Gravimetric Determination Of Nickel Dmg

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Table of Content

Page
1.Title of experiment
2.Table of contents
3Abstract 2
4.Introduction 3
5.Materials and methods 4
6Results 6
7Discussion 8
8.Conclusion 10
9.Reference 11

Gravimetric Determination of Nickle in Steel Introduction The nickel in a steel sample can be precipitated from a slightly alkaline medium with an alcoholic solution of dimethylglyoxime (DMG). Tartaric acid is introduced to complex iron(III) and prevent its interference. After drying at 110 oC, the organic nickel compound, Ni(C 4 H 7 O 2 N 2) 2. The gravimetric analysis involves the quantitative determination of ions or species present in the sample by measuring the mass. The gravimetric analysis of nickel is an analytical technique used to determine the mass of any nickel sample by relative assessment of the compound containing similar elements.

Abstract

Using DMG and borax buffer, 500 ng of nickel(II) was precipitated and detected in 40 s while employing only a 1.0 ml sample. In addition to meeting new NASA short term exposure concentration requirements, the minimal volume and fast analysis time are dramatic improvements over similar sorption-spectroscopic methods 24, 25, 37, 38. Experiment 7-023: Gravimetric determination of Nickel in a Five-cent Coin A gravimetric determination of a substance involves the separation of that substance in a form which may be weighed accurately and is of known composition. The main objective of this experiment is to determine the concentration of nickel (II) ion in a nickel sample solution of unknown concentration. Gta 5 download for android apk obb low mb. Gravimetric method is used whereby dimethylglyoxime (1% in alcohol) is added to precipitate the analyte which is later separated from the solution and dried. Practical 4 Gravimetric Determination of Nickel Goce Pacarski Mass of Nickel in Precipitate = Mass of Precipitate x Molar Mass of Nickel Molar Mass of NiDMG = 0.2345 x 58.71 288.9356 = 0.047649g% Nickel in Sample = Mass of Nickel x 100% Mass of Sample = 0.047649 x 100% 0.2184 = 21.82g/100g (w/w).

The main objective of this experiment is to determine the concentration of nickel (II) ion in a nickel sample solution of unknown concentration. Gravimetric method is used whereby dimethylglyoxime (1% in alcohol) is added to precipitate the analyte which is later separated from the solution and dried. The concentration of the sample solution has been calculated as 0.109 mg/mL.

  • Introduction

In this lab, you will be precipitating nickel (Ni2+) from an unknown Nickel ore. You will need to determine the % of nickel in the unknown which you will report on your unknown card and your lab report. Accuracy will play a large part of your grade so do every step CAREFULLY!

Nickel is precipitated with an organic precipitating agent termed dimethylglyoxime (DMG) as shown below. Organic reagents often react with more than one metal ion, therefore, adequate specification can be achieved with concentration and pH. DMG forms a chelating complex with the metal ion and forms a bright red precipitate Ni(C4H7N2O2)2 in a slightly basic solution of 1:1 aqueous ammonia. The precipitate is washed with a 30% ethanol solution and weighed (constant weight) after drying the frits in the oven at 110EC for 2 hours.

  • Background Information of Method

The gravimetric method used in this experiment is among the most accurate methods but time-consuming. Overall, this method includes precipitation of the analyte in aqueous solution which is then separated from the mother liquor, washed, heated to constant weight and weighed as compound of definite composition.

Technique used

Gravimetric Determination Of Nickel Dmg Download

Gravimetric analysis is one of the most accurate analytical methods available. It is concerned with the determination of a substance by the process of weighing. The element or radical to be determined is converted into a stable compound of definite composition and the mass of the compound is determined accurately. From this, the mass of element or radical is calculated.

The gravimetric analysis involves

a) precipitation

b) filtration

c) washing of the precipitate and

d) drying, ignition and weighing of the precipitate.

  • Rationale / Purpose of Experiment

This experiment aims to determine the concentration of the nickel (II) ion (Ni2+) in a sample solution that contains it.

  • Background Information of Analyte

The analyte in this experiment is Ni2+. As an element, it is one of the transition metals alongside copper, zinc, iron, manganese, etc. In ionic form, it usually possesses a charge of +2 and gives the solution containing it a green colour. When in contact with basic chemicals, such as aqueous sodium hydroxide (NaOH) and ammonia, it precipitates into a green nickel salt compound; this means nickel (II) solution is acidic. In this experiment, it comes in contact with dimethylglyoxime (DMG, C4H6(NOH)2) and precipitated as nickel dimethylglyoximate (Ni(DMG)2) in red. Best of mohammad rafi mp3 songs download.

Gravimetric determination of nickel dmg download
  • Materials and Methods
    • Apparatus
Nickel

Volumetric flask (100 mL), beaker (400 mL), labelling tape, pipette (20 mL), measuring cylinder, microwave oven, thermometer, dropper, electronic weigh, glass rod, basin, sintered glass crucibles, desiccator, tongs, blue litmus paper, aspirator, side-arm filtering flask, retort stand, retort clamps.

  • Chemicals and Reagents

Nickel (Ni2+) sample solution, distilled water, dimethylglyoxime (DMG, 1% in alcohol), nitric acid (HNO3, 6 M), urea, oxalic acid, dilute ammonium hydroxide (NH4OH).

Gravimetric Analysis Of Nickel Using Dimethylglyoxime Lab Report

  • Experimental Procedures

A sample of nickel solution in a 100 mL volumetric flask is obtained and diluted to the mark with distilled water. The flask is shaken to mix the solution thoroughly and three aliquot samples (20 mL) are transferred into separate 400 mL beakers using a pipette. Each replicate is labelled as 1, 2 and 3 respectively and added distilled water (approximately 150 mL) before being heated to around 80°C in a microwave oven. DMG (10 mL) is added slowly to each replicate which their acidity are later checked with blue litmus paper. HNO3 (6 M) is added dropwise if any of the replicates is not acidic. Urea (3 g) is weighed and added to each replicate and stirred. The mixture is heated to boil for 3 minutes and cooled down to room temperature in a water-filled basin. Each replicate containing precipitate is added a few drops of dilute NH4OH. If the drop does not form red coloration upon mixing with the solution, precipitation is considered complete.

Gravimetric Determination Of Nickel Dmg Alloys

Three clean sintered glass crucibles, labelled 1, 2 and 3 respectively, are placed in a dessicator using tongs and weighed separately. The crucibles are then attached to the mouth of filtering flasks which are connected to the aspirator. The supernatant liquid (100 mL) of the mixture is decanted through the respective crucibles and the mixture in each replicate is stirred before being filtered through the crucibles using suction (vacuum filtration) for about 10 minutes. All the red precipitate is made sure to have been transferred into the crucible. The precipitate is washed with a few portions of distilled water (10 mL) before being dried in the oven until constant weight. When the experiment is completed, the crucibles are washed and rinsed in oxalic acid to remove unwashed precipitate.

  • Results and Discussion

Gravimetric Analysis Of Ni(dmg)2

Overall, the experiment was conducted without any unfortunate incidents. A few errors occurred during the conduct of experiment, which will be explained further in the discussion section….CONTINUED

IMPORTANT!! Purchase to download the entire lab report below (11pages)

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Gravimetric determination of Nickel using Dimethylglyoxime
Gravimetric analysis is one of the most accurate analytical methods available. It is concerned with the determination of a substance by the process of weighing. The element to be determined is converted into a stable compound of definite composition and the mass of the compound is determined accurately. From this, the mass of element is calculated. The gravimetric analysis involves a) precipitation b) filtration c) washing of the precipitate and d) drying and weighing of the precipitate. Advantage:  Conducted with simple apparatus.  Interpretation of results is easy and readings are directly related to analyte amount.
Gravimetric determination of nickel using dimethylglyoxime Gravimetric analysis can be used to determine the nickel content of a nickel(II) salt. This can be achieved by precipitation of nickel as nickel dimethyl glyoxime by adding alcoholic solution of dimethyl glyoxime C4H6(NOH)2 and then adding a slight excess of aqueous ammonia solution:
H
H O H3C
2 H3C
N C C
H 3C
+ Ni2+ N O
H Dimethylglyoxime
pH >5
H 3C
O
O
N
N
C C
C
Ni N
N
C
CH3 + 2H+ CH3
O
O H Nickel(II) dimethylglyoximate
The above reaction occurs due to donation of the electron pairs on the four nitrogen atoms, not by electrons on the oxygen atoms. The reaction is performed in a solution buffered by either an ammonia or citrate buffer to prevent the pH of the solution from falling below 5. If the pH does become too low the equilibrium of the above reaction favors the formation of the nickel (II) ion, causing the dissolution of Ni (DMG) 2 back into the mother liquor.The complex, nickel(II) dimethylglyoximate, is filtered from the reaction mixture, dried and weighed. Nickel content is calculated stoichiometrically from the weight of the precipitate
FT-IR spectroscopy can be used forcharacterisation of the Nickel(II)
dimethylglyoximate complex Labwares, Chemicals and Reagents:
                 
500 cm 3 beaker sintered glass crucible Buchner flask and adapter Vaccum pump desiccator balance (preferably accurate to 0.001 g) weighing bottle hot plate Water bath measuring cylinders (10 cm 3 and 100 cm 3 ) thermometer stirring rod dropper oven Nickel(II) chloride (NiCl 2 .6H 2 O) dimethylglyoxime in ethanol (0.1 mol l –1 ) 2 mol l –1 hydrochloric acid 2 mol l –1 ammonia
Procedure 1. 2. 3. 4. 5. 6.
7. 8. 9. 10.
11.
Weigh approximately 0.1 g of hydrated nickel(II) chloride . Weigh the dry sintered glass crucible. Add about 4 ml of deionised water to a 100 ml beaker and transfer the bulk of the nickel salt to the water. Stir the mixture until the solid dissolves and add about 4 ml of 2 mol l –1 hydrochloric acid. Dilute the mixture with deionised water to about 40 ml. Heat the solution to 70–80°C on a water bath for ~10 min and add approximately 10 ml of 0.1 mol l –1 dimethylglyoxime in ethanol. Add 2 mol l –1 ammonia solution dropwise and with constant stirring until a permanent red precipitate is obtained. Add a further 2 ml of the ammonia solution to provide a slight excess. Heat the beaker and contents on a water bath for about 10 minutes Remove the beaker from the water bath and allow it to cool to room temperature . After precipitate has settled test the clear liquid for complete precipitation by adding a few drops of the dimethylglyoxime and ammonia solutions. Set up the filtration apparatus: sintered glass crucible, Buchner flask and adapter. Filter off the precipitate at the water pump and wash the precipitate with a several portions of deionised water. Dry the crucible and precipitate in the oven at 120 °C.
12. 13. 14. 15.
Remove from oven and once they have cooled to room temperature, reweigh the crucible and contents. Calculate the percentage by mass of nickel in the sample of the hydrated nickel(II) chloride. Calculate the theoretical percentage by mass of nickel in NiCl 2 .6H 2 O and compare this with the experimental value. Account for any difference. Carefully preserve the Ni(II)(DMG) 2 complex for studying FR-IR.
Precaution: Wear eye protection and if any chemical splashes on the skin, wash it off immediately. Hydrated nickel(II) chloride is harmful by inhalation and by ingestion. Wear gloves. Dimethylglyoxime in ethanol is irritating to the eyes and is highly flammable. 2 mol l –1 ammonia irritates the eyes.
Be concerned: • To quantitatively collect all the precipitate • To know the exact composition of precipitate • To avoid loss of material during the handling/processing of sample. • To determine mass accurately and precisely
Calculations for Reagent preparation 2 M HCL (50 ml):
0.1 M Dimethylglyoxime (50 ml):
Calculations for Nickel Determination:
Weight of Nickel(II)chloride salt
Weight of dry sintered glass crucible
Mass of sintered glass crucible + Nickel complex
Mass of dimethyl glyoxime nickel complex (g)
Mass of Nickel in _______ g of complex =
References : Books:  Textbook of macro and semimicro qualitative inorganic analysis by Vogel.  Methods of Quantitative Inorganic Analysis by Kodama, Kazunobu.  Principles of Chemical Analysis by Mohd. Marsin Sanagi, Azli Sulaiman, Wan Aini Wan Ibrahim. Research Articles:  Is There Ni in My Liquor? A Hands-On Laboratory Exercise for Relating Chemistry to Extractive Metallurgy, Damian W. Laird and David J. Henry J. Chem. Educ. 2013, 90, 1671−1674.  The gravimetric determination of nickel with dimethylglyoxime in the presence of copper. Claassen and L. Bastings. Anal. Chem., 1959, 165, 134.  The determination of nickel by precipitation with dimethylglyoxime. J. T. Minster, Analyst, 1946,71, 424-428.