Quantitative Determination of Citric and Ascorbic Acid in Powdered Drink Mixes: A High School or General Chemistry Experiment

2004 ◽  
Vol 81 (10) ◽  
pp. 1479 ◽  
Author(s):  
Samuella B. Sigmann ◽  
Dale E. Wheeler
Keyword(s):  
High School ◽  
General Chemistry ◽  
Ascorbic Acid ◽  
Quantitative Determination ◽  
Chemistry Experiment

ADENOHYPOPHYSEAL LH CONTENT IN NORMAL, ANDROGEN-STERILIZED AND PROGESTERONE-PRIMED STERILE FEMALE RATS

1962 ◽  
Vol 39 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Roger A. Gorski ◽  
Charles A. Barraclough
Keyword(s):  
Ascorbic Acid ◽  
Electrical Stimulation ◽  
Quantitative Determination ◽  
Median Eminence ◽  
Hypothalamic Stimulation ◽  
Female Rats ◽  
Rat Pituitary ◽  
Gland Content ◽  
Stimulation Of

ABSTRACT We have previously suggested that the failure of the androgen-sterilized, persistent-oestrous rat to ovulate, following electrical stimulation of the median eminence structures of the hypothalamus, is due to an insufficiency in adenohypophyseal LH concentration. Using the ovarian ascorbic acid technique for quantitative determination of pituitary LH content, the present studies have demonstrated that the sterile rat pituitary gland contains one-third the LH content of the normal prooestrous gland. Furthermore, not only does progesterone priming of this persistent-oestrous rat result in a 75 % increase in LH concentration, but on hypothalamic stimulation sufficient LH is released to induce ovulation. The decrease in LH concentration which accompanies ovulation in the progesterone-primed, sterile rat is approximately 45 % of the total gland content as compared with a 51 % decrease in pituitary content in the normal cyclic rat.

A Master Class in Dimensional Analysis: the Universal Gas Constant

2018 ◽  
Author(s):  
john andraos
Keyword(s):  
Physical Chemistry ◽  
High School ◽  
General Chemistry ◽  
Dimensional Analysis ◽  
Undergraduate Students ◽  
Microsoft Excel ◽  
Energy Unit ◽  
Spreadsheet Program ◽  
Volume Unit

We present a spreadsheet-assisted exercise using Microsoft Excel software for the<br>determination of the universal gas constant, R, in 35,712 different units. This large<br>number of units arises from a simple enumeration of possible pressure-volume unit<br>combinations and energy unit combinations covering SI (metric), Imperial (British), and<br>American units. In turn, various units for force and area used for defining pressure, and<br>various units for force and distance used for defining energy are explored. This<br>presentation serves as an excellent exercise for high school and undergraduate students to<br>master the skill of dimensional analysis, unit conversions, and basic combinatorics in<br>general chemistry and physical chemistry courses. Instructors can also use the described<br>exercise of constructing conversion matrices to train students in how to efficiently use the<br>Microsoft Excel spreadsheet program.

Rapid Screening Procedure for the Determination of Preservatives in Ground Beef: Sulfites, Benzoates, Sorbates, and Ascorbates

1976 ◽  
Vol 59 (4) ◽  
pp. 766-769
Author(s):  
Albert B Karasz ◽  
John J Maxstadt ◽  
Juergen Reher ◽  
Frank Decocco
Keyword(s):  
Ascorbic Acid ◽  
Quantitative Determination ◽  
Sodium Sulfite ◽  
Limit Of Detection ◽  
Ground Beef ◽  
Rapid Screening ◽  
Sodium Ascorbate ◽  
Potassium Sorbate ◽  
Large Numbers

Abstract A procedure is described for the examination of large numbers of ground beef samples for the 4 most commonly used preservatives. A single sample solution is prepared and aliquots are taken for the various tests. Sulfite is determined colorimetrically with acid-bleached p-rosaniline. Ascorbic acid is titrated with 2,6-dichloroindophenol. Benzoic and sorbic acids are measured by ultraviolet absorption. Negative samples are rapidly sorted out in this procedure and positive samples are completed for quantitative determination of the preservative. Recoveries are 95% for sodium sulfite, 103% for sodium benzoate, 90% for potassium sorbate, and 81 % expected recovery for sodium ascorbate. The limit of detection is 0.005% for potassium sorbate, and 0.01% for the 3 other preservatives.

A general chemistry experiment for the determination of the oxygen content of air

1981 ◽  
Vol 58 (10) ◽  
pp. 804 ◽  
Author(s):  
James P. Birk ◽  
Larry McGrath ◽  
S. Kay Gunter
Keyword(s):  
General Chemistry ◽  
Oxygen Content ◽  
Chemistry Experiment

Extraction and quantitative determination of ascorbic acid during different maturity stages of Rosa canina L. fruit

2008 ◽  
Vol 21 (4) ◽  
pp. 300-305 ◽  
Author(s):  
Saeed Nojavan ◽  
Faezeh Khalilian ◽  
Fatemeh Momen Kiaie ◽  
Atyeh Rahimi ◽  
Armin Arabanian ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Quantitative Determination ◽  
Rosa Canina ◽  
Maturity Stages
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