Documents about Methyl Orange

  • 8 Pages

    Chemical_equilibrium

    UC Davis, CHE 2b

    Excerpt: ... I. You considered the equilibrium: Fe 3+(aq) + SCN-(aq) Fe(SCN)2+(aq), and compared the color of the solutions in four test tubes. In the third test tube, you added 6 M NaOH dropwise. How do you explain the formation of a precipitate and the shift in equilibrium in terms of LeChatelier's Principle? You Scored 2 points out of 3 Possible Your Answer: a. The addition of NaOH produced the precipitate, Fe(OH)3, which removed Fe3+ from the system. To reduce the stress of the removal of Fe3+ and to re-establish equilibrium, the system shifted to the left increasing [Fe3+] and decreasing the [Fe(SCN)2+]. Increasing the [Fe3+] produced a yellow colored solution. 11) Scoring Scheme: 3-3-2-1 Part II. You considered the properties of two acid-base indicators, phenolphthalein and methyl orange . Many indicators are weak acids in water and establish the equilibrium: HIn(aq)(Color 1) + H2O(l) H3O+(aq) + In-(aq)(Color 2). Indicators change color depending on whether they are in a protonated (HIn) or unportonated (In -) form. ...

  • 8 Pages

    lab 3

    UC Davis, CHE 2b

    Excerpt: ... librium: Fe 3+(aq) + SCN-(aq) Fe(SCN)2+(aq), and compared the color of the solutions in four test tubes. In the third test tube, you added 6 M NaOH dropwise. How do you explain the formation of a precipitate and the shift in equilibrium in terms of LeChatelier's Principle? You Scored 1 point out of 3 Possible Your Answer: a. The addition of NaOH produced the 3+ precipitate, Fe(OH)3, which removed Fe from the system. To reduce the stress of the removal of Fe3+ and to re-establish equilibrium, the system shifted to the left increasing [Fe3+] and decreasing the [Fe(SCN)2+]. Increasing the [Fe3+] produced a yellow colored solution. 11) Scoring Scheme: 3-3-2-1 Part II. You considered the properties of two acid-base indicators, phenolphthalein and methyl orange . Many indicators are weak acids in water and establish the equilibrium: HIn(aq)(Color 1) + H2O(l) H3O+(aq) + In-(aq)(Color 2). Indicators change color depending on whether they are in a protonated (HIn) or unportonated (In-) form. What is the equilibrium exp ...

  • 6 Pages

    benzoic acid extraction lab

    Pittsburgh, CHEM 330

    Excerpt: ... an organized manner. Such a tool also proves helpful in visualizing each reaction that takes place with each molecule in the mixture during an extraction. And last but not least, a final point must be made about the extraction process: multiple extractions produce a better result than only one extraction. By conducting more than one extraction, more product will be collected Scheme 1 Methyl Orange : CH2OH CH3 N N N CH3 ; ( COOH Benzoic Acid: Cellulose: O OH OH O O H OH 3 CH2OH O ; OH ) n; -O S in ether , filter insoluble soluble COOH cellulose + methyl orange Scheme 2 COOH + methyl orange NaOH (1M) aqueous COO- organic Na+ methyl orange HCL (6 M) COOH Reagent Table: Name Formula MW Mass Density g/mol or g/cm3 Volume 122.1 4.17 g 1.316 m.p., C b.p., C Benzoic acid C7H6O2 121.4-123.0 248.9-250.4 Diethyl ether C4H10O 74.1 50 mL 0.79 -119.1-115.9 200-300; decomposes 260-270 34.1-35 Methyl orange Cellulose C14H ...

  • 3 Pages

    Dye lab

    Arizona, CHEM 243A

    Excerpt: ... Introduction In this lab we will be synthesizing the azo dye, methyl orange , to test its dyeing properties on different kinds of fabrics. Since dyes are used for many things in the world such as food and fabric dyes, it is important to see the effect they have when put on various fabrics and why they are different. It will also be used to test it as a pH indicator and to demonstrate the color bleaching process. Substance sodium carbonate sulfanilic acid sodium nitrite hydrogen chloride N,Ndimethylaniline acetic acid NaOH NaCl MW 105.9 9 173.1 9 69 36.46 121.1 8 66.05 39.99 58.44 2 MP BP 851 288 270 114 2.4 5 16. 5 318 801 NA NA 320 -85 194 118 139 0 146 5 d 2.5 1.49 2.2 1.47 7 4.17 1.04 9 2.1 2.16 Safety Considerations irritation to skin, eyes and respiratory system very hazardous corrosive, flammable cause chemical burns, blindness, scarring Procedure See lab notebook Calculations Percent Yield: .456/ .86 x 100= 53% Results Fabric spun diacetate bleached cotton spun polyamid ...

  • 5 Pages

    Midterm #2.2 Ans

    UCLA, CHEM 20L

    Excerpt: ... hat result. The precision refers to the deviation or variation of a set of results from the mean. 4. Acid base indicators are usually weak acids, which can exist in solution as either the undissociated acid or the conjugate base. The two species have different colors. As the pH of the titration changes, the predominant form of the indicator changes from one form to the other. (Chemistry Experiments for Physical Science and Engineering Majors, pp58) (a) In Assignment 4 you recorded the pH ranges for the color changes for four indicators. Based on that data, complete the following table. SA = strong acid, SB = strong base; WA = weak acid, WB= weak base color of Appropriate indicator for titration color of pH Indicator range of undissociated conjugate of 0.1000 M reagents of acid and base (Explain below) base indicator color change SA-SB WA-SB WB-SA Bromocresol 3.8 5.4 yellow blue X green Phenol8.2 colorless pinkX X phthalein 10.0 magenta Methyl red 4.8 6.0 red yellow X Methyl orange 3.2 4. ...

  • 3 Pages

    Indicators_expt

    UCLA, CHEM 20L

    Excerpt: ... Chemistry 20L Revised Procedures for Assignment #4 - Titrations & Indicators (i) (ii) Read pages 56-58 in the lab manual for the introduction and background of the experiment Pre-lab study questions for this experiment may be found on pages 58-59 in the lab manual. Use the following revised procedures when writing your reports. At the beginning of the lab period, your TA will divide the class into pairs. If the class has an odd number of students, one person will be assigned to work alone. In this assignment, your group will determine and compare the calculated concentration of a sulfuric acid solution based on the results obtained from experimental end points using three different indicators and a pH meter. The titrations will be performed using a standard base and a sulfuric acid solution with an unknown concentration. The three different acid/base indicators that your group will use in this assignment are: Bromocresol Green, Methyl Orange , and Phenolphthalein The standard base used in this assignmen ...

  • 3 Pages

    SamplePages

    Mt. Holyoke, CHEM 201

    Excerpt: ... hloride NaCl BaCl2 58.44 208.23 (saturated) 0.1 M Toxic Sample laboratory notebook pages Table of Reagents, continued Calcium chloride Oxalic acid Potassium oxalate Methyl orange (indicator) Phenolphthalein (indicator) -0.1 % -0.1 % K2C2O4 166.22 0.5 M CaCl2 H2C2O4 110.98 90.038 0.1 M 0.5 M Experimental Plan 1. Chromate Dichromate Equilibrium Obtain 3 mL of 1 M K2CrO4 in a test tube Add several drops 3 M H2SO4; mix Observations Add several drops 6 M NaOH; mix Observations (Note: Its a good idea to leave open space in a prepared table for corrections and additions.) Add several drops H2SO4; mix Observations Indicator Equilibria Obtain 3 mL water in a clean test tube Add one drop methyl orange Observations Add 2 drops 6 M HCl Observations Sample laboratory notebook pages (Note: The blank left-hand pages can be used for the recording of raw data: masses weighed at the balance, volumes measured at the bench, and other information or observations that you didnt anticipate in preparing th ...

  • 4 Pages

    Midterm #2.2

    UCLA, CHEM 20L

    Excerpt: ... nge of undissociated conjugate of 0.1000 M reagents of acid and base (Explain below) base indicator color change SA-SB WA-SB WB-SA Bromocresol green Phenolphthalein Methyl red Methyl orange Give your reasoning for choice of titration. (b) Calculate the pH of a 1.85 x 10-2 M solution of Ba(OH)2. 2 5. A 10.00-mL sample of an unknown acid was titrated with 0.1015 M NaOH. The titration data is shown below along with the Excel plot of the first derivative ($pH/$V vs volume base) graph in the vicinity of the equivalence point. Vol NaOH 0.07 3.02 5.98 9.13 12.22 12.49 13.00 13.90 13.98 14.10 14.14 14.22 14.25 14.31 pH 2.59 4.03 4.46 4.82 5.29 5.39 5.53 5.92 5.99 6.09 6.14 6.21 6.28 6.37 Vol NaOH 14.36 14.40 14.45 14.49 14.55 14.60 14.64 14.69 14.74 14.81 14.92 15.00 15.49 pH 6.47 6.59 6.78 7.24 8.55 9.71 10.40 11.07 11.32 11.44 11.53 11.66 11.97 40.00 35.00 30.00 25.00 20.00 15.00 10.00 5.00 0.00 14.20 14.40 14.60 Volume of NaOH 14.80 15.00 (a) What is the equivalence point volume? (b) What is the concentrati ...

  • 3 Pages

    Midterm #2.1 Ans.

    UCLA, CHEM 20L

    Excerpt: ... e performed two experiments with titrations. Selecting an indicator for a titration is a very important step in designing a titration. Given the following indicator data, choose the best indicator for the following titration situations. Justify your choice. Limit your answers to 2-3 sentences Indicator Methyl Orange Bromothymol Blue Phenolphthalien (A) (5 points) Weak Acid/Strong Base Best indicator - Phenolphthalien A weak acid/strong base titrations have an equivalence point that is slightly basic, therefore an indicator with a basic color transition would be best. pH range of color change 3.3 4.1 6.0 7.6 8.3 10.0 (B) (5 points) Strong Acid/Weak Base Best indicator Methyl Orange or Bromothymol Blue A strong acid/weak base titration has an equivalence point that is slightly acid, therefore an indicator with an acidic color transition would be best. Either Methyl Orange or Bromothymol Blue would be good choices. (C) (5 points) Strong Acid/Strong Base Best Indicator - Bromothymol Blue A stro ...

  • 5 Pages

    methylorange

    Minnesota, CHEM 4643

    Excerpt: ... Material Safety Data Sheet Methyl Orange Solutions ACC# 40120 Section 1 - Chemical Product and Company Identification MSDS Name: Methyl Orange Solutions Catalog Numbers: SLN6126, SM54-500 Synonyms: None. Company Identification: Fisher Scientific 1 Reagent Lane Fair Lawn, NJ 07410 For information, call: 201-796-7100 Emergency Number: 201-796-7100 For CHEMTREC assistance, call: 800-424-9300 For International CHEMTREC assistance, call: 703-527-3887 Section 2 - Composition, Information on Ingredients CAS# Chemical Name Percent EINECS/ELINCS 547-58-0 Methyl orange 0.05-.15208-925-3 6381-92-6Disodium ethylenediaminetetraacetate dihydrate 0.008 unlisted 7732-18-5Water Balance 231-791-2 Hazard Symbols: None listed. Risk Phrases: None listed. Section 3 - Hazards Identification EMERGENCY OVERVIEW Appearance: yellow orange liquid. Caution! The toxicological properties of this material have not been fully investigated. May cause eye and skin irritation. May cau ...

  • 14 Pages

    L4_115b08

    USC, CHEM 115b

    Excerpt: ... ll need to get k from kobs. First lab: Measuring kinetics of Methyl Orange /Sn(II) reaction Sn2+ + 4H+ + MeO - > Sn4+ + other products orange colorless R=- d [ MeO] = k[ MeO]m [ H + ]n [ Sn 2+ ]l dt Trick: reduce the rxn order by using large excess of H+ and Sn2+ -> determine m: R=- d [ MeO] = keff [ MeO]m dt keff = k[ Sn 2+ ]l [ H + ]n Ch. 18. Chemical Kinetics Next Concepts Rxn mechanism: elementary steps that lead to a final result; molecularity - Rate limiting step and fast equilibrium - Steady state approximation - Rate of enzyme reactions and atmospheric reactions Factors that affect rate: - concentration - temperature - catalyst Special topics - femtochemistry - atmospheric chemistry Reaction mechanisms: How does the reaction happen? Why rate laws are what they are? Mechanism: a series of elementary rxns Elementary rxn: a reaction that occurs in one step Example: hydrogen combustion 2H2 + O2 2H2O H= -242 kJ/mol Exothermic rxn, releases a lot of energy. Is i ...

  • 18 Pages

    Lab 2 Ch. 3

    USC, BISC 220LG

    Excerpt: ... ic environment, where the uptake of water is eventually balanced by the elastic wall pushing back on the cell. H2O isotonic H2O H2O hypertonic H2O Turgid (normal) Flaccid Plasmolyzed Figure 7.13 Procedure Part A. Diffusion in a solid Agar plates: KMnO4( potassium permanganate) and methyl orange Part B. Diffusion in a model cell Dialysis Part C. Movement of molecules across cell membranes RBC and plant cells Part A. Diffusion in a Solid Prepare 3 plates For each plate Draw two spots on dish 5 cm apart Label the spots A and B Place a few crystals of KMnO4 on spot A Place a few crystals of methyl orange on spot B Incubate one plate each @ 4C, 22C, 37C Do it first & move on to Part B & C Measure diameter of diffused species Calculate diffusion rate Part B. Diffusion in a Model Cell Two solutions will be separated by an artificial membrane Membrane is selectively permeable Based on pore size & composition of membrane ...

  • 2 Pages

    Lab9LD

    Georgia Tech, CHEM 1310

    Excerpt: ... Conclusion/Discussion The purpose of this lab was to study the properties of Bronsted-Lowry acids and bases, pH scale and equilibria associated with common household acids and bases. Acids and bases are often described as being "weak" or "strong". While this classification seems somewhat arbitrary, other more quantitative descriptors exist. For acids, Ka values are commonly used. The Ka value is an indication of acid strength. The larger the value of the Ka, the stronger the acid. This value is characteristic of the acid and can be used to help identify an unknown acid. The Ka values we determined for phenolphthalein, methyl orange , bromethymol blue, and the universal indicator were for the most part close to the literature values of Ka. Reasons for our numbers being slightly larger could simply be human error, mixing wrong etc. For example, our determined Ka value for phenolphthalein was 1.5*10-8 while the literature value was 1*10-10 . Our pH could be slightly off because we added one drop too many or one ...

  • 2 Pages

    ENDLAB9

    Georgia Tech, CHEM 1310

    Excerpt: ... Conclusion/Discussion The purpose of this lab was to study the properties of Bronsted-Lowry acids and bases, pH scale and equilibria associated with common household acids and bases. Acids and bases are often described as being "weak" or "strong". While this classification seems somewhat arbitrary, other more quantitative descriptors exist. For acids, Ka values are commonly used. The Ka value is an indication of acid strength. The larger the value of the Ka, the stronger the acid. This value is characteristic of the acid and can be used to help identify an unknown acid. The Ka values we determined for phenolphthalein, methyl orange , bromethymol blue, and the universal indicator were for the most part close to the literature values of Ka. Reasons for our numbers being slightly larger could simply be human error, mixing wrong etc. For example, our determined Ka value for phenolphthalein was 1.5*10-8 while the literature value was 1*10-10 . Our pH could be slightly off because we added one drop too many or one ...

  • 4 Pages

    Chemistry 208 Lab Report 5

    Cornell, CHEM 2080

    Excerpt: ... aOH, and a strong acid, 0.0984 M HCl. First, the pKa was estimated through eye vision and a pH meter. To perform this procedure, a certain amount of HCl was poured into a beaker, and some of the unknown acid-base indicator was added. Next, some of the NaOH was titrated into the HCl solution. When the color of the solution changed, the pH was measured with the pH meter. It registered that the pH was relatively about 10.05; therefore we concluded that the pKa of the indicator was about the same as the registered pH. Next, we accurately tried to calculate the pKa by measuring the wavelength of the maximum absorbance of the unknown indicator. Before testing the unknown, a trial test was performed using methyl orange instead of the unknown indicator. A drop of the methyl orange was placed in a cuvet in a solution of HCl and then its wavelengths were found using the visible spectrophotometer. This was repeated using a solution of the NaOH. The wavelengths of the maximum absorbance were found to be concurrent with t ...

  • 4 Pages

    07F CHEM 14CL Acid-BaseReviewKey

    UCLA, CHEM 14CL

    Excerpt: ... Chemistry14ClAcidBaseChemistryReviewKey Fall2007 1. Bariumhydroxidefurnishestwomolesofhydroxideinsolutionforeachmoleofbarium hydroxidethatyoustartwith,andHCldonatesonemoleofprotons/moleofacid.Thusthe concentrationof[OH]=0.0800M.Since equivalentsofaci ...

  • 4 Pages

    Acid-BaseReviewKey

    UCLA, CHE 104

    Excerpt: ... d pH = 10.39 Halfway through the titration, after 2.5 mL of acid has been added, the pOH = pKb = 5.92 and pH = 8.08 At the equivalence point the conjugate acid hydrolyzes to give a pH below 7. Calculation gives [H+] = 1.67 x 10-5, pH = 4.78 14. Acid base indicators are usually weak acids, which can exist in solution as either the undissociated acid or the conjugate base. The two species have different colors. As the pH of the titration changes, the predominant form of the indicator changes from one form to the other. Complete the following table. SA = strong acid, SB = strong base; WA = weak acid, WB= weak base pH color of color of Appropriate indicator for titration Indicator range of undissociated conjugate of 0.1000 M reagents of acid and color indicator base base (Explain below) change SA-SB WA-SB WB-SA Bromocresol 3.8 5.4 yellow blue X green Phenol8.2 colorless pinkX X phthalein 10.0 magenta Methyl red 4.8 6.0 red yellow X Methyl orange 3.2 4.2 red yellow X Chemistry 14CL 3 Acid-Base Rev ...