Question

the molecular formula is $\ce{c6h12o6}$ because one molecule actually contains 6 c, 12 h, and 6 o atoms. for the following compounds determine the number of atoms of each element:

formula	numbers of atoms
$\ce{co2}$	$\ce{c}=1$; $\ce{o}=2$
$\ce{h2o}$	$\ce{h}=2$; $\ce{o}=1$
$\ce{baso4}$	$\ce{ba}=1$; $\ce{s}=1$; $\ce{o}=4$
$\ce{k2o}$	$\ce{k}=2$; $\ce{o}=1$
$\ce{naf}$	$\ce{na}=1$; $\ce{f}=1$
$\ce{naf}$	$\ce{na}=1$; $\ce{f}=1$
$\ce{na2co3}$	$\ce{na}=2$; $\ce{c}=1$; $\ce{o}=3$

Explanation:

Step1: Identify atoms in $\text{CO}_2$

Carbon (C): subscript 1 (implied), Oxygen (O): subscript 2

Step2: Identify atoms in $\text{H}_2\text{O}$

Hydrogen (H): subscript 2, Oxygen (O): subscript 1 (implied)

Step3: Identify atoms in $\text{BaSO}_4$

Barium (Ba): subscript 1 (implied), Sulfur (S): subscript 1 (implied), Oxygen (O): subscript 4

Step4: Identify atoms in $\text{K}_2\text{O}$

Potassium (K): subscript 2, Oxygen (O): subscript 1 (implied)

Step5: Identify atoms in $\text{NaF}$

Sodium (Na): subscript 1 (implied), Fluorine (F): subscript 1 (implied)

Step6: Identify atoms in $\text{Na}_2\text{CO}_3$

Sodium (Na): subscript 2, Carbon (C): subscript 1 (implied), Oxygen (O): subscript 3

Answer:

Formula	Numbers of atoms
$\text{CO}_2$	$\text{C}=1; \text{O}=2$
$\text{H}_2\text{O}$	$\text{H}=2; \text{O}=1$
$\text{BaSO}_4$	$\text{Ba}=1; \text{S}=1; \text{O}=4$
$\text{K}_2\text{O}$	$\text{K}=2; \text{O}=1$
$\text{NaF}$	$\text{Na}=1; \text{F}=1$
$\text{NaF}$	$\text{Na}=1; \text{F}=1$
$\text{Na}_2\text{CO}_3$	$\text{Na}=2; \text{C}=1; \text{O}=3$