Question

What is the number of moles in 15.0 g AsH3?

Answer 1

We are given with the mass of Arsine ($AsH_{3}$

The mass of arsine is 15g

there is a relation between moles, mass and molar mass of any compound which is

$moles=\frac{mass}{molarmass}$

The molar mass of Arsine = atomic mass of As + 3X atomic mass of H

the molar mass of Arsine = 74.92 + 3X 1 = 77.92 g/mol

Let us calculate the moles as

$moles=\frac{15}{77.92}=0.192mol$