Answer:
No, it is not enthalpy favored since the chemical system gains energy.
Explanation:
The dissolution of ammonium nitrate in water is an endothermic process.
Endothermic process requires the system to gain energy to can dissolve the particles in water.
So, the reaction is not enthalpy favored.
Answer: c. elements in the same row of the periodic table
Explanation: It kind of represents a graph of the periodic table
Answer:
c
Explanation:
the rate of a forward process must be exactly balanced by the rate of the reverse process.
Answer:
A. there is an isotope of lanthanum with an atomic mass of 138.9
Explanation:
By knowing the different atomic masses of both Lanthanum atoms, we can not tell anything about their occurence in nature. Therefore, all the last three options are incorrect. Because, the atomic mass does not tell anything about the availability or natural abundance of an element.
Now, the isotopes of an element are those elements, which have same number of electrons and protons as the original element, but different number of neutrons. Therefore, they have same atomic number but, different atomic weight or atomic masses.
Hence, by looking at an elements having same atomic number, but different atomic masses, we can identify them as isotopes.
Thus, the correct option is:
<u>A. there is an isotope of lanthanum with an atomic mass of 138.9.</u>
