Which statement describes evidence of chemical reaction

Write a net ionic equation to show that hydrofluoric acid, behaves as an acid in water.

What element breaks down into yttrium-90?

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