MS-PS1-5 - Develop and use a model to describe how the total number of atoms does not change in a chemical reaction and thus mass is conserved.

Clarification Statement - Emphasis is on law of conservation of matter and on physical models or drawings, including digital forms, that represent atoms.

Assessment Boundary - Assessment does not include the use of atomic masses, balancing symbolic equations, or intermolecular forces.

8.MS-PS1-5 - Use a model to explain that atoms are rearranged during a chemical reaction to form new substances with new properties. Explain that the atoms present in the reactants are all present in the products and thus the total number of atoms is conserved.

Clarification Statement - Examples of models can include physical models or drawings, including digital forms, that represent atoms.

Assessment Boundary - Use of atomic masses, molecular weights, balancing symbolic equations, or intermolecular forces is not expected in state assessment.