Which of the following is best described by the term macroscopic? A. Water in the liquid phase boils to become a gas.
B. Water molecules in the solid phase are tightly held together.
C. H2O
D. Water is composed of two hydrogen atoms and one oxygen atom.

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

Aglow stick contains a glass vial with chemicals. when the glow stick is bent, the vial breaks and the chemicals react to produce a glow. a science student observes that a glow stick kept in the freezer glows for a longer duration than a glow stick kept at room temperature. what conclusion can be drawn based on the observation? be sure to note the outcome and test variables in the conclusion.

How is the atomic number of a nucleus changed by alpha decay