The image in the picture is a comet. what characteristic best identifies it as a comet?
a) comets are streaks of light.
eliminate
b) comets are larger than asteroids.
c) comets enter the earth's atmosphere.
d) comets develop a fuzzy, cloud-like shell called a coma, as well as a tail.

Comets develop a fuzzy, cloud-like shell called a coma, as well as a tail.

Explanation:

This feature of a comet develops when the celestial body passes close to a star such as the sun. The ice around the nucleus of the comet sublimates forming the coma around the comment (when hit by light photons as observed from the earth). The tails are also formed by the ice being pushed a bit behind the comet by light pressure.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.