Lo Qsea

Activities

First part
1. Why is it important to check up on theoretically scientific predictions by using variety of experiments?
A= Is important to check theories of scientists as well wecan see the progress of chemistry in our planet.
2. If we do not any experiments can we be sure that a theory on the elements, compounds or mixtures is absolute correct?
A=Not, because the theorymay not work with the elements, compounds or mixtures

Second part
1. Look for information in encyclopedias and on the internet about the discovery of helium and write down details like thediscovery, who discovered it, etc…
A=Helium is a chemical element with atomic number 2, the symbol I and atomic weight of 4.0026 standard. During a solar eclipse in 1868, French astronomer PierreJanssen observed a yellow spectral line in the sunlight that was hitherto unknown. Norman Lockyer observed the same eclipse and suggested that the line was produced by a new element, which he calledhelium, which both Lockyer and Janssen were awarded to the discovery of this element. In 1903 he found large reserves of helium in natural gas fields in the United States, with the increased productionof helium in the world. The Helium is the second lightest element and the second most abundant in the observable universe, accounting for 24 % of the mass of the elements present in our galaxy.2. Make a chart showing the most
Important characteristic of helium: the number of protons and neutrons in the nucleus, the density, physical state at room temperature and the applications of thiselement in our society
Characteristics of the Helium | |
Number of the protons | |
Number of the neutrons | |
The density | 0,1785 kg/m3 |
Physical state | Gas |
Applications of thiselements in our society | cryogenics, cooling superconducting magnets, MRI scanners, arc welding, silicon crystals, balloons and airships, in diving at great depth, quantum mechanics |

Ministry...