Unit of measurement
ex: ft, in, etc.
Answer:
a)
b)
Explanation:
a) The reaction:

The free-energy expression:

![E=E_{red}-E_{ox]](https://tex.z-dn.net/?f=E%3DE_%7Bred%7D-E_%7Box%5D)
The element wich is reduced is the Fe and the one that oxidates is the Mg:

The electrons transfered (n) in this reaction are 2, so:


b) If you have values of enthalpy and enthropy you can calculate the free-energy by:

with T in Kelvin


Balancing of chemical equation is essential because of the law of conservation of mass, which states that the mass of a system can not be created or removed.
The second equation is balanced
This is because the number of elements of each atom in the product side equal the number of elements of each atom on the reactant side.
The first equation is not balanced

This is because there is 1 molecule of
on reactant side as compared to 3 molecules of 
To balance the equation we add a coefficient of 3 on sulphuric acid (
) and a coefficient of 3 on hydrogen (
)

0.0788 will be the number of moles of silver in coin.
<h3><u>How to find the number of moles?</u></h3>
A mole is the mass of a material made up of the same number of fundamental components. Atoms in a 12 gram example are identical to 12C. Depending on the material, the fundamental units may be molecules, atoms, or formula units.
A mole fraction shows how many chemical elements are present. The value of 6.023 x 10²³ is equivalent to one mole of any material (Avagadro's number). It can be used to quantify the chemical reaction's byproducts. The symbol for the unit is mol.
The number of moles formula is denoted by the following expression:
Number of moles = Mass of substance/mass of one mole
To view more about number of moles, refer to:
brainly.com/question/14080043
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