Question

Naturally occurring Indium has two isotopes.

4.28
%
4.28
%
of the atoms are
Indium
−
113
Indium
-
113
(
113
In
113
In
) with a mass of
112.9

u
112.9

u
and
95.72
%
95.72
%
of the atoms are
Indium
−
115
Indium
-
115
(
115
In
115
In
) with a mass of
114.9

u
114.9

u
. Calculate the average atomic mass of Indium with the correct number of significant figures.

Answer 1

Average Molar mass is 114.8u

Step-by-step explanation:

» From the formula of average Relative Atomic Mass [ RAM ]

`{ \rm{RAM = \sum ((isotopic \: mass * \%abundance))/(100) }} \\`

» We have two isotopes of Indium,

• Indium-113, mass » 112.9u, % » 4.28%
• Indium-115, mass » 114.9u, % » 95.72%

`{ \tt{RAM = \frac{ \blue{(112.9 * 4.28)} + { \green{(114.9 * 95.72)}}}{100} }} \\ \\ { \tt{RAM = (11481.44)/(100) }} \\ \\ { \underline{ \underline{ \tt{ \: RAM = 114.8\: }}}}`