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.
Bohr changed the model of the atom by proposing that electrons travelled in circular orbits with specific energy levels.
Real quick, I will tell you why i think it does from a scientific point of veiw, but I dont know for sure.
The reason that the Earth goes through so much change on a regular basis is because of Gravity. What Gravity is doing is pulling objects to the Earth that it can reach (Which you probably knew) and so when it does this, it is pulling at the earths surface as well, causing constant change.
I hope this helps you!
Using the Bronsted-Lowry (B/L) Theory tell which is the acid and which the base in .... (c) [H+<span>] = </span>8.1x10-10M [OH-] = 1x10-14/8.1x10-10<span> = 0.12x10</span>-4<span> = 1.2x10</span>-5M ... (c) [OH-] = 4.5x10-7M [H+] = 1x10-14/4.5x10-7<span> = 0.22x10</span>-7<span> = 2.2</span>x10<span>-8</span><span>M</span>
Answer:
1360.0 g/mol
Explanation:
If there is one atom of cobalt in every molecule of cyanocobalamin its chemical formula must be
CoX₂, so there is 1 mol of cobalt for 1 mol of the compound. The molar mass of the cobalt is 59 g/mol. So, there is 59 g of cobalt in 1 mol of the cyanocobalamin and it represents 4.34% of the total mass, so:
0.0434m = 59
m = 1359.45 g of cyanocobalamin
The molar mass of the molecule is the mass divided by the number of moles (which is 1), so it is:
M = 1359.45 g/mol = 1360.0 g/mol
