What are the 4 most abundant minerals in the continental crust? What percentage do these 4 makeup of the total?
1 answer:
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Answer:
The correct answer is option C.
Explanation:
1.0 g sample of a cashew :
Heat released on combustion of 1.0 gram of cashew = -Q
We have mass of water = m = 1000 g
Specific heat of water = c = 4.184 J/g°C
ΔT = 30°C - 25°C = 5°C
Heat absorbed by the water : Q
Heat released on combustion of 1.0 gram of cashew is -20,920 J.
3.0 g sample of a marshmallows :
Heat released on combustion of 3.0 g sample of a marshmallows = -Q'
We have mass of water = m = 2000 g
Specific heat of water = c = 4.184 J/g°C
ΔT = 30°C - 25°C = 5°C
Heat absorbed by the water : Q'
Heat released on 3.0 g sample of a marshmallows= -Q' = -41,840 J
Heat released on 1.0 g sample of a marshmallows : q
Heat released on combustion of 1.0 gram of marshmallows -13,946.67 J.
-20,920 J. > -13,946.67 J
The combustion of 1.0 g of cashew releases more energy than the combustion of 1.0 g of marshmallow.
Answer:
ΔG° = -118x10³ J/mol
Explanation:
The two half-reactions in the cell are:
Oxidation half-reaction:
Co(s) → Co²⁺(aq) + 2e⁻; E° = -0,28V
Reduction half-reaction:
Cu²⁺(aq)+2e⁻ → Cu(s); E° = 0,34V
The E° of the cell is defined as:
Replacing:
0,34V - (-0,28V) = 0,62V
It is possible to obtain the keq from E°cell with Nernst equation thus:
nE°cell/0,0592 = log (keq)
Where:
E°cell is standard electrode potential (0.62 V)
n is number of electrons transferred (2 electrons, from the half-reactions)
Replacing:
0,62V×2/0,0592 = log (keq)
20,946 = log keq
keq = 8,83x10²⁰≈ 5,88x10²⁰
ΔG° is defined as:
ΔG° = -RT ln Keq
Where R is gas constant (8,314472 J/molK) and T is temperature (298K):
ΔG° = -8,314472 J/molK×298K ln5,88x10²⁰
<em>ΔG° = -118x10³ J/mol</em>
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I hope it helps!