What is the percent by mass of water in the hydrate CoCl₂ · 6H₂O?

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

What are the first three quantum numbers for the electrons located in subshell 2s?

Chromosome 17 is made of over million base pairs.