Question

A given sample of pure compound contains $9.81\text{g}$ of $Zn$, $1.8\times {10}^{23}$ atoms of chromium and 0.60 mol of oxygen atoms. What is the simplest formula?

• A. $ZnC{r}_2{O}_7$
• B. $ZnC{r}_2{O}_4$
• C. $ZnCr{O}_4$
• D. $ZnC{r}_2{O}_6$

Answer 1

The correct option is B $ZnC{r}_2{O}_4$

Moles of $Zn=0.15$
Moles of $Cr=0.3$
Moles of $O=0.6$
Mole ratio of $Zn:Cr:O=0.15:0.3:0.6=1:2:4$
The formula is $ZnC{r}_2{O}_4$