Which definition is correct?
a. a physical change creates a new substance because bonds are broken or formed
b. a chemical change occurs when the substance remains the same but the shape, or other physical characteristics change
c. a physical change can happen without changing any characteristics of the substance
d. a chemical change produces a new substance by breaking and forming new bonds

h let me think

atomic number of carbon is 6

electronic configuration of carbon is 1s²2s²2p²

orbital diagram of c is as shown here in the image.

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.