In the cores of extremely hot red giants, nuclear reactions convert helium to hydrogen carbon lead argon

Red giants produce "metals", i.e., heavier elements.

The first step is helium conversion into

carbon

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