Answer
im not quite sure but I think the answer is <em>D atom</em><em> </em>
Explaination
<span>The choices are as follows:
h2o + 2o2 = h2o2
fe2o3 + 3h2 = 2fe + 3h2o
al + 3br2 = albr3
caco3 = </span><span>cao + co2
The correct answers would be the second and the last option. The equations that are correctly balanced are:
</span> fe2o3 + 3h2 = 2fe + 3h2o
caco3 = cao + co2
To balance, it should be that the number of atoms of each element in the reactant and the product side is equal.
Answer:
Because scientists call vaccines reagents.
Answer:
0,0,0,0
Explanation:
The formal charge formula:

So:
Hydrogen: 1 elec. of valence and shares two electrons with the O

Oxygen: 6 elec. of valence, 2 lone pairs and shares two electrons with the H and two with the F

Fluorine: 7 elec. of valence, 6 lone pairs and shares two electrons with the O

Oxygen: 6 elec. of valence, 3 lone pairs

Note: the dative bond between F and the second O doesn't count as shared electrons.