Question

select the correct answer. zoe is investigating the composition of substance a, an unknown substance. using chemical processes, she analyzes substance a and determines it is composed of sodium, oxygen, and hydrogen atoms in a ratio of 1 : 1 : 1. what is substance a?
a. a compound
b. an element
c. a heterogeneous mixture
d. a homogeneous mixture

Explanation:

1. Recall the definitions:

• An element is a pure substance made of only one type of atom. Since substance A has sodium, oxygen, and hydrogen atoms, it's not an element (eliminates B).
• A mixture (homogeneous or heterogeneous) consists of two or more substances physically combined, not chemically. Substance A is analyzed via chemical processes, implying a chemical composition, so it's not a mixture (eliminates C and D).
• A compound is a pure substance made of two or more different elements chemically combined in a fixed ratio. Substance A has sodium, oxygen, and hydrogen in a 1:1:1 ratio (fixed), so it's a compound.

Answer:

A. a compound