Answer:
In the transition series, atomic size across a period decreases at first but then remains relatively constant.
The transition elements in a period show a steady increase in electronegativity.
Explanation:
In considering the transition series, we observe that atomic sizes of the elements decreases first and subsequently remain constant. The reason for the initial decrease in atomic size is the increase in nuclear charge across the period. After the first few elements in the period, the atomic size remains relatively constant due to shielding effect of the inner d electrons which opposes the increase in effective nuclear charge.
It is also observed that electro negativity increases smoothly across the period for the transition series. Consequently, the transition series become less electro positive across the period.
A pure copper cube has an edge length of 1.76 cm. How many copper atoms does it contain? (volume of a cube = (edge length)^3; density of copper = 8.96 g/cm^3 )
The Fischer esterification mechanism is examined in this question. The overall reaction is: Benzoic acid, C H 3 O H and H C l react to form a methyl ester, H 2 O and H C l. Benzoic acid is a carboxylic acid bonded to a benzene ring. Identify the results or mechanism of each step.
Answer:
See explanation and image attached
Explanation:
Fischer esterification is a type of reaction used to convert carboxylic acids to ester in the presence of excess alcohol and a strong acid which acts as a catalyst. Another final product formed in the reaction is water.
The mechanism for the fischer esterification of Benzoic acid and C H 3 O H in the presence of HCl as the catalyst is shown in the image attached to this answer.
The final products of the reaction are methyl benzoate, water and H^+ as shown in the image attached.
The methyl ester, water, and the acid catalyst (HCl) are byproducts of the Fischer esterification process, which involves protonation, nucleophilic attack, elimination, and deprotonation processes.
Carbonyl oxygen protonation: The carbonyl oxygen of the carboxylic acid (benzoic acid) is protonated by the acid catalyst (HCl) in the first step. The protonation of the carbonyl carbon increases its electrophilicity and promotes the alcohol's nucleophilic assault. Attack by the alcohol's nucleophilic oxygen (methanol, CH3OH) on the protonated carboxylic acid's carbonyl carbon results in the formation of a tetrahedral intermediate. The acid catalyst also helps with this phase. Elimination of water: In the following step, the water molecule must be removed from the tetrahedral intermediate. The hydroxyl group (-OH) from the carboxylic acid and a hydrogen from the hydroxyl group of the alcohol are removed to create this water molecule. Deprotonation: A deprotonation occurs after the removal of water.
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3 enzimas presentes en nuestro organismo e indique en que procesos actúan
Answer:
ATP asa, Helicasa, Proteasa, ARN polimerasa
Explanation:
Las enzimas son un tipo de biomoleculas que se corresponden con las proteinas.
Al momento de referirse a ellas, se utiliza la terminación asa.
ATPasa → Sintetizando ATP para el funcionamiento celular
Helicasa → Abre las hebras de ADN permitiendo el paso de la horquilla para el proceso de replicación de ADN.
Proteasas → Enzimas que degradan proteinas mal plegadas, rompen los enlaces peptídicos.
ARN polimerasa → Sintesis de ARN mensajero a partir de ADN en el proceso de la Transcripción. Se la puede conocer a veces, como primasa.
