For a reaction to occur, energy must be to break chemical bonds.

a. converted

b. released

c. absorbed

The correct answer is absorbed.

Explanation:

Bond formation is a type of exothermic process. In these reactions when two atoms come close to each other, energy is released in this process.

On the other hand, in the breaking of bond, energy is required because the atoms are to be separated from each other. This is a type of endothermic process. So, the energy must be absorbed.

Hence, the correct answer is absorbed.

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.