Answer:- 14.0 moles of hydrogen present in 2.00 moles of
.
Solution:- We have been given with 2.00 moles of
and asked to calculate the grams of hydrogen present in it. It's a two step conversion problem. In first step we convert the moles of the compound to moles of hydrogen as one mol of the compound contains 7 moles of hydrogen. In next step the moles are converted to grams on multiplying the moles by atomic mass of H. The calculations are shown as:

= 14.0 g H
So, there are 14.0 g of hydrogen in 2.00 moles of
.
The best substance to heat up the fastest would be blue fire
Answer:
Option 4 with o-h in the most polar bond, since the two atoms in the bond have the greatest difference in electronegativity. This is assuming there are no other factors in other atoms bound to either of the elements in the bond.
Explanation: