The mass of bromine in the oceans is about one three-hundredth that of chlorine. At standard conditions for temperature and pressure it is a liquid; the only other element that is liquid under these conditions is mercury. Molar mass of Br = 79.904 g/mol. Convert grams Bromine to moles or moles Bromine to grams. The formula weight is simply the weight in atomic mass units of all the atoms in a given formula. Using the chemical formula of the compound and the periodic table of elements, we can add up the atomic weights and calculate molecular weight of the. Bromine, chemical element, a deep red noxious liquid, and a member of the halogen elements, or Group 17 of the periodic table. Natural salt deposits and brines are the main sources of bromine and its compounds. Jordan, Israel, China, and the United States are major producers of bromine.
Bromine Protons
What is the average atomic mass of bromine? One isotope of bromine has an atomic mass of 78.92amu and a relative abundance of 50.69%. The other major isotope of bromine has an atomic mass of 80.92amu and a relative abundance of 49.31%.
1 Answer
The average atomic mass of Br is 79.91 u.
There are two ways to solve this problem.
Method 1
Let's assume we have 10 000 atoms of Br. Then 5069 atoms will have mass 78.92 u, and 4931 atoms will have mass 80.92 u.
Iodine Atomic Mass
Mass of the 5069 atoms = 5069 × 78.92 u = 400 000 u
Mass of the 4931 atoms = 4931 × 80.92 u = 399 000 u
Mass of 10 000 atoms = 799 100 u
Average mass of an atom =
Method 2
The average mass is the mass of each isotope multiplied by its percentage. Thus,
Average mass = 50.69 % × 78.92 u + 49.31 % × 80.92 u = 40.00 u + 39.90 u = 79.91 u
The second method is easier, but it doesn't explain intuitively why the answer is the average atomic mass.
Bromine Normal Phase
Here is a video which summarizes the steps needed to calculate average atomic mass.
Bromine Atomic Mass Number
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