CHEM.8.C

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The student is expected to calculate percent composition of compound; and
1666 TEKS header image

Knowledge and Skills Statement

Science concepts. The student understands how matter is accounted for in chemical substance.

Glossary terms and definitions are consistent across kindergarten through high school in the TEKS Guide. The definitions are intended to give educators a common understanding of the terms regardless of what grade level they teach. Glossary definitions are not intended for use with students.

any material that has a definite chemical composition

a pure substance that is made up of two or more different elements in a specific ratio

substance that occupies space, has mass, and is composed of microscopic particles
 

Research

Hanson, Ruby. "Ghanaian Teacher Trainees’ Conceptual Understanding of Stoichiometry." Journal of Education and E-Learning Research 3, no. 1 (2016): 1–8. https://doi.org/10.20448/journal.509/2016.3.1/509.1.1.8

Summary:  An interpretive study on trainees’ conceptual understanding of chemical stoichiometry was carried out among 78 teacher trainees in their second year of study. The interpretation indicated that their learning of stoichiometry was basically through the use of picket fence (factor label), undefined strategies and algorithm. The trainees were found to have more persistent problems with conceptual interpretation as they were not able to fully translate word problems into mathematical equations regardless their algorithmic underpinnings. Neither did they understand fully, the law of conservation of matter.

Research

Wagner, Eugene P. "A Study Comparing the Efficacy of a Mole Ratio Flow Chart to Dimensional Analysis for Teaching Reaction Stoichiometry." School Science and Mathematics 101, no. 1 (2001): 10-22. doi:10.1111/j.1949-8594.2001.tb18185.x.

Summary:  Stoichiometry has long been a nemesis of students in general chemistry. Described here is a proportional reasoning methodology called the Mole Ratio Flow Chart (MRFC) that has been developed and used over the past 2 years in the investigator's general chemistry courses. A study was conducted in the spring 1999 and fall 1999 semesters in the Chemistry 1251 course to determine the relative efficacy of the MRFC compared to dimensional analysis for student performance and understanding of reaction stoichiometry.