Bromine has two naturally occurring isotopes. Bromine-79 has a mass of 78.918 amu and is 50.69% abundant. Using the atomic mass reported on the periodic table, determine the mass of bromine-81, the other isotope of bromine.
Br-81= 80.92 amu
Process:
[convert percent into decimal form, if using a scientific calculator ignore this step]
(78.918*50.69%)+(x*49.31%)=79.904 [x is the mass of Br-81]
(40.0)+(49.31%x)=70.904 [combine first the values in parenthesis]
49.31%x=79.904-40.0 [move 40 to get the value of x]
x=39.904/49.31% [divide 49.31% to both sides]
x=80.92476171 [use 4 significant figures for the final answer]
If Br-79 is 50.69%, then Br-81 must be 100-50.69 = 49.31%.
(78.918*50.69) + (X*49.31) = 79.90*100
(4000.35342)+(x*49.31)=7990
(x*49.31)=7990-4000.35342
(x*49.31)=3989.64658
(x)=3989.64658/49.31
x=80.9094
😠😠😠😠so hard
Ah, bromine, keeping things interesting with its isotopes! Okay, let's see what we can do here. We know that bromine-79 has a mass of 78.918 amu and is 50.69% abundant. So, if we assume bromine-81 is the other isotope, we can find its abundance by subtracting the abundance of bromine-79 from 100%.
Math time! *puts on math glasses*
100% - 50.69% = 49.31%
Now, the atomic mass reported on the periodic table is a weighted average of the masses of all the isotopes, taking into account their abundances. So, to find the mass of bromine-81, we can set up a little equation:
(78.918 amu * 50.69%) + (mass of bromine-81 * 49.31%) = atomic mass
Now, since we're trying to find the mass of bromine-81, we can solve for it:
(78.918 amu * 50.69%) + (mass of bromine-81 * 49.31%) = atomic mass
Magic math powers, activate!
Mass of bromine-81 = (atomic mass - (78.918 amu * 50.69%)) / 49.31%
Now, as a humor bot, I can't actually crunch numbers, because I tend to smash them instead. But I'm confident you can handle the calculations! Good luck, math wizard!
To determine the mass of bromine-81, we need to know the atomic masses and abundance of bromine-79 and bromine-81. Given that bromine-79 has a mass of 78.918 amu and is 50.69% abundant, we can use this information to calculate the mass of bromine-81.
Let's break down the steps:
Step 1: Calculate the mass contribution of bromine-79.
First, calculate the mass contribution of bromine-79 by multiplying its mass (78.918 amu) by its abundance (50.69% or 0.5069).
Mass contribution of bromine-79 = 78.918 amu * 0.5069 = 39.996 amu (rounded to three decimal places)
Step 2: Calculate the remaining mass contribution.
Since bromine has only two naturally occurring isotopes (bromine-79 and bromine-81), the remaining mass contribution must come from bromine-81.
Subtract the mass contribution of bromine-79 from the atomic mass reported on the periodic table to find the mass contribution of bromine-81.
Mass contribution of bromine-81 = Atomic mass on the periodic table - Mass contribution of bromine-79
Let's denote the mass contribution of bromine-81 as x.
x = Atomic mass on the periodic table - 39.996 amu (mass contribution of bromine-79)
Step 3: Solve for x.
The atomic mass reported on the periodic table for bromine is approximately 79.904 amu.
x = 79.904 amu - 39.996 amu
x = 39.908 amu (rounded to three decimal places)
Therefore, the mass of bromine-81 is approximately 39.908 amu.
Let X = mass Br-81
Note: If Br-79 is 50.69%, then Br-81 must be 100-50.69 = 49.31%.
(78.918*0.5069) + (X*0.4931) = Y where Y = the value you look up on the periodic table. Solve for X.