Answer: 39.948 grams
Explanation:
The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles Ar, or 39.948 grams
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.
Density is mass over volume. The density of iron is given in g/cm³
we have to first convert g/cm³ to kg/dL.
1000 g = 1 kg and 100 cm³ = 1 dL
the mass of 1 cm³ = 1 g
the mass of 100 cm³ / 1 dL = 100 g
then mass of 1 dL in kg is = 100 g / 1000 g/kg = 0.1 kg
volume of 0.1 kg is 1 dL
therefore density of iron is 7.86 g/cm³ x 0.1 kg/dL / g/cm³ = 0.786 kg/dL
volume of iron having mass 0.786 kg is 1 dL
then volume of iron having a mass of 4.62 kg is - 1 dL / 0.786 kg x 4.62 kg = dL
volume of iron is 5.88 dL
The answer is the sun and water
0.5 mole of Mg=12 grams= 0.5x atoms
