Atomic Number 54 The element symbol is ,

(Be careful: the symbol must be written correctly.)
PLS HEL

a) 210.3 g/mol

b) 210.2 g/mol

c) 384.5 g/mol

Explanation:

First step we will calculate the molar masses of ; carbon atom, hydrogen atom and  oxygen atom in each .

Molar mass of dibenzyl ketone

Molar mass of dibenzyl ketone = ∑ molar masses of atoms in dibenzyl ketone

= carbon( 15 ) = 15 ( 12.0107 ) + oxygen ( 14 ) = 1 ( 15.999 ) + hydrogen(14) =14(1.00784)

= 210.26926 ≈ 210.3 g/mol

 Molar mass of benzil

Molar mass of Benzil =  ∑ molar masses of atoms in  Benzil

= carbon( 14) = 14(12.0107) + oxygen(2) = 2 ( 15.999) +  hydrogen(10) =10(1.00784)

= 210.2262 ≈ 210.2 g/mol

Molar mass of 2,3,4,5-

Molar mass  = ∑ molar masses of atoms

= carbon ( 29) = 29(12.0107) + oxygen (1) = 1( 15.999 ) + hydrogen(20) = 20(1.00784 )

≈ 384.5 g/mol