9 просмотров
от (200 баллов) в категории Сериалы

Introduction to Buffers

A buffer is a solution that can resist pH change upon the addition of an acidic or basic components. It is able to neutralize small amounts of added acid or base, thus maintaining the pH of the solution relatively stable. This is important for processes and/or reactions which require specific and stable pH ranges. Buffer solutions have a working pH range and capacity which dictate how much acid/base can be neutralized before pH changes, and the amount by which it will change.

What is a buffer composed of?

To effectively maintain a pH range, a buffer must consist of a weak conjugate acid-base pair, meaning either a. a weak acid and its conjugate base, or b. a weak base and its conjugate acid. The use of one or the other will simply depend upon the desired pH when preparing the buffer. For example, the following could function as buffers when together in solution:

Acetic acid (weak organic acid w/ formula CH3COOH) and a salt containing its conjugate base, the acetate anion (CH3COO-), such as sodium acetate (CH3COONa)

Pyridine (weak base w/ formula C5H5N) and a salt containing its conjugate acid, the pyridinium cation (C5H5NH+), such as Pyridinium Chloride.

Ammonia (weak base w/ formula NH3) and a salt containing its conjugate acid, the ammonium cation, such as Ammonium Hydroxide (NH4OH)

Buffers are a class of solution-stabilizing molecules which existed long before contemporary lab technology. Natural buffer substances like bicarbonate and carbonic acid are manufactured by organisms and molecular interactions, functioning to maintain pH equilibrium.

After natural buffer systems were discovered, their balancing effects became indispensable in scientific exploration. Synthetic buffers were developed over decades to produce reliable reactions in experimental models, enhancing biochemical reactions and medicinal products.

New buffers are introduced every year, built from the fundamentals developed over a century ago. This article explores buffers beginning with the foundation which made them inseparable from biochemistry. We’ll then follow the construction and replacement of buffering systems among individual studies as procedures are continually refined.

Basic reagents are used in combination to produce the most potent buffer solutions. Once buffers transitioned into biochemistry, researchers began to establish what chemical mixtures were most productive for equalizing the pH of certain reactions.

Between the 1960s and 80s, a project for determining the best buffers resulted in a list that remains crucial in modern laboratories. “Good’s buffers” were produced or collected by Norman Good and his colleagues, and selected on a number of criteria that qualified application to research in the biological field. Some of the requirements were pKa between 6 and 8, high water solubility, stability and a lack of exchange with membranes or biochemical reactions. Good also prioritized substances that could be prepared easily and safely.

One of the lab world’s most valuable buffer agents, Tris – was first recognized by Good in the early 1960s. Known in therapeutics as THAM, Tris quickly adopted scientific roles. Tris and other reagents identified by Good continue to act as the equalizing agents within buffer mixtures by adjusting pH to a specified range.

How are Goggles Made

Goggles are a form of eye protection that is designed to shield the wearer from injuries to the eye due to hazardous conditions in the workplace, home, or other venues such as while playing sports. According to the National Institute for Occupational Safety and Health (NIOSH), approximately 2,000 work-related eye injuries requiring medical treatment are reported in the U.S. every day, the majority of which could have been prevented or been less severe had the proper eye protection been worn. Furthermore, the Department of Labor reports that eye injuries result in an estimated $300 million annually in lost production time, medical expenses, and workers’ compensation.

This article will describe how goggles are made and will discuss the common types of safety eyewear used as Personal Protection Equipment (PPE). You can learn more about other types of PPE in our related guides and articles, a list of which may be found at the end of this article.

Пожалуйста, войдите или зарегистрируйтесь чтобы ответить на этот вопрос.

1.3 тыс. вопросов

1.3 тыс. ответов

8 комментариев

3 тыс. пользователей

Похожие вопросы

0 ответов
спросил 30 Сен от dn567y81 (200 баллов) в категории ТВ передачи
0 ответов
спросил 16 Сен от dJnf6sd5d8 (200 баллов) в категории Сериалы
0 ответов
спросил 13 Сен от I676DDD (200 баллов) в категории Сериалы
0 ответов
спросил 07 Сен от E121III (220 баллов) в категории Сериалы
0 ответов
спросил 17 Сен от W123N (200 баллов) в категории Мультфильмы

Топ рейтинг сайтов! Статистика посещаемости сайтов Stata.Me
...