I think this is what you wanted, so good luck!
Answer:
260.34g
Explanation:
First, you need to know what angelic acid is comprised of. It is written as C₅H₈O₂.
In order to solve for the mass of 2.6 moles of angelic acid, you need the mass of 1 mole of angelic acid. This can be found by adding the masses from the periodic table, like shown below:
5 carbon atoms = (5)(12.01g) = 60.05g
8 hydrogen atoms = (8)(1.01) = 8.08g
2 oxygen atoms = (2)(16) = 32g
angelic acid = 60.05 + 8.08 + 32 = 100.13g
Then, set up a basic stoichiometric equation and solve. The units should cancel out.

Uses of isotopes:
In agriculture,
C-14 is used to trace the path of photosynthesis.
In medicine,
Iodine -131 is used in the treatment of
goiter
Combine the number of its Protons and Neutrons and you will have its atomic mass.
Answer:
[HI] = 0.7126 M
Explanation:
Step 1: Data given
Kc = 54.3
Temperature = 703 K
Initial concentration of H2 and I2 = 0.453 M
Step 2: the balanced equation
H2 + I2 ⇆ 2HI
Step 3: The initial concentration
[H2] = 0.453 M
[I2] = 0.453 M
[HI] = 0 M
Step 4: The concentration at equilibrium
[H2] = 0.453 - X
[I2] = 0.453 - X
[HI] = 2X
Step 5: Calculate Kc
Kc = [Hi]² / [H2][I2]
54.3 = 4x² / (0.453 - X(0.453-X)
X = 0.3563
[H2] = 0.453 - 0.3563 = 0.0967 M
[I2] = 0.453 - 0.3563 = 0.0967 M
[HI] = 2X = 2*0.3563 = 0.7126 M