Answer:
Explanation:
1.Scientists use a shared system for reporting measurements called the International System of Units (SI). We use common measurement systems because science involves a lot of replication to confirm results. The most common system used in science is the metric system.
2.m, kg, m^3
3. g value change
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:
A chemical reaction in which an uncombined element replaces an element that is part of a compound is called a simple substitution reaction or simple displacement reaction.
Explanation:
A simple substitution reaction or simple displacement reaction, called single-displacement reaction, is a reaction in which an element of a compound is substituted by another element involved in the reaction. The starting materials are always pure elements and an aqueous compound. And a new pure aqueous compound and a different pure element are generated as products. The general form of a simple substitution reaction is:
AB + C → A +BC
where C and A are pure elements; C replaces A within compound AB to form a new co, placed CB and elementary A.
So, in a Single replacement reaction an uncombined element replaces an element.
<u><em>A chemical reaction in which an uncombined element replaces an element that is part of a compound is called a simple substitution reaction or simple displacement reaction.</em></u>
As the number of electrons added to the same principal energy level increases, atomic size generally
C. Decreases.
C. a plane for forming a scientific hypotheses
