Lesson 10

• What does a chemical equation describe?

  A chemical equation describes a chemical change.
• What are the parts of a chemical equation?

  • Reactants: Chemicals before the reaction (left side)
  • Products: New chemicals formed (right side)
  • Reaction symbol: Indicates the type of reaction
• What is a reactant in a chemical equation?

  A reactant is the chemical(s) you start with before the reaction.
• Where are reactants written in a chemical equation?

  Reactants are written on the left side of the equation.
• What is a product in a chemical equation?

  A product is the new chemical(s) formed by the reaction.
• Where are products written in a chemical equation?

  Products are written on the right side of the equation.
• What does a subscript in a chemical formula indicate?

  A subscript shows how many atoms of an element are in a molecule.
• How many atoms of hydrogen and oxygen are in water (H2O)?

  There are 2 atoms of hydrogen and 1 atom of oxygen in water.
• What does a coefficient in a chemical equation indicate?

  A coefficient shows how many molecules there are of a particular chemical.
• How many water molecules are represented by the coefficient in 3 H2O?

  There are 3 water molecules.
• What does the law of conservation of mass state in a chemical reaction?

  In a chemical reaction, matter is neither created nor destroyed.
• What must be true about the number and type of atoms in a balanced chemical reaction?

  The number and type of atoms going into a reaction must be the same as those coming out.
• What does it mean for a chemical equation to obey the law of conservation of mass?

  It means the equation is balanced.
• What are the rules for balancing chemical equations?

  1. Matter cannot be created or destroyed.
  2. Subscripts cannot be added, removed, or changed.
  3. You can only change coefficients.
  4. Coefficients can only go in front of chemical formulas.
• What are some tips for balancing chemical equations?

  • Balance big formulas first; save free elements for last.
  • Treat the same polyatomic ion as one unit if it appears on both sides.
  • Some equations may require creativity to balance.
• How do you balance a chemical equation by adjusting coefficients?

  • Identify the number of atoms for each element in reactants and products.
  • Adjust coefficients to ensure the same number of each type of atom on both sides.
• What is the initial state of the reactants and products in the provided balancing example?

  The initial state is K, Cl, O with coefficients 1, 1, 1 for reactants and 3, 2, 2 for products.
• What are the final coefficients for the products in the provided balancing example?

  The final coefficients for the products are 2, 2, 6.
• What are the final coefficients for the reactants in the provided balancing example?

  The final coefficients for the reactants are 1, 1, 1.
• What is the significance of balancing chemical equations?

  • Ensures the law of conservation of mass is followed.
  • Indicates the correct proportions of reactants and products.
  • Essential for accurate chemical calculations and predictions.