Data Given:
Change in Entropy = ΔH = 120.5 kJ = 1.20 × 10⁵ J
Temperature = T = 298 K
Change in Entropy = ΔS = 758.2 J/K
Using Formula,
ΔG = ΔH - T ΔS
Putting Values,
ΔG = (1.20 × 10⁵ J) - (298 K × 758.2 J/K)
ΔG = -1.059 × 10⁵ J
ΔG = -105.94 kJ
A) Molar mass gold ( Au) = 196.96 g/mol
1 mole Au ----------- 196.96 g
? moles Au ---------- 35.12 g
35.12 x 1 / 196.96
= 0.178 moles of Au
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b) 196.96 g --------------- 6.02x10²³ atoms
35.12 g ---------------- ( atoms ? )
35.12 x ( 6.02x10²³) / 196.96
2.114x10²⁵ / 196.96
= 1.07x10²³ atoms
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Answer : The value of 
is -24.9 kJ/mol
Explanation :
First we have to calculate the value of 'Q'.
The given balanced chemical reaction is,
The expression for reaction quotient will be :
In this expression, only gaseous or aqueous states are includes and pure liquid or solid states are omitted.
Now put all the given values in this expression, we get
Now we have to calculate the value of .
The formula used for is:
............(1)
where,
= Gibbs free energy for the reaction = ?
= standard Gibbs free energy = -28.0 kJ/mol
R = gas constant = 
T = temperature = 298 K
Q = reaction quotient = 3.375
Now put all the given values in the above formula 1, we get:
Therefore, the value of is -24.9 kJ/mol
Answer:
http://www.khalidshadid.com/uploads/3/9/2/0/3920808/raymond_chang-chemistry_10th_edition.pdf
Explanation:
http://www.khalidshadid.com/uploads/3/9/2/0/3920808/raymond_chang-chemistry_10th_edition.pdf
Answer is: c. 1.204 × 10²⁴ atoms
of carbon.
n(C) = 2 mol; amount of substance of carbon.
Na = 6.02·10²³ 1/mol; Avogadro constant (the number of constituent particles, in this example atoms, that are contained in the amount of substance given by one mole).
N(C) = n(C) · Na.
N(C) = 2 mol · 6.02·10²³ 1/mol.
N(C) = 12.04·10²³ = 1.204·10²⁴; number of carbon atoms in a sample.
