Introducing a Simple Equation To Express Oxidation States as an Alternative to Using Rules Associated with Words Alone

Minkiewicz, Piotr; Darewicz, Małgorzata; Iwaniak, Anna

doi:10.1021/acs.jchemed.7b00322

Cited by 5 publications

(3 citation statements)

References 10 publications

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“…(1) is based on the relative electronegativities of the elements, expressed as oxidation numbers (e.g. Kauffman, 1986;Minkiewicz et al, 2018). When bonded to carbon, H is assigned an oxidation number of +1, and N, O, and S have oxidation numbers of -3, -2, and -2.…”

Section: Carbon Oxidation Statementioning

confidence: 99%

Uncovering chemical signatures of salinity gradients through compositional analysis of protein sequences

Dick¹,

Yu²,

Tan³

2020

Preprint

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Abstract. Thermodynamic influences on the chemical compositions of proteins in nature have remained enigmatic despite much work that demonstrates the impact of environmental conditions on amino acid frequencies. Here, we present evidence that the dehydrating effect of salinity is detectable as chemical differences in protein sequences inferred from (1) metagenomes and metatranscriptomes in regional salinity gradients and (2) differential gene and protein expression in microbial cells under hyperosmotic stress. The stoichiometric hydration state (nH2O), derived from the number of water molecules in theoretical reactions to form proteins from a particular set of basis species (glutamine, glutamic acid, cysteine, O2, H2O), decreases along salinity gradients including the Baltic Sea and Amazon River and ocean plume and in particle-associated compared to free-living fractions. However, the proposed metric does not behave as expected for hypersaline environments. Analysis of data compiled for hyperosmotic stress experiments under controlled laboratory conditions shows that differentially expressed proteins, as well as proteins coded by differentially expressed transcripts, are on average shifted toward lower nH2O. Notably, the dehydration effect is stronger for most organic solutes compared to NaCl. This new method of compositional analysis can be used to identify possible thermodynamic effects in the distribution of proteins along chemical gradients at a range of scales from biofilms to oceans.

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Section: Carbon Oxidation Statementioning

confidence: 99%

Uncovering chemical signatures of salinity gradients through compositional analysis of protein sequences

Dick¹,

Yu²,

Tan³

2020

Preprint

View full text Add to dashboard Cite

show abstract

“…12 With the obstacle constituted by the difficulty of chemistry concepts and the need to select only the most important, 13 supportive formulas to work with the commonly used rules were also suggested. 14 Secondly, students' results can be affected by the tasks' context which is carried by text. Added context on one hand brings relevance, 15 but on the other hand it increases the task's difficulty, as students need a certain level of reading literacy.…”

Section: Rusek Et Almentioning

confidence: 99%

To What Extent do Freshmen University Chemistry Students Master Chemistry Calculations?

Rusek

Vojíř²,

Bártová

et al. 2022

ACSi

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The research mapped chemistry-oriented university freshman students’ ability to solve chemical calculations. Their success was monitored based on several factors such as their faculty, field of studies, the type of calculation and the assignment type (word problem vs. formula). The results indicate a significant need to change the approach to teaching chemical calculations - the students were rather unsuccessful in the tasks. The obstacles they face include the ability to identify a problem, understand the concepts of calculation and appropriately adjust the correct use of the mathematical apparatus. These findings represent an impulse for teaching in upper-secondary school as well as to introductory university courses.

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“…6 Halkides argued, "Adopting oxidation numbers in biochemistry courses would serve to reinforce the concept and to integrate biochemistry more tightly into chemistry curriculum." 7 Currently, there are three commonly used methods, which can all be considered as chemical formula methods, [6][7][8][9][10][11][12][13] for calculating oxidation numbers. They are the molecular formula method, the Lewis formula method, and the structural formula method.…”

Section: Introductionmentioning

confidence: 99%

Fragmentation method for assigning oxidation numbers in organic and bioorganic compounds

Yuen

Lau

2021

Biochem Molecular Bio Educ

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Oxidation number (ON) is taught as an electron-counting concept for redox reactions in chemistry curriculum. The molecular formula method, the Lewis formula method, and the structural formula method have all been used to determine ON. However, the task of assigning ON still poses problems for some teachers and students. This paper explores a new method, the fragmentation method, which is a visual approach for counting the individual ON of any atom according to its structural formula. The critical step is to break the carbon-heteroatom bond into organic fragments and inorganic fragments. The individual ON of carbon atoms and heteroatoms can be determined by the bond cleavages in the organic and biological compounds. The mean ON of carbons can be calculated by the arithmetic mean of all individual ON of carbons in a molecule or molecular ion. The step-by-step operating procedures and examples are provided. When comparing corresponding molecules in organic conversions, the change of individual ON of atoms can be used as a tool for determining the number of transferred electrons. Furthermore, a reaction site can be identified by their changes of individual ON, chemical composition, and bond order in metabolic redox reactions.

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Introducing a Simple Equation To Express Oxidation States as an Alternative to Using Rules Associated with Words Alone

Cited by 5 publications

References 10 publications

Uncovering chemical signatures of salinity gradients through compositional analysis of protein sequences

Uncovering chemical signatures of salinity gradients through compositional analysis of protein sequences

To What Extent do Freshmen University Chemistry Students Master Chemistry Calculations?

Fragmentation method for assigning oxidation numbers in organic and bioorganic compounds

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