<span>Well it depends on percentage by what, but I'll just assume that it's percentage by mass.
For this, we look at the atomic masses of the elements present in the compound.
Cu has an atomic mass of 63.546 amu
Fe has 55.845 amu
and S has 36.065 amu
Since there are 2 molecules of Sulfur for each one of Cu and Fe, we'll multiply the Sulfur atomic weight by 2 to obtain 72.13 amu
So we have not established the mass of the compound in amus
63.546 + 55.845 + 72.13 = 191.521
That is the atomic mass of Chalcopyrite. and Iron's atomic mass is 55.845
So to get the percentage, or fraction of iron, we take 55.845 / 191.521
Which comes out to 29.15% by mass
Mass of the sample is not needed for this calculation, but since the question mentions it I would go ahead and check if the question isn't also asking for the mass of Iron in the sample as well, in which case you just find the 29.15% of 67.7g</span>
The Reaction is spontaneous when temperature is 430 K. Hence, Option (C) is correct.
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</h3><h3>
What is Spontaneous reaction ?</h3>
Reactions are favorable when they result in a decrease in enthalpy and an increase in entropy of the system.
When both of these conditions are met, the reaction occurs naturally.
Spontaneous reaction is a reaction that favors the formation of products at the conditions under which the reaction is occurring.
According to Gibb's equation:
ΔG = ΔH - TΔS
ΔG = Gibbs free energy
ΔH = enthalpy change = +62.4 kJ/mol
ΔS = entropy change = +0.145 kJ/molK
T = temperature in Kelvin
- ΔG = +ve, reaction is non spontaneous
- ΔG = -ve, reaction is spontaneous
- ΔG = 0, reaction is in equilibrium
ΔH - TΔS = 0 for reaction to be spontaneous
T = ΔH / ΔS
Here,
T = 500K
Thus the Reaction is spontaneous when temperature is 500 K.
Learn more about Gibbs free energy here ;
https://brainly.in/question/13372282
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Answer: The atomic weight of silver is 107.87 amu
Explanation:
Mass of isotope silver-107 = 106.91 amu
% abundance of isotope silver -107 = 51.84% = 
Mass of isotope silver-109 = 108.90 amu
% abundance of isotope silver-109 = 48.16% = 
Formula used for average atomic mass of an element :
![A=\sum[(106.91\times 0.5184)+(108.90\times 0.4816)]](https://tex.z-dn.net/?f=A%3D%5Csum%5B%28106.91%5Ctimes%200.5184%29%2B%28108.90%5Ctimes%200.4816%29%5D)
Thus atomic weight of silver is 107.87 amu
Answer:
The process by which an unstable nucleus emits one or more particles or energy in the form of electromagnetic radiation.
Explanation:
