Answer: D. They show that neither theory is complete and entirely correct.
Explanation:
Theory is the set of rules and principles that describe and explain a particular phenomenon (the existence of the moon in this case) and is subject to changes as new evidence emerges that gives meaning to it.
In this sense, there are many theories about the Earth's moon formation and two of the "accepted" theories are described before the question. In addition, both theories explain in a certain way the reason why the Moon is predominantly composed of elements similar to those found on Earth.
However, both theories seem to be incomplete when trying to explain our Moon's origin.
Answer : The internal energy change is, -506.3 kJ/mol
Explanation :
Formula used :
or,
where,
= change in enthalpy = 
= change in internal energy = ?
= change in moles
Change in moles = Number of moles of product side - Number of moles of reactant side
According to the reaction:
Change in moles = 0 - 2 = -2 mole
That means, value of 
= 0
R = gas constant = 8.314 J/mol.K
T = temperature = 
Now put all the given values in the above formula, we get
Therefore, the internal energy change is -506.3 kJ/mol
The tool that can be used is a seismograph.
Answer:
37
Explanation:
Atomic mass is the sum of protons and neutrons in an atom.
One mole of any element is Avogadro's number, which is 6.02 * 10^23 atoms.
One mole of Calcium is equal to its atomic weight in grams, 1 mole Ca = 40.08 x 1000 mg = 6.02 * 10^23 atoms.
We have 8.6mg of Ca which means 8.6mg / 40,080mg = .00021457 of a mole of calcium.
Now multiply that by Avogadro's number which gives number of atoms = 0.00021457 * 6.02 * 10^23 atoms. So the answer is 1.292 * 10^20 atoms of Ca.
