Moles = mass / molar mass
molar mass of O2 is 32
therefore moles = 72/32
= 2.25 moles
Answer:
Option D. 5.5
Explanation:
The equation is this:
2A + 6B ⇒ 3C
With the amounts that we were given, let's determine which is the <em>limting reactant</em>
2 A reacts with 6 B
4 A will react with ( 4 .6)/2 = 12B
I have 11 B, so the limiting is B
6 B react with 2 A
11 B will react with (11 .2 )/6 =3.66 A
I have 4 A, so A is the excess.
6 B produce 3 C
11 B will produce ( 11 .3)/6 = 5.5C
We’ll be using the equation:
dG = dH - TdS (replace ‘d’ with triangle)
I’m going to assume 0 degrees Celsius.
At 0 C (273 K):
dG = dH - TdS
dG = (285,400 J) - (273 K)(-137.14 J/K)
dG = 285,400 J + 37,439.2 J
dG = 322,839.2 J or 322.84 kJ
The dG of this reaction is +322.84 kJ. This reaction is not considered spontaneous.
This answer, in this instance, would be D. If the temperature used in the question is not 0 degrees C, replace the temperature that I used for calculation with the Kelvin temperature given in the problem (K = C + 273), and simplify to find the answer.
The answer is C. A, B, and C would depend on what type of electron it is.
