I hope this helps answer some of your questions.
Answer:
3 hydrogen bonds.
Explanation:
This is because the urea molecule has an oxygen atom bound with double bonds to the central carbon atom, and this oxygen can form a hydrogen bond with water, as well as both terminal amine groups that can also form a hydrogen bond each because of the lone pair of electrons on the nitrogen group.
<span>1.43g x (1 mole / 233g) x (6.022x10^23 particles / mole) = 3.70 x 10^ 21 particles</span>
to balance this equation, we will count the number of atoms of particular element in both sides, and then to balance the numbers we prefix the number so balanced equation for this is:
S + 2HNO3 --> H2SO4 + NO2