Answer: Most of the stars in the universe are main sequence stars — those converting hydrogen into helium via nuclear fusion. A main sequence star may have a mass between a third to eight times that of the sun and eventually burn through the hydrogen in its core. Over its life, the outward pressure of fusion has balanced against the inward pressure of gravity. Once the fusion stops, gravity takes the lead and compresses the star smaller and tighter.
Temperatures increase with the contraction, eventually reaching levels where helium is able to fuse into carbon. Depending on the mass of the star, the helium burning might be gradual or might begin with an explosive flash.
Answer:
Option C. 52.057
Explanation:
The following data were obtained from the question:
Isotope >> Mass number > Percentage
A (Cr-50) > 50 >>>>>>>>>> 4.3
B (Cr-52) > 52 >>>>>>>>>> 83.8
C (Cr-53) > 53 >>>>>>>>>> 9.5
D (Cr-54) > 54 >>>>>>>>>> 2.4
Average atomic mass =?
The average atomic mass of chromium, Cr can be obtained as follow:
Average atomic mass = [(Mass of A × A%) /100] + [(Mass of B × B%) /100] + [(Mass of C × C%) /100] + [(Mass of D × D%) /100]
Atomic mass of Cr = [50×4.3)/100] + [52×83.8)/100] + [53×9.5)/100] + [54×2.4)/100]
= 2.15 + 43.576 + 5.035 + 1.296
Atomic mass of Cr = 52.057
Therefore, the atomic mass of chromium, Cr is 52.057
The correct answer is C, too deep in the Earth to collect. Hope this helps!
<span>The thermodynamic determines the amount of chemical energy a substance has.</span>
Answer:
Gold is a metal, more specifically a transition metal, whereas Oxygen is a nonmetal, more specifically a reactive nonmetal. Using this information, you can compare and contrast metals, nonmetals, and metalloids.
Metals are:
Shiny
High melting point
Mostly silver or gray in color
Mostly solids at room temperature – Mercury (Hg) is a liquid at room temperature
Malleable – able to be hammered into a thin sheet
Ductile – able to be drawn/pulled into a wire
Good conductors of heat and electricity
Nonmetals are:
Dull
Low melting point
Brittle – break easily
Not malleable
Not ductile
Poor conductors of heat and electricity
Metalloids are:
Found on the “zig-zag” line on the Periodic Table of Elements
Have properties of both metals and nonmetals
Can be shiny or dull
Semiconductors – able to conduct electricity under certain conditions
Explanation:
Reccomend this site for questions llike these: https://ptable.com/#Properties
