Fyeahuniverse

^{Earth a desert compared to Europa?}

^{The Galileo Probe gathered data between 1995 and 2003 during its exploration of the Jovian system. It found that Europa posses a large amount of water, around twice or three times as much as Earth.}

^{(Image credit: Kevin Hand (JPL/Caltech), Jack Cook (Woods Hole Oceanographic Institution), Howard Perlam (UGS)}

Beneath their rugged exterior, some Martian rocks could be hiding life, scientists suspect. An examination of data gathered by NASA’s Mars Exploration Rover Opportunity reveals deposits that, on Earth, are only created by water moving through the rock.

^{Pure Water Ice & Minerals on Europa}

^{Jupiter’s moon, Europa has been found to have pure water ice. Through the use of the Galileo Spacecraft, this image has been snapped using the Near Infrared Mapping Spectrometer (NIMS). With it we can see that the areas appear bright (red, orange, yellow) are due to surface compositions of pure water ice, and mixtures of water and other minerals.}

^{(Image credit: NASA/JPL)}

^{Spirals on Mars?}

^{These intriguing spirals seen in the Athabasca Valles region of Mars were once thought to be a result of ice-related activity, but a new high-resolution image has let researchers conclude that they were created by lava.}

^{The rings range from 5 to 30 meters wide and were not revealed until the image was boosted in contrast to make them appear bolder, so that they can be seen in spite of the dust and pale colours.}

^{(Image credit: NASA/JPL/University of Arizona)}

image by Flickr/Cyberchemist

The Tollen’s Reagent is used to determine whether a solution contains an aldehyde or a ketone.

Dilute sodium hydroxide is added to aqueous silver nitrate, this gives silver oxide, sodium nitrate and water.

2 AgNO₃ (aq) + 2 NaOH (aq) → Ag₂O (s) + 2 NaNO₃ (aq) + H₂O (l)

Then, aqueous ammonia is added to the solution until it goes clear. This is due to the now silver ions existing as [Ag(NH₃)₂]⁺ complexes.

Ag₂O (s) + 4 NH₃ (aq) + 2 NaNO₃ (aq) + H₂O (l) → 2 Ag(NH₃)₂NO₃(aq) + 2 NaOH (aq)

The silver precipitates out onto the inside of the container, giving the notable silver mirror as seen above.