2H2(g) +0,(9) 0 24,0(g)
What kind of change is shown?

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

Use examples from the article to explain one positive and one negative effect that chemistry has had on society.

How could a student test the effect of removing heat from a gas that is stored in a sealed container? what must occur in order for matter to change states?