Question

An oxide of arsenic contains 3.26 g of arsenic and 1.04 g of oxygen. What is the empirical formula for this oxide?

Answer 1

The empirical formula for this oxide : As₂O₃

Further explanation:

Given

mass of Arsenic=3.26 g

mass of Oxygen = 1.04 g

Required

The empirical formula

Analysis

• find mole of elements
• determine the ratio of each element

Solution

mol of Arsenic(MW=74,9216 u) :

`\tt mol=(3.26)/(74,9216)=0.0435`

mol of Oxygen(MW=15.999 u) :

`\tt mol=(1.04)/(15.999)=0.065`.

The ratio for each element (divide by smaller mol⇒Arsenic)

Arsenic : Oxygen :

`\tt (0.0435)/(0.0435)/ (0.065)/(0.0435)=1/ 1.5\rightarrow 2/ 3`

The empirical formula : As₂O₃