Which is true of any physical or chemical change? A. Mass and energy are conserved.
B. Mass and energy increase.
C. Mass and energy decrease.
D. Mass and energy are reversed.

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

Which of the following is true about the speed of light? it depends on the wavelength.

Chromium(iii) sulfate is a transition metal compound containing the metal chromium and the polyatomic ion sulfate. the oxidation state of chromium in this compound is , and the chemical formula of the compound is ( ) . reset next