If the rate of browning was not the same for the applesandthe rate of browning was different for the acid-treated apples compared with the base-treated apples, then this would indicate that the pH (acidity, basicity) of the treatmentdidaffect the rate of the enzymatic browning reaction. In ...
While the subject of "Acids and Bases" was taught supported with laboratory experiments in the experimental groups, traditional approach was used in the control groups. The results of the post-test (KR-20=0.77), applied after the instruction, indicated that students, who performed experiments was...
Openstax, Chemistry 2e, Section 14.4 Brønsted-Lowry Acid and Bases. Tags Bronsted-LowryAcidsBasesArrhenius AcidHydrogen IonHydroxide IonDissociatesAqueous SolutionBroader DefinitionBrønsted And LowryProton DonorProton AcceptorHydronium IonChloride IonAmmonium IonConjugate Acid-base Pairs...
And, finally, the experiments had to be based on the level of understanding of primary school. As part of the experimental work, I conducted an experiment in qualitative analytical chemistry. First, I determined the acids and bases using indicators, and then I tried to prove each acid. There...
conceptions of students and their learning difficulties; the appropriate sequencing of topics; the correct use of analogies and examples; ways to address the central ideas, experiments, projects and problems that the teacher used during class; ingenious ways of evaluating student progress and ...
A variety of Lewis bases were combined with 9-BBN-NTf 2 to establish the requirements for the generation of borenium cations. Five different types of behavior were found, but the most interesting was the combination of Et 3 N, DABCO, 2,6-lutidine, or Ph 3 P=S which formed borenium ions...
33and was used as the starting point for our new intermolecular α-C–H amination of carboxylic acids. Several control experiments were conducted to interrogate the intermediates involved in this reaction (Fig.2a). Under the standard conditions, methyl phenylacetate failed to afford any α-...
We found that the use of appropriate ligand loading amount (5 mol% of 4,4′-di-tert-butyl-2,2′-bipyridine), mixed solvents (DMF/CH3CN) and combined inorganic bases (K3PO4 and Cs2CO3) is crucial to achieve the desired C–C bond formation reactions, affording the desired ketone ...
experiments (Fig.6a). Under the optimal reaction conditions, chiral aldehyde3agave product5ain 85% yield and with 73% ee. In the absence of the Lewis acid ZnCl2, both the yield and enantioselectivity of5adecreased. This indicates the possible formation of a Zn2+–Schiff base complex during ...
The alkylation of aromatic amines in the presence of inorganic bases is accelerated by a PT catalyst even if KHCO3 is the base. ArNRθ ions seem not to be involved. A novel type of mechanism for a PTC process is proposed.DOI: 10.1016/S0040-4039(01)80801-7 被...