Answer:
This is a correct answer. 2HCL + Fe = FeCl2 + H2
Thus problem is providing us with the mass of iron (III) oxide as 12.4 g so the moles are required and found to be 0.0776 mol after the calculations:
<h3>Mole-mass relationships:</h3>
In chemistry, we use mole-mass relationships in order to calculate grams from moles and vice versa. In this case, since we are given the mass of iron (III) oxide as 12.4 g one can calculate the moles by firstly quantifying its molar mass:

Then, we prepare a conversion factor in order to cancel out the grams and thus, get moles:

Learn more about mole-mass relationships: brainly.com/question/18311376
As the volume of a gas increases <em>at constant temperature</em>, the number of particle impacts per unit area decreases.
There is the same number of impacts, but they are spread over a larger surface area.
Thus, the number of impacts per unit area decreases.
The composition would be more "diluted" in a sense.