H20* SOO N34 Thats my answer
<h2>Answer : Law of conservation of mass</h2><h3>Explanation :</h3>
The law of conservation of mass states that in any reaction mass is neither created nor lost it has to remain constant in a system.
In this case, when the reaction setup was done in normal way the mass was lost in surrounding was not considered nor being calculated; whereas when the reaction was studied in a closed system where the gas was collected after the reaction the mass changes was noted down which helped to prove the point of law of conservation of mass and energy.
One can consider an example of soda can where the carbonated drink contains pressurized carbon dioxide gas. when opened the gas bubbles gets lost into the surroundings and we don't measure the mass changes. Instead if the soda can was opened in such a way where the gas evolved was measured then the mass changed would remain the same.
Answer : The 
for this reaction is, -88780 J/mole.
Solution :
The balanced cell reaction will be,
Here, magnesium (Cu) undergoes oxidation by loss of electrons, thus act as anode. silver (Ag) undergoes reduction by gain of electrons and thus act as cathode.
The half oxidation-reduction reaction will be :
Oxidation : 
Reduction : 
Now we have to calculate the Gibbs free energy.
Formula used :
where,
= Gibbs free energy = ?
n = number of electrons to balance the reaction = 2
F = Faraday constant = 96500 C/mole
= standard e.m.f of cell = 0.46 V
Now put all the given values in this formula, we get the Gibbs free energy.
Therefore, the for this reaction is, -88780 J/mole.
Answer:
In addition to mathematics, physics and astronomy, Newton also had an interest in alchemy, mysticism, and theology.
Because Wagner could not identify cause of continental drift
