This question is describing the following chemical reaction at equilibrium:

And provides the relative amounts of both A and B at 25 °C and 75 °C, this means the equilibrium expressions and equilibrium constants can be written as:

Thus, by recalling the Van't Hoff's equation, we can write:

Hence, we solve for the enthalpy change as follows:

Finally, we plug in the numbers to obtain:
![\Delta H=\frac{-8.314\frac{J}{mol*K} *ln(0.25/9)}{[\frac{1}{(75+273.15)K} -\frac{1}{(25+273.15)K} ] } \\\\\\\Delta H=4,785.1\frac{J}{mol}](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5Cfrac%7B-8.314%5Cfrac%7BJ%7D%7Bmol%2AK%7D%20%2Aln%280.25%2F9%29%7D%7B%5B%5Cfrac%7B1%7D%7B%2875%2B273.15%29K%7D%20-%5Cfrac%7B1%7D%7B%2825%2B273.15%29K%7D%20%5D%20%7D%20%5C%5C%5C%5C%5C%5C%5CDelta%20H%3D4%2C785.1%5Cfrac%7BJ%7D%7Bmol%7D)
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The rock is limestone, I hope this helps!!
Answer:
43 mole
Explanation:
Given data:
Number of atoms of Li = 2.6× 10²⁵ atoms
Number of moles = ?
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
2.6× 10²⁵ atoms × 1 mole / 6.022 × 10²³ atoms
0.43 × 10² mole
43 mole
Answer:
15.89grams
Explanation:
The mass of a substance can be calculated from it's mole value by using the formula:
mole = mass/molar mass
According to this question, there are 0.250 moles of copper. Hence, the mass of copper can be calculated as follows:
Molar mass of Cu = 63.55g/mol
0.250 = mass/63.55
mass = 0.250 × 63.55
mass = 15.8875
Mass of Cu in 0.250mol is 15.89grams.