16 Questions
What is the role of theobromine in chocolates?
A diuretic
Which substance in chocolates is known for being a central nervous system stimulant?
Caffeine
What is the first step in the analytical process according to the text?
Formulate a question
Which type of sample is reduced in size to a few hundred grams and made homogeneous?
Laboratory Sample
What is the primary purpose of sampling in an analytical process?
To reduce sampling errors
What is the purpose of dry ashing in the analytical process?
To decompose organic substances
Which type of crucible is typically used in the analytical process?
Platinum-gold alloy crucible
What technique is utilized in sample preparation for liquid extraction?
Wet ashing
Which method involves the use of fuming HNO3 during sample preparation?
Microwave wet ashing
What is the purpose of derivatization in the analytical process?
To transform the sample for analysis
What is the purpose of choosing an amount of sample that minimizes variance in an analytical process?
To give more accurate and precise results
Why is it recommended to have at least 7 repetitions per analysis in an analytical process?
To improve the statistical confidence of the results
Which of the following is NOT a method used for dissolving inorganic materials in an analytical process?
Electrolysis of the sample
In sample preparation, which tool would be most suitable for crushing large samples into fine powder?
Ball mill
What is the purpose of using statistical methods to choose the number of replications in an analytical process?
To determine confidence intervals for the analysis
Why is reducing sampling errors important when selecting a random mixture for analysis?
To improve the accuracy of the analysis
Study Notes
- The analytical process for analyzing chocolates includes measuring the caffeine and theobromine content.
- Chemical Abstracts is a comprehensive source for finding articles in chemistry journals to select an analysis method.
- Sample preparation involves acquiring a bulk sample, reducing it to a laboratory sample, and then to an analytical sample for analysis.
- Sample processing techniques include decomposition methods like dry ashing and wet ashing, as well as sample preparation techniques like liquid extraction and solid phase extraction.
- To ensure precise results, it is important to choose the right sample size and number of replicates for analysis.
Learn about the steps in an analytical process for analyzing the caffeine and theobromine content in a chocolate bar. Understand how to select a method and measure the ingredients accurately.
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