Answer:
The balanced chemical equation :

Explanation:
When calcium hydroxide reacts with hydrochloric acid it gives calcium chloride and water as a products. The chemical equation is given as:

According to question, solid calcium hydroxde is added to 38.0 mL of 0.410 M of HCl solution, so the chemical equation can be written as:

According to stoichiometry, when 1 mole of solid calcium hydroxide reacts with 1 mole of hydrochloric acid to gives 1 mole of aqueous calcium chloride and 1 mole of water.
You would think that the bag of nails would have more mass but their masses are identical. <span>If you were to put them both in a vacuum chamber and let them fall from a great height, they would fall the same speed. The vacuum chamber would suck all of the air out of the cotton balls, thus making it heavier and weigh the same as the bag of nails.
Hopefully this is helpful and makes sense.</span>