Relative means you take the required amount from the actual amount which gives you the excess or abundance, its relative because you compare it to the required amount.
The percent abundance is the relative abundance as a percentage of the required amount.
Therefore % abundance= (abundance/required amount) X 100
The key difference is that percentages are standardised as a number out of 100 which allows you to compare them with other percentages without any calculations.
Hope that helps.
You can eliminate A, C, and D almost instantly if you know that engineers are construction workers. The answer is B.
Explanation:
According to the law of conservation of mass, mass can neither be created nor it can be destroyed. But it can be simply transformed from one form to another.
Therefore, when
is added to NaCl then the compound formed will have same mass as that of reactants.

Total mass of reactants is (169.87 + 58.44) g/mol = 228.31 g/mol
Total mass of products is (143.32 + 84.99) g/mol = 228.31 g/mol
Thus, we can conclude that mass of the new mixture will stay the same.
Answer:
Atomic number of this isotope = 77
Explanation:
Given that,
Mass number = 193
No of neutrons = 116
We need to find the atomic no of this isotope.
We know that,
Atomic mass = No of protons + No. of neutrons
Also, atomic no = no of protons
So,
Atomic mass = atomic no + No. of neutrons
⇒ Atomic no = Atomic mass - no of neutrons
Atomic no = 193 - 116
Atomic no = 77
Hence, 77 is the atomic no of the isotope.
There are globular and open star clusters, but there are no binary, eclipsing, or wobbling ones.