# Question #9f7ef

Jun 6, 2017

Q1. The minimum molecular mass of the compound is 330 u. Q2. There are 3 atoms of $\text{N}$ and 1 atom of $\text{S}$ per atom of $\text{Na}$.

#### Explanation:

Q1. Minimum molecular mass

There must be at least one atom of $\text{Na}$ in methyl orange (MeO).

∴ The minimum molecular mass (MMM) is

$\text{MMM" = 1 color(red)(cancel(color(black)("atom Na"))) × (22.99 color(red)(cancel(color(black)("u Na"))))/(1 color(red)(cancel(color(black)("atom Na")))) × "100 u MeO"/(7 color(red)(cancel(color(black)("u Na")))) = "330 u MeO}$

Q2. Atoms of $\text{N}$ and $\text{S}$.

$\text{Mass of N" = 330 color(red)(cancel(color(black)("u MeO"))) × "12.8 u N"/(100 color(red)(cancel(color(black)("u MeO")))) = "42 u N}$

$\text{Atoms of N" = 42 color(red)(cancel(color(black)("u"))) × "1 atom N"/(14.01 color(red)(cancel(color(black)("u")))) = "3 atoms N}$

$\text{Mass of S" = 330 color(red)(cancel(color(black)("u MeO"))) × "9.8 u S"/(100 color(red)(cancel(color(black)("u MeO")))) = "32 u S}$

$\text{Atoms of S" = 32 color(red)(cancel(color(black)("u"))) × "1 atom S"/(32.06 color(red)(cancel(color(black)("u")))) = "1 atom S}$