Answer: 6.38 moles of
are needed to react with 2.55 mol of 
Explanation:
The balanced chemical reaction for the combustion of ethyne is:

According to stoichiometry:
2 moles of
require = 5 moles of 
Thus 2.55 mol of
require =
moles of 
Thus 6.38 moles of
are needed to react with 2.55 mol of 
Answer: The molarity of an HCl solution is 0.218 M if 43.6 mL of a 0.125 M NaOH solution are needed to titrate a 25.0 mL sample of the acid.
Explanation:
Given:
= 43.6 mL,
= 0.125 M
= 25.0 mL,
= ?
Formula used to calculate the concentration of acid is as follows.

Substitute the values into above formula.

Thus, we can conclude that the molarity of an HCl solution is 0.218 M if 43.6 mL of a 0.125 M NaOH solution are needed to titrate a 25.0 mL sample of the acid.
Among the choices provided, the statement that correctly describes the rusting process below is that "Oxygen was reduced over the course of this reaction" as <span> iron can't be the oxidizing agent, because it is the one being oxidized.
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Answer:
its because fibrinogen is a chemical substance that builds up at the wound and gets hard by the action of air to prevent bleeding