Answer: Option (D) is the correct answer.
Explanation:
Vapor pressure is defined as the pressure exerted by the vapors which are present on the surface of a liquid.
For example, vapor pressure of water at room temperature is 0.0313 atm.
On the other hand, the temperature at which the vapor pressure of a liquid equals atmospheric pressure is known as boiling point.
For example, boiling point of water at room temperature is
.
Thus, we can conclude that vapor pressure can be described as the pressure exerted by a gas above the surface of its liquid.
There are:
3.41 moles of C
4.54 moles of H
3.40 moles of O.
Why?
To solve the problem, the first thing that we need to do is to write the chemical formula of the ascorbic acid.

Now, we know that there are 100 grams of the compound, so, the masses of each element will represent the percent in the compound.
We have that:

To know the percent of each element, we need to to the following:

So, we know that for the 100 grams of the compound, there are:
40.92 grams of C
4.58 grams of H
54.49 grams of O
We know the molecular masses of each element:

Now, to calculate the number of moles of each element, we need to divide the mass of each element by the molecular mass of each element:

Hence, we have that there are 3.41 moles of C, 4.54 moles of H, and 3.40 moles of O.
Have a nice day!
21.69mL - 20.70mL = .99mL Fe
7.8 g / .99 mL = 7.9g/mL