Clarification Statement - S.MS.PS.1.5.CS:
Emphasis is on law of conservation of matter and on physical models or drawings, including digital forms, that represent atoms.

Assessment Boundary - S.MS.PS.1.5.AB:
Assessment does not include the use of atomic masses, balancing symbolic equations, or intermolecular forces.

Science and Engineering Practices - 6-8.SEP2.2:
Develop a model to describe unobservable mechanisms.

Disciplinary Core Ideas - S.MS.PS.1.5.DCI:
PS1.B: Chemical Reactions •(NYSED) Substances react chemically in characteristic ways. In a chemical process, the atoms that make up the original substances are regrouped into different particles and these new substances have different properties from those of the reactants. (Note: This Disciplinary Core Idea is also addressed by MS-PS1-3.) •The total number of each type of atom is conserved, and thus the mass does not change.

Crosscutting Concepts - CC5.6:
Matter is conserved because atoms are conserved in physical and chemical processes.