Year 12 Chemistry Topics For An Essay

Virtual Collections include Special Issues and ACS Selects from ACS Journals. These collections reflect topics of current scientific interest and are designed for experienced investigators and educators alike. 

Below are our most recent collections from July 2015 to September 2015.

This virtual issue focuses on scientific and engineering advances related to Carbon Capture and Sequestration. With this virtual issue, we highlight the many ways in which chemists, materials scientists and chemical engineers are making a difference in meeting the grand challenge of safe, reliable, and affordable Carbon Capture and Sequestration technologies. Read More.

In this virtual issue Chemical Research in Toxicology, ACS Nano, and Nano Letters represent the forefront of research in the recently emerged field of nanotoxicology. The broad topics covered in this collection include the application of conventional in vitro toxicological approaches to assess the biological effects of nanomaterials, the development of new methods, studies of fundamental interactions between nanoparticles and molecular species, and vertebrate animal studies. Read More.

ACS Infectious Diseases is excited to publish its first special issue, a collection of work focused on “Virus Entry”. The papers in this collection highlight the multidisciplinary approaches required to understand the basic science underlying host–pathogen interactions as they pertain to virus entry. Read More.

In this second in a series of Forums on the activation of small molecules, a collection of articles is presented that focus on the interconversion of NOx species such as dinitrogen, nitrite, nitric and nitrous oxide, and ammonia that are highly relevant for the global nitrogen cycle. A pervasive theme is the role of these processes in global food and biofuel production, environmental pollution, and global climate. Read More.

This ACS Select virtual issue showcases transformations enabled by this intersection impact drug discovery, alternative energy schemes, and materials synthesis to name but a few. The topic of this joint virtual issue highlights the resurgent area of catalysis and organometallic chemistry with first row transition metals and includes papers that have appeared in the last year in Organometallics and ACS Catalysis. Read More.

This Virtual Special Issue of ACS Catalysis highlights “Catalysis in Singapore,” where a vibrant research and development community exists across several Agency for Science, Technology and Research (A*STAR) research institutes, universities and centers. This virtual collection presents a broad spectrum of research in Singapore, from new analytical techniques to new routes to novel materials, new materials as catalysts and catalyst supports, novel energy storage materials, enzyme catalysis and computational catalysis. Read More

The Drug Annotations series in the Journal of Medicinal Chemistry was launched in 2014. Drug Annotations cover a new approved drug or phase I, II, or III clinical candidate that is likely to provide or has provided a new treatment modality or significant patient benefit over existing therapy, with the authors outlining a case study of a synthetic or biological molecule, disease target(s), mechanism of action, and scientific rational for bringing the candidate to clinical trial. Read More

 

This virtual issue celebrates the 30th anniversary of Langmuir by collecting together some of the most important Langmuir articles published over its history. Here we are focusing on seminal advances that the Langmuir editors consider to have had the most influence in the community of surface science and colloid science that the journal was founded to serve. Read More

Together this group has published over 200 papers in Analytical Chemistry since 2014. We selected one article each from most members, covering a variety of subfields of analytical chemistry: nanoscale electro-chemistry, multiphoton spectroscopy, proteomics, sensors, droplet microfluidics, ion mobility mass spectrometry, to name just a few. Read More

Throughout 2015, we join our colleagues worldwide in a year-long celebration of the central role of light in science and technology: the International Year of Light. In this cross-journal virtual issue, we at ACS Photonics, The Journal of Physical Chemistry A and B, and Analytical Chemistry have compiled a diverse range of cutting-edge, light-based characterization and spectroscopy manuscripts that showcase how light continues to be at the forefront of some of the most exciting developments by ACS authors. Read More

This collection highlights computational methods and workflows relevant for the practice of medicinal chemistry.Computational methods with utility for medicinal chemistry have special requirements. The dominant theme of computational medicinal chemistry is helping to make better compounds and rationalize their properties.Read More

Biological processes are driven with outstanding precision by femtomoles of molecules acting in an environment subjected to the unique thermodynamic and kinetic constraints imposed by interfaces. New characterization tools and new chemistries are needed to understand biointerfacial processes, and to harness them for implementation in nanodevices. This research is at the intersection between the interfacial focus of Langmuir and the biomolecular and conjugation research featured in Bioconjugate Chemistry. Read More

As time has passed, the production of sodium hydroxide has become more technically and environmentally optimal due to technological advances. Three processes are used for the production of sodium hydroxide: the mercury, diaphragm and membrane processes. All three processes use saturated, purified brine as the starting material and produce chlorine gas, hydrogen gas and aqueous NaOH. Each of the processes produces chlorine gas at an inert anode by the oxidation of chloride ions:

2Cl(aq)→ Cl2(g) + 2e

In the mercury process, the cathode is a flowing liquid mercury which reduces sodium ions to sodium metal:

Na+(aq) + e→ Na(l)

The sodium dissolves in the mercury to produce an amalgam, which is mixed with water in a separate compartment. The sodium reacts with water to produce NaOH and hydrogen gas, and the mercury is recycled.

2Na(l) + 2H2O(l) → 2NaOH(aq) + H2(g)

Although this process produces high-purity NaOH, it also has high energy requirements and it is a two stage process. Both of these factors are industrially undesirable and require fossil fuel use, which leads to pollution. The most important factor which contributed to the change in production process is the unavoidable release of mercury into the environment. Avoiding mercury pollution was a major factor in changing the production process. Also, mercury is expensive, so replacing the lost mercury incurred a significant cost.

The diaphragm process, which developed at a similar time, has the same anode reaction as the mercury process. However, water is reduced at a steel mesh cathode to produce hydroxide ions and hydrogen gas. The anode and cathode compartments are separated by an asbestos diaphragm which allows Na+ ions to pass through, as they are attracted to the cathode, at which OH ions form. Therefore, a solution of NaOH(aq) is formed.

There are two factors which contributed to the phasing out of this process in many countries. First, even though it has lower energy requirements than the mercury process, it is a single-stage process, so the product was contaminated with about 2% NaCl. This level of salt is satisfactory for most applications. Furthermore, asbestos is carcinogenic, causing asbestosis in exposed workers. To overcome this health risk, the asbestos diaphragm was replaced by a diaphragm composed of a composite of metal oxides and a polymer.

The more modern process is the membrane process. In the membrane process, the anode and cathode reactions are the same as in the diaphragm process, but the anode and cathode compartments are separated by a special, selectively permeable polymer membrane (usually made of polytetrafluoroethylene, PTFE). It allows Na+ ions to pass through, but not anions or water. Therefore, Na+ ions can move from the anode compartment to the cathode compartment, where OH- ions are formed, to produce NaOH of high purity, removing the need for further purification. Hardly any chloride ions diffuse into the cathode electrolyte. Furthermore, because neither asbestos nor mercury are used, the process does not have environmental hazards associated with it. It is also the most energy efficient.

Assessment: Hence technological advances, in particular the development of the PTFE membrane, has overcome the technical and environmental issues associated with the older industrial NaOH production processes.

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