Question

which pure substance can be classified as an element?
$ce{h_{2}}$
$ce{no_{3}}$
$ce{nacl}$
$ce{h_{2}so_{4}}$

Explanation:

atoms, so it is an element.

• $\text{NO}_3$: Contains nitrogen + oxygen, compound.
• $\text{NaCl}$: Contains sodium + chlorine, compound.
• $\text{H}_2\text{SO}_4$: Contains hydrogen + sulfur + oxygen, compound.

Answer:

atoms, so it is an element.

• $\text{NO}_3$: Contains nitrogen + oxygen, compound.
• $\text{NaCl}$: Contains sodium + chlorine, compound.
• $\text{H}_2\text{SO}_4$: Contains hydrogen + sulfur + oxygen, compound.