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//Chemistry : Bromine - What it is, how to extract it, what it's used for

Bromine is a halogen.

It can oxidise iodine, but is oxidised by chlorine and fluorine.

Adding chlorine to a bromide solution causes a redox reaction - the chlorine oxidises the bromide ions, taking their electrons and causing them to become bromine atoms.

The bromine atoms are displace and they are seperated from the bromide compound. The chlorine changes into chloride ions.

The chloride ions take the bromine's place and from a chloride compound.

On an industrial scale, it's harder to extract bromine in this way. Instead there is a more complex process:

Partially evaporate acidified sea water is warmed. (Sea water is slightly alkaline so this lowers the pH - sulphuric acid is used - as chlorine and bromine react better with water at higher pH levels.)

Chlorine is added. This is to displace bromine from the bromide ions in the sea water.

As bromine is very volatile, it evaporates and gives off bromine and water vapours when steam is blown through the reaction chamber.

The vapours condense into two immiscible layers.

The denser bromine layer is run off of the water layer above it.

This impure bromine is distilled and dried.

In addition, bromine has several uses once it has been distilled and dried. Bromine is used in the production of analgesics and sedatives. Silver bromide is also used in camera films.

#ocr chemistry salters b #ocr #chemistry #elements from the sea #revision aid #as level #revision

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//Electron Subshells//

There are 4 types of subshell : s, p, d, f.

Shell 1 contains one s subshell. It can hold 2 electrons.

Shell 2 contains one s, one p subshell. The p can hold 6 electrons.

Shell 3 contains s, p, and d. The d can hold 10 electrons.

Shell 4 onwards contains s, p, d and f. The f can hold 14 electrons.

3p and 4s overlap due to electron shells becoming closer together as you travel further away from the nucleus of an atom.

A subshell is known as an orbital - this is the shape of the space where there is the highest probability of an electron being found in an atom.

(image from http://chemistry.compendiarious.net)

#chemistry #electron subshells #ocr salters chemistry b #as level #revision

// Human Digestive System (Part One)//

The digestive system consists of the alimentary canal, or gut, which is a long tube from mouth to anus. It is about 9 metres long.

The mouth conducts mechanical digestion with the teeth and tongue to form a bolus, which is swallowed down the oesophagus via peristalsis (rhythmic contractions of the circular and longitudinal muscles in the gut wall). Chewing provides a larger surface area for enzymes to act upon, and also breaks the food down into smaller molecules.

The stomach wall releases gastric juices, hydrochloric acid and receives bile from the liver (via the bile duct) to chemically digest the food. Enzymes in gastric juice break down larger polypeptides into smaller dipeptides and monopeptides.

(diagram from wikipedia.org)

#human biology #as revision

//Iodine//

Iodine (I) is an element in Group 7, making it one of the halogens (along with Cl, F, At and Br).

It has an atomic number of 53 (number of protons).

Iodine is diatomic - it is usually written as I2.

Iodine is a solid at room temperature, dark purple in colour with a crystalline structure.

When exposed to heat, iodine sublimes- it changes state from a solid straight to a gas without becoming a liquid. This suggests that iodine has relatively weak intermolecular bonds - if it sublimes then this shows that relatively small amounts of energy are needed to break these bonds.

This sublimation produces a purple vapour, that can combine with air to form acid which will corrode the lungs if inhaled.

Iodine is relatively insoluble in water, as it forms non-polar molecules, but it does dissolve quite easily in organic solvents such as hexane. (This is true for the halogens in general.)

Iodine has a variety of oxidation states.

Iodine is used in solution to test for starch.

(Photo from wikipedia.org)

#chemistry #ocr salters b chemistry #elements of the sea #ES #as level

fuckyeahfluiddynamics

Two jets of sugar syrup collide and interact to form very different patterns. On the left, the two jets have a low flow rate and create a chain-like wake. The jets on the right have a higher flow rate and produce a liquid sheet that breaks down into filaments and droplets. The result is often likened to fish bones. (Photo credit: Rebecca Ing)

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scientiflix

One Step Closer to The Bionic Man

A shark attack survivor now knows what it feels like to be part bionic man. Twenty-three-year-old amputee Craig Hutto has volunteered to test a state-of-the-art prosthetic leg with powered knee and ankle joints.

rocketdigital-deactivated201510

Small asteroid 2012 BX34 skimmed past Earth today, January 27, 2012, with closest approach at about 15:25 UT, and it passed only about 59,044 km (36,750 miles) or about ~0.2 lunar distance (or 0.0004 AU) above the Earth’s surface. It was discovered just a few days ago by the Catalina Sky Survey in Arizona.

Above is an animation created by image from Ernesto Guido, Giovanni Sostero & Nick Howes from the Remanzacco Observatory in Italy. However, they took this series of images remotely from the GRAS Observatory, near Mayhill, New Mexico, using a 0.10-m f/5 reflector + CCD.

kny111

All-Sky Milky Way

This single image is able to show the entire sky, thanks to the truly dark sky of the Namibian savanna and to the absence of mountains. Only some small trees from the Tivoli farm are visible toward West.

smithsonianmag

The Highest Resolution Image of Earth Ever

This composite image uses a number of swaths of the Earth’s surface taken on January 4, 2012.

Photo courtesy of NASA/NOAA/GSFC/Suomi NPP/VIIRS/Norman Kuring

Ed note: Perfect for your desktop background. Click the photo for the 8000x8000 image. Check out our article on the previous photo titled The Blue Marble.

h/t Gizmodo

jthqp

Mars by Rosetta

On February 24, 2007, the ESA’s Rosetta spacecraft passed by Mars, the second of four planetary gravity-assist flybys on its long way to a 2014 rendezvous with comet Churyumov-Gerasimenkoy, getting close enough to take some very detailed pictures. That data wasn’t initially released by the mission leader, but they were finally made available late last year, including this frame-filling photo of Mars that Rosetta took as it approached the planet, using its main science camera, OSIRIS.

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14-billion-years-later-blog

Carbon Nanotubes While not being particularly new to science, carbon nanotubes remain one of the more interesting and versatile new materials. At their basic level all they are is an allotrope of carbon in the shape of a cylinder, typically made by rolling a single atom thick sheet known as graphene or by deposition of carbon atoms. They also occur naturally in flames. The importance of carbon nanotubes lies in their incredible strength but also incredibly low density which gives them a specific strength (force per unit area divided by density or N·m·kg−1 for short) ~310 times greater than high carbon steel. Carbon nanotubes also have the predicted ability to carry an electrical current density that is 1000 times that of traditional conductors such as copper along with also being superb thermal conductors. The longest carbon nanotube to date clocks in at 18.5 cm (7.3 inches or 84% the width of a soccer ball) with the greatest length to width ratio being 132,000,000:1. Images: 1, 2

realcleverscience

Old Mice Made “Young”—May Lead to Anti-Aging Treatments

I’ve written before about anti-aging advances, so this shouldn’t be shocking news for RCS regulars, but it is an example of what I’ve written before (e.g. here), namely, that we’re getting closer to true anti-aging technologies and perhaps what DeGrey calls the “longevity escape velocity,” the point at which we can extend our lives long enough to keep extending it indefinitely with further advances (here).

As the article notes, it’s too soon to know if this (and other) anti-aging techniques will prove useful for humans - but there’s definitely a chance. Also, I was quite pleased to read that this was an advance in stem cell research, considering all the controversy and complaints about it. So, give it a bit of time. Major scientific advances don’t happen overnight. It needs intelligent and devoted people, funding, and perhaps a bit of luck.

(Hat tip to ohyeahdevelopmentalbiology for the link.)

RCS Highlights:

Aging mice can be made “young” again, according to findings one scientist initially found unbelievable.

The key is muscle-derived stem cells, which—like other stem cells—are unspecialized cells that can become any type of cell in the body. When injected with muscle stem cells from young mice, older mice with a condition that causes them to age rapidly saw a threefold increase in their life spans, said study co-author Johnny Huard, a stem-cell expert at the McGowan Institute for Regenerative Medicine in Pittsburgh.

Curious if these deficient stem cells contribute to aging, Huard and colleagues injected stem cells from young, healthy mice into the fast-aging mice about four days before the older animals were expected to die. To Huard’s astonishment, the treated mice lived an average of 71 days—50 more than expected, and the equivalent of an 80-year-old human living to be 200, he said. Not only did the animals live longer, they also seemed healthier, the scientists found.

The “drastic” results bore out with repeated experiments, leaving the scientists to wonder how exactly the stem cells were working their magic, Huard said… The scientists went back to the lab to test another idea: that stem cells secrete some kind of mysterious anti-aging substance. The team put stem cells from the fast-aging mice on one side of a flask and stem cells from normal, young mice on the other side. The two sides were separated by a membrane that prevented the cells from touching. Within days, the aging stem cells began acting “younger”—in other words, they began dividing more quickly. “We can conclude that probably normal stem cells secrete something we don’t know that seems to improve the defects in those aging stem cells,” Huard said. “If we can identify that, we have found an anti-aging protein that is going to be important” for people, said Huard…

But other scientists are cautious about how soon the discovery may help people delay the aging process or treat age-related disease…

Paul Frenette, a stem cell and aging expert at the Albert Einstein College of Medicine in New York, called the research “intriguing,” but said one of the messages for “patients is not to get too excited.” “You see all these clinics that are popping up all over the world—even in New York—where they’re injecting stem cells” into people to treat disease, even though such therapies have not been proven…

Huard could imagine a scenario in which some of a person’s stem cells are harvested at about age 20 and then injected back into his or her body at around age 50 or 55. Stem cell therapies do already exist for conditions such as incontinence and heart problems, so he thinks “we’re not that far [from applying] this approach clinically down the road.” But Huard warned that such a treatment would not mean a 55-year-old will suddenly look and feel 25 again. “The goal of doing this research is not to [be like a] movie star with a ton of money [who wants to] look great for the rest of their lives,” he said. “The goal is, if you delay aging, maybe you can delay Alzheimer’s or cardiovascular problems.” In other words, he said, such stem cell treatments would help people “age well.”

scipsy-blog

Basking Shark (Cetorhinus maximus) (via Australian Geographic)

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