A scientist is studying a shock wave from an earthquake. What kind of wave is being studying?

an electromagnetic wave
a gamma ray
a radio wave
a mechanical wave.

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

Table sugar completely dissolved in water is an example of a?

How do you know when a chemical reaction has occurred