Origin and abundance of the elements, Chemistry

 

ORIGIN AND ABUNDANCE OF THE ELEMENTS

The synthesis of elements needs nuclear reactions, of which the most important type is the fusion of two light nuclei to prepare one of higher mass and charge. The attractive strong interaction, which holds neutrons and protons together, operates only over very short distances (around 10-15 m) and is opposed at longer size by the electrostatic repulsion between positively charged protons. To get two nuclei close enough together for fusion needs enormously high energies, which are usually found only at high temperatures (above 107 K) in the interior of stars. Under such conditions the chemical properties of components are irrelevant, as no compounds may exist, atoms being in highly ionized states stripped of their electrons.

 

Gases thrown out by a supernova cool, and can subsequently be incorporated into new stars. The formation of planetary systems can be common in the Universe. Studies suggest that other planets and the Earth formed about the same time as the Sun. While the Sun formed at the center, chemical reactions in the cooler outer parts of the gas concentration produced solid particles, which collected under gravitational forces, first into small bodies known as planetesimals, and subsequently into the planets. In the outer parts of the Solar System temperatures were low enough to form 'ices' of water, carbon dioxide, solid methane and ammonia, which are constituents of the giant planets Saturn and Jupiter.

 

Posted Date: 7/23/2012 7:58:22 AM | Location : United States







Related Discussions:- Origin and abundance of the elements, Assignment Help, Ask Question on Origin and abundance of the elements, Get Answer, Expert's Help, Origin and abundance of the elements Discussions

Write discussion on Origin and abundance of the elements
Your posts are moderated
Related Questions
Explain about the Defect breakdown It is because of cracks and pores at the surface. Moisture from atmosphere can collect on the surface and result in breakdown. Glazing is


Given that dH for the reaction is -92.2 kJ mol-1, which is larger, the total bond dissociation energy of the reactants or the total bond dissociation energy of the products?

Define Product process problem in experimental design method In food product design, there are two different kinds of system problems - process and mixture problems - that shou

what is thermogavimatic analysis and their instumental

Liquid-liquid extraction is used to separate acetone and MIBK. A mixture of acetone and MIBK is fed to a mixing tank at a rate of 100 kg/min. Pure water is also fed to the tank and

Q. Mention the stages in product life cycle, at which sensory evaluation is used? Initial screening, product optimization, scale up and production are the stages in product lif

Comment on the validity of the following statements, giving reasons: (a) Thermodynamically an exothermic reaction is sometimes not spontaneous. (b) The entropy of steam is mo

preparation of iodoform

In lab, you're having fun along with buffers based onto a 0.1 M solution of sodium phosphate at pH7.0.  Into this system, there are three of pK A s as:  12.7, 7.21 and 2.12.