When did pangaea begin to break apart?
a.
20 million years ago
c.
250 million years ago
b.
100 million years ago
d.
2 billion years ago.

The correct answer is C. 250 million years ago

Explanation:

I know this question is 3 years old but I wanted to help future people

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.

it is a solid

explanation: