Gravimetric Determination of Calcium
Gravimetric Determination of Calcium
ABSTRACT
Determining the mass of a pure compound is a method of a gravimetric analysis. One of the gravimetric analyses is the precipitation; it is a method of separating the analyte from the unknown sample as a precipitate where it will be filtered and converted into a known composition that can be weighed to determine its mass (Skoog et al, 2013). Determining the mass of calcium by using gravimetric analysis was the objective of the experiment.
A 25 mL of unknown sample was used to analyze its calcium component. This sample was diluted with 25mL of distilled water in a beaker. It was converted into a soluble precipitate by adding 25 mL of ammonium oxalate solution and 15 g of solid urea. Since the solution is acidic, the Ca2+ and C2O42- were dissolved. By boiling the solution, the pH of the urea increases thus large, pure crystals of precipitate was able to obtain.
Subtracting the mass of the petridish alone from the mass of the petridish with CaC2O4 2H2O precipitate, one can get the mass of calcium oxalate dihydrate. And from that using stoichiometry, one can determine the mass of calcium. Based from what we have computed the resulted mass of calcium is 0.3267 grams.
I. INTRODUCTION
Gravimetric methods are quantitative methods that are based on determining the mass of analyte and one of the methods is the precipitation. Precipitation gravimetry involves converting analyte into a soluble precipitate where it will be filtered, washed, and converted to product of known composition by heat treatment, and then this will be weighed. This scientific report will focus more on being familiar with the gravimetric methods of analysis and determining the weight of calcium in the unknown sample.
The mass of calcium in an unknown sample can be determined by using gravimetric method. Precipitating the calcium with oxalate anion, C2O42-, will form a precipitate. Ca2+ (aq) + C2O42-(aq) → CaC2O4 2H2O (s). Wherein, it is soluble
ABSTRACT
Determining the mass of a pure compound is a method of a gravimetric analysis. One of the gravimetric analyses is the precipitation; it is a method of separating the analyte from the unknown sample as a precipitate where it will be filtered and converted into a known composition that can be weighed to determine its mass (Skoog et al, 2013). Determining the mass of calcium by using gravimetric analysis was the objective of the experiment.
A 25 mL of unknown sample was used to analyze its calcium component. This sample was diluted with 25mL of distilled water in a beaker. It was converted into a soluble precipitate by adding 25 mL of ammonium oxalate solution and 15 g of solid urea. Since the solution is acidic, the Ca2+ and C2O42- were dissolved. By boiling the solution, the pH of the urea increases thus large, pure crystals of precipitate was able to obtain.
Subtracting the mass of the petridish alone from the mass of the petridish with CaC2O4 2H2O precipitate, one can get the mass of calcium oxalate dihydrate. And from that using stoichiometry, one can determine the mass of calcium. Based from what we have computed the resulted mass of calcium is 0.3267 grams.
I. INTRODUCTION
Gravimetric methods are quantitative methods that are based on determining the mass of analyte and one of the methods is the precipitation. Precipitation gravimetry involves converting analyte into a soluble precipitate where it will be filtered, washed, and converted to product of known composition by heat treatment, and then this will be weighed. This scientific report will focus more on being familiar with the gravimetric methods of analysis and determining the weight of calcium in the unknown sample.
The mass of calcium in an unknown sample can be determined by using gravimetric method. Precipitating the calcium with oxalate anion, C2O42-, will form a precipitate. Ca2+ (aq) + C2O42-(aq) → CaC2O4 2H2O (s). Wherein, it is soluble
References: http://chemweb.chem.uconn.edu/teaching/chem-232/Laboratory_Manual/GA3_Ca_by_homo_precp_revLS1.pdf http://www.chm.uri.edu/jdwyer/chm212_fall_10/CHM212_Exp5_2010_Final.pdf http://jupiter.plymouth.edu/~jsduncan/courses/2011_Spring/Techniques/Labs/10-GravimetricDeterm.pdf http://www.ausetute.com.au/gravimetric.html Fundamentals of Analytical Chemistry by Skoog, West, Holler and Crouch VI. ACKNOWLEDGMENTS