How many moles of iodine vapor react with 1.00 mol of hydrogen gas?

1 mole

Explanation:

First thing's first we have to write out the chemical equation for the reaction.

Hydrogen + Iodine - -> Hydrogen Iodide

H2 (g) + I2 (s) → 2HI (g)

Upon observing the stoichiometry of the reaction, we can tell that;

1 mole of H2 reacts with 1 mol of I2

Answer;

1 mole

Explanation;

Iodine and hydrogen react according to the following equation to yield hydrogen iodide.

H2 (g) + I2 (s) = 2HI

Using the mole ratio; the mole ratio of H to I is 1: 1

Thus; 1 mole of hydrogen will require 1 mole of iodine to form 2 moles of hydrogen iodide.