Answer: To show the number of atoms present.
Explanation: As in CO² (Carbon dioxide), there is a small 2 next to the symbol "O" (oxygen) to explain that there are two oxygen atoms.
<h2>Answer -
0.73%</h2>
14.6 .2
=
100 x
(Above is proportions I used to get the answer)
x = 0.73% which is the answer.
Answer: D. 19.9 g hydrogen remains.
Explanation:
To calculate the moles, we use the equation:
a) moles of 
b) moles of 
According to stoichiometry :
1 mole of require 1 mole of
Thus 0.0787 moles of 
require=
of
Thus is the limiting reagent as it limits the formation of product and acts as the excess reagent. (10.0-0.0787)= 9.92 moles of are left unreacted.
Mass of 
Thus 19.9 g of remains unreacted.
4 grams , mass cannot be created or destroyed. it has to be the same on both sides of the equation
