Answer:
the Germany scientist Alfred Wagner describes fold mountains that are found in The world are the same also geological similarity that occur between this continent are the same for example the rock that are found in brazil are the same of that of south africa.
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Answer :
Example of polar covalent molecules H-O-H(water), ammonia
Explanation:
The presence of intermolecular Hydrogen bonding makes the boiling point of water unexpectedly high, and the polar covalent nature makes it dissolve polar solute/compound
There are two naturally occurring isotopes of gallium: mass of Ga-69 isotope is 68.9256 amu and its percentage abundance is 60.11%, let the mass of other isotope that is Ga-71 be X, the percentage abundance can be calculated as:
%Ga-71=100-60.11=39.89%
Atomic mass of an element is calculated by taking sum of atomic masses of its isotopes multiplied by their percentage abundance.
Thus, in this case:
Atomic mass= m(Ga-69)×%(Ga-69)+X×%(Ga-71)
From the periodic table, atomic mass of Ga is 69.723 amu.
Putting the values,

Thus,

Rearranging,

Therefore, mass of Ga-71 isotope is 70.9246 amu.