I would say the answer is A - a stars mass
The majority of stars in the galaxy, including our Sun, Sirius and Alpha Centauri A and B are all main sequence stars.
Mass is the key factor in determining the lifespan of a main sequence star, its size and its luminosity ( brightness)
Two characteristics define brightness: luminosity and magnitude. Luminosity is the amount of light that a star radiates. The size of the star and its surface temperature determine its luminosity. Apparent magnitude of a star is its perceived brightness, factoring in size and distance, while absolute magnitude is its true brightness irrespective of its distance from earth.
Answer:
i am sure its the last one
Answer: The empirical formula of the metal sulfide is 
.
Explanation:
Given: Mass of metal = 20.38 g
Mass of metal sulfide = 31.47 g
Moles is the mass of a substance divided by its molar mass.
So, moles of cobalt (molar mass = 59 g/mol) are as follows.
Moles of bromine (molar mass = 80 g/mol) are as follows.
Now, the ratio of number of moles of cobalt and number of moles of bromine are as follows.
Moles of Co : Moles of Br = 1 : 2
Hence, the empirical formula is .
Thus, we can conclude that the empirical formula of the metal sulfide is .
I believe this nuclide is potassium with the symbol K. Atomic number for an element remains constant no matter how the mass changes. From the periodic table, potassium has an atomic number of 19.
Answer:
I'm afraid not, the image is too blurry
