Question

3sio₂
silicon dioxide - glass and sand
element si o
how many atoms
3h₂so₄
sulfuric acid - found in car batteries
element h s o
how many atoms
fe₂o₃
iron oxide - rust
element fe o
how many atoms

Explanation:

Step1: Analyze $3SiO_2$

In one $SiO_2$ molecule, there is 1 Si atom and 2 O atoms, so in 1 $SiO_2$ molecule there are 3 atoms. With a coefficient of 3, the number of Si atoms is $3\times1 = 3$, and the number of O atoms is $3\times2=6$.

Step2: Analyze $3H_2SO_4$

In one $H_2SO_4$ molecule, there are 2 H atoms, 1 S atom and 4 O atoms, so 7 atoms in total. With a coefficient of 3, the number of H atoms is $3\times2 = 6$, the number of S atoms is $3\times1=3$, and the number of O atoms is $3\times4 = 12$.

Step3: Analyze $Fe_2O_3$

In $Fe_2O_3$, there are 2 Fe atoms and 3 O atoms.

Answer:

For $3SiO_2$: Si: 3, O: 6
For $3H_2SO_4$: H: 6, S: 3, O: 12
For $Fe_2O_3$: Fe: 2, O: 3