Answer:
C
Explanation:
Pb + H2O + O2 => Pb(OH)2
Number of oxygen atom on left = 3
Number of oxygen atom on the right = 2
To balance number of oxygen
Change the coefficient of Pb and H2O to two each
2Pb + 2H2O + O2 => 2Pb(OH)2
The coefficient of Pb and H2O is 2,2
Put up the answer choices
endothermic means absorbing heat
1 molecule of oxygen has 2 atoms.
So 2,25 molecules of oxygen have 2 x 2,25 atoms.
2 x 2,25 = 4,5 atoms
There are 4,5 atoms in 2,25 molecules oxygen.
