Answer:
E) None of the above
Explanation:
Metals react according to the activity series, thta is organized with the leats metals in in the bottom and the most reactive metals in the top. Most reactive metals displace less reactive metals in the compounds they are found.
in this series, Gold, Silver and Mercury are below Copper, this is, they are less reactive than Cu. this means none of them can displace it from its compounds.
E
θ
Cell
=
+
2.115
l
V
Cathode
Mg
2
+
/
Mg
Anode
Ni
2
+
/
Ni
Explanation:
Look up the reduction potential for each cell in question on a table of standard electrode potential like this one from Chemistry LibreTexts. [1]
Mg
2
+
(
a
q
)
+
2
l
e
−
→
Mg
(
s
)
−
E
θ
=
−
2.372
l
V
Ni
2
+
(
a
q
)
+
2
l
e
−
→
Ni
(
s
)
−
E
θ
=
−
0.257
l
V
The standard reduction potential
E
θ
resembles the electrode's strength as an oxidizing agent and equivalently its tendency to get reduced. The reduction potential of a Platinum-Hydrogen Electrode under standard conditions (
298
l
K
,
1.00
l
kPa
) is defined as
0
l
V
for reference. [2]
A cell with a high reduction potential indicates a strong oxidizing agent- vice versa for a cell with low reduction potentials.
Two half cells connected with an external circuit and a salt bridge make a galvanic cell; the half-cell with the higher
E
θ
and thus higher likelihood to be reduced will experience reduction and act as the cathode, whereas the half-cell with a lower
E
θ
will experience oxidation and act the anode.
E
θ
(
Ni
2
+
/
Ni
)
>
E
θ
(
Mg
2
+
/
Mg
)
Therefore in this galvanic cell, the
Ni
2
+
/
Ni
half-cell will experience reduction and act as the cathode and the
Mg
2
+
/
Mg
the anode.
The standard cell potential of a galvanic cell equals the standard reduction potential of the cathode minus that of the anode. That is:
E
θ
cell
=
E
θ
(
Cathode
)
−
E
θ
(
Anode
)
E
θ
cell
=
−
0.257
−
(
−
2.372
)
E
θ
cell
=
+
2.115
Indicating that connecting the two cells will generate a potential difference of
+
2.115
l
V
across the two cells.
Answer : The mass of oxygen formed must be 3.8 grams.
Explanation :
Law of conservation of mass : It states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.
This also means that total mass on the reactant side must be equal to the total mass on the product side.
The balanced chemical reaction will be,
According to the law of conservation of mass,
Total mass of reactant side = Total mass of product side
Total mass of 
= Total mass of 
As we are given :
The mass of 
= 25.3 grams
The mass of 
= 23.4 grams
So,
Therefore, the mass of oxygen formed must be 3.8 grams.
AXz
Explanation:
It is a chemical notation of nuclide
Here X is the symbol of the element
A is the mass number of element
A=n+p(sum of protons and neutrons)
Z is the atomic number.
For example, 12C6
Hers X is C, symbol of carbon
12 is the mass number and 6 is the atomic number of the carbon.
Answer:
P-positive
N-negative
E-no charge
