #3? SraJMcGin chose #2 & Ms. Sue chose #3. I do not know which one to choose..... HELP!!

16 years ago

Actually, I wanted to use the sentence below: During May 15-July 17, 1941, DiMaggio held the longest consecutive game hitting streak (56 games). Does that make sense? **It makes more sense because it was during that year, not between it. Thanks!!

16 years ago

Power & greed are sometimes the main cause of war because: Power: You are strong & want to gain more land, food, things, etc... Definition: The possession of control or command over others; authority. Ability to do or act; capability of doing or accomplis...

16 years ago

I think he did set more than 1 0r 2 records, right?

16 years ago

Hint: The answer is not "E".

16 years ago

Here is another one: J,F,M,A,M,J,J,A,.....

16 years ago

you have 157.5 mmol of AgNO3 and 243 mmol of MgCl2. From the balanced chemical equation, 1 mol of MgCl2 would consume 2 moles of AgNO3. It would then require 315 mmol of AgNO3 to completely consume the MgCl2. Therefore, AgNO3 is the limiting reactant and...

16 years ago

ln(K1/K2)=(∆Horxn/R)((1/T2)-(1/T1)) ln((6.5x10^-2)/K2)=((-49.5 kJmol^-1)/R)((1/(250+273.15))-(1/(100+273.15))) That's it! Just solve for K2. Don't forget that your R must have the units of kJ/molK. Hope this helps. Cheers!

16 years ago

Its name is methyl ethanoate. First, you must find the carboxylate part. In your case, this is ethanoate. Next, determine what is attached to the O (not the one double bonded to C) of the carboxylate. In your case, this is CH3 and you would call this meth...

16 years ago

Well - Two fractions equivalent to 2/5: 4/10 an d6/15. - Two fractions equivalent to 7/11: 14/22 and 21/33. - Two fractions equivalent to 150/325: 300/650 and 450/975. To solve this you should of multiplied each fraction by a number (E.G. 2/2) For 2/5, I...

13 years ago

do u mean sling?

13 years ago

pollution, landfills, animals homes destroyed, less space on earth,

well not really because graphs are used to display your data, and just the date would be considered as ur info not the display.

11 years ago

D0 Light box

11 years ago

1. B Correct 2. A Correct 3. B C STUDY GUID 88-93 4. B Correct 5. A Correct 6. B Correct 7. D A STUDY GUIDE 95 8. B Correct 9. C Correct 10. D B STUDY GUIDE 86-87 11. A Correct 12. B Correct 13. D Correct 14. A Correct 15. A D STUDY GUID 86-88 16. C B STU...

10 years ago