By being an alternative route to the reaction with a lower activation energy.
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>
Answer:
B
Explanation:
the candle is hot so the first energy form should be heat. u could now just eliminate the rest but for further notice. the heat melts the wax in the candle, which is a physical change but also the thread is burning out which is a chemical change then light follows
THe Answer is 105 J
hope this helps and please brainliest, I was first :)
