Move these inside rather than at the beginning

HS-PS1-1. Use the periodic table as a model to predict the relative properties of main group
elements, including ionization energy and relative sizes of atoms and ions, based on
the patterns of electrons in the outermost energy level of each element. Use the
patterns of valence electron configurations, core charge, and Coulomb’s law to
explain and predict general trends in ionization energies, relative sizes of atoms and
ions, and reactivity of pure elements.
Clarification Statement:
• Size of ions should be relevant only for predicting strength of ionic bonding.
State Assessment Boundary:
• State assessment will be limited to main group (s and p block) elements.

HS-PS1-2. Use the periodic table model to predict and design simple reactions that result in two
main classes of binary compounds, ionic and molecular. Develop an explanation
based on given observational data and the electronegativity model about the relative
strengths of ionic or covalent bonds.
Clarification Statements:
• Simple reactions include synthesis (combination), decomposition, single
displacement, double displacement, and combustion.
• Predictions of reactants and products can be represented using Lewis dot
structures, chemical formulas, or physical models.
• Observational data include that binary ionic substances (i.e., substances that have
ionic bonds), when pure, are crystalline salts at room temperature (common
examples include NaCl, KI, Fe2O3); and substances that are liquids and gases at
room temperature are usually made of molecules that have covalent bonds
(common examples include CO2, N2, CH4, H2O, C8H18).

HS-PS1-3. Cite evidence to relate physical properties of substances at the bulk scale to spatial
arrangements, movement, and strength of electrostatic forces among ions, small
molecules, or regions of large molecules in the substances. Make arguments to
account for how compositional and structural differences in molecules result in
different types of intermolecular or intramolecular interactions.
Clarification Statements:
• Substances include both pure substances in solid, liquid, gas, and networked
forms (such as graphite).
• Examples of bulk properties of substances to compare include melting point and
boiling point, density, and vapor pressure.
• Types of intermolecular interactions include dipole-dipole (including hydrogen
bonding), ion-dipole, and dispersion forces.
State Assessment Boundary:
• Calculations of vapor pressure by Raoult’s law, properties of heterogeneous
mixtures, and names and bonding angles in molecular geometries are not
expected in state assessment.

HS-PS1-4. Develop a model to illustrate the energy transferred during an exothermic or
endothermic chemical reaction based on the bond energy difference between bonds
broken (absorption of energy) and bonds formed (release of energy).
Clarification Statement:
• Examples of models may include molecular-level drawings and diagrams of
reactions or graphs showing the relative energies of reactants and products.
State Assessment Boundary:
• Calculations using Hess’s law are not expected in state assessment.
82 2016 Massachusetts Science and Technology/Engineering Curriculum Framework
HS-PS1-5. Construct an explanation based on kinetic molecular theory for why varying
conditions influence the rate of a chemical reaction or a dissolving process. Design
and test ways to slow down or accelerate rates of processes (chemical reactions or
dissolving) by altering various conditions.*
Clarification Statements:
• Explanations should be based on three variables in collision theory: (a) quantity
of collisions per unit time, (b) molecular orientation on collision, and (c) energy
input needed to induce atomic rearrangements.
• Conditions that affect these three variables include temperature, pressure,
concentrations of reactants, agitation, particle size, surface area, and addition of a
catalyst.
State Assessment Boundary:
• State assessment will be limited to simple reactions in which there are only two
reactants and to specifying the change in only one variable at a time.

HS-PS1-6. Design ways to control the extent of a reaction at equilibrium (relative amount of
products to reactants) by altering various conditions using Le Chatelier’s principle.
Make arguments based on kinetic molecular theory to account for how altering
conditions would affect the forward and reverse rates of the reaction until a new
equilibrium is established.*
Clarification Statements:
• Conditions that can be altered to affect the extent of a reaction include
temperature, pressure, and concentrations of reactants.
• Conditions that can be altered to affect the rates of a reaction include
temperature, pressure, concentrations of reactants, agitation, particle size, surface
area, and addition of a catalyst.
State Assessment Boundaries:
• Calculations of equilibrium constants or concentrations are not expected in state
assessment.
• State assessment will be limited to simple reactions in which there are only two
reactants and to specifying the change in only one variable at a time.

HS-PS1-7. Use mathematical representations and provide experimental evidence to support the
claim that atoms, and therefore mass, are conserved during a chemical reaction. Use
the mole concept and proportional relationships to evaluate the quantities (masses or
moles) of specific reactants needed in order to obtain a specific amount of product.
Clarification Statements:
• Mathematical representations include balanced chemical equations that represent
the laws of conservation of mass and constant composition (definite proportions),
mass-to-mass stoichiometry, and calculations of percent yield.
• Evaluations may involve mass-to-mass stoichiometry and atom economy
comparisons, but only for single-step reactions that do not involve complexes.

HS-PS1-9(MA). Relate the strength of an aqueous acidic or basic solution to the extent of an acid
or base reacting with water as measured by the hydronium ion concentration (pH) of
the solution. Make arguments about the relative strengths of two acids or bases with
similar structure and composition.
Clarification Statements:
• Reactions are limited to Arrhenius and Bronsted-Lowry acid-base reaction
patterns with monoprotic acids.
• Comparisons of relative strengths of aqueous acid or base solutions made from
similar acid or base substances is limited to arguments based on periodic
properties of elements, the electronegativity model of electron distribution,
empirical dipole moments, and molecular geometry. Acid or base strength
2016 Massachusetts Science and Technology/Engineering Curriculum Framework 83
comparisons are limited to homologous series and should include dilution and
evaporation of water.

HS-PS1-10(MA). Use an oxidation-reduction reaction model to predict products of reactions
given the reactants, and to communicate the reaction models using a representation
that shows electron transfer (redox). Use oxidation numbers to account for how
electrons are redistributed in redox processes used in devices that generate electricity
or systems that prevent corrosion.*
Clarification Statement:
• Reactions are limited to simple oxidation-reduction reactions that do not require
hydronium or hydroxide ions to balance half-reactions.

HS-PS1-11(MA). Design strategies to identify and separate the components of a mixture based on
relevant chemical and physical properties.
Clarification Statements:
• Emphasis is on compositional and structural features of components of the
mixture.
• Strategies can include chromatography, distillation, centrifuging, and
precipitation reactions.
• Relevant chemical and physical properties can include melting point, boiling
point, conductivity, and density.
[HS-PS1-8 is found in introductory physics.]
PS2. Motion and Stability: Forces and Interactions

HS-PS2-6. Communicate scientific and technical information about the molecular-level structures
of polymers, ionic compounds, acids and bases, and metals to justify why these are
useful in the functioning of designed materials.*
Clarification Statement:
• Examples could include comparing molecules with simple molecular geometries;
analyzing how pharmaceuticals are designed to interact with specific receptors;
and considering why electrically conductive materials are often made of metal,
household cleaning products often contain ionic compounds to make materials
soluble in water, or materials that need to be flexible but durable are made up of
polymers.
State Assessment Boundary:
• State assessment will be limited to comparing substances of the same type with
one compositional or structural feature different.

HS-PS2-7(MA). Construct a model to explain how ions dissolve in polar solvents (particularly
water). Analyze and compare solubility and conductivity data to determine the extent
to which different ionic species dissolve.
Clarification Statement:
• Data for comparison should include different concentrations of solutions with the
same ionic species, and similar ionic species dissolved in the same amount of
water.

HS-PS2-8(MA). Use kinetic molecular theory to compare the strengths of electrostatic forces and
the prevalence of interactions that occur between molecules in solids, liquids, and
gases. Use the combined gas law to determine changes in pressure, volume, and
temperature in gases.

PS3. Energy
HS-PS3-4b. Provide evidence from informational text or available data to illustrate that the
transfer of energy during a chemical reaction in a closed system involves changes in
energy dispersal (enthalpy change) and heat content (entropy change) while assuming
the overall energy in the system is conserved.
State Assessment Boundary:
• Calculations involving Gibbs free energy are not expected in state assessment.

Curriculum Map - BHS - Science - CHEMISTRY

UNIT Stoichiometry

UNIT:  Solutions

UNIT:  Periodic Table and Periodicity

UNIT: Acids and Bases