Unit 9: Moles & Stoichiometry

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Regents Core Curriculum


  • In all chemical reactions there is a conservation of mass, energy, and charge. (3.3a) 
  • A balanced chemical equation represents conservation of atoms. The coefficients in a balanced chemical equation can be used to determine mole ratios in the reaction. (3.3c) 
  • Types of chemical reactions include synthesis, decomposition, single replacement, and double replacement. (3.2b)
  • A physical change results in the rearrangement of existing particles in a substance. A chemical change results in the formation of different substances with changed properties. (3.2a) 
  • Chemical and physical changes can be exothermic or endothermic. (4.1b) 
  • The formula mass of a substance is the sum of the atomic masses of its atoms. The molar mass (gram formula mass) of a substance equals one mole of that substance. (3.3e) 
  • The percent composition by mass of each element in a compound can be calculated mathematically. (3.3f) 
    Types of chemical formulas include empirical, molecular, and structural. (3.1ee) 
  • The empirical formula of a compound is the simplest whole-number ratio of atoms of the elements in a compound. It may be different from the molecular formula, which is the actual ratio of atoms in a molecule of that compound. (3.3d) 
  • The concentration of a solution may be expressed as molarity (M), percent by volume, percent by mass, or parts per million (ppm). (3.1pp)
  • The addition of a nonvolatile solute to a solvent causes the boiling point of the solvent to increase and the freezing point of the solvent to decrease. The greater the concentration of particles, the greater the effect. (3.1qq)