Indium has an average atomic mass of 114.818 amu. One of its two isotopes has an atomic mass of 114.903 amu with a percent abundance of 95.70. What is the mass of the other isotope?

The atomic mass of second isotope is 112.926 amu.

Explanation:

Given data:

Average atomic mass of indium = 114.818 amu

Atomic mass of one isotope = 114.903 amu

Percentage abundance of 1st isotope = 95.70%

Mass of other isotope = ?

Solution:

First of all we will calculate the percentage abundance second isotope.

100 -  95.70% = 4.3%

percentage abundance of second isotope = 4.3%

Now we will calculate the mass if second isotope.

Average atomic mass of indium = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)  / 100

114.818 = (114.903×95.70)+(x×4.3) /100

114.818 =   10996.2171 + (x4.3) / 100

114.818×100 = 10996.2171 + (x4.3)

11481.8 -  10996.2171  = (x4.3)

485.583 = x

x = 485.583 /4.3

x = 112.926

The atomic mass of second isotope is 112.926.

the answer is 1260

you spend 7 hours in school for 1 school day with 5 school days in 1 school week with 36 school weeks in a school year.

7*5*36= 1260 it's all about multiplying