Balancing Equations

• What is needed to show what's happening in a chemical reaction?

  Chemical equations
• What is the purpose of a word equation in chemistry?

  To show reactants and products
• What are the molecules on the left side of a chemical equation called?

  Reactants
• Why is oxygen written as O2 in chemical equations?

  Oxygen exists as a molecule of two atoms
• What are the molecules on the right side of a chemical equation called?

  Products
• What is the symbol for methane in chemical equations?

  CH4
• Why do chemical equations need to be balanced?

  To have the same number of each type of atom on both sides
• What is the first rule of balancing chemical equations?

  Can't change the little numbers
• Why can't we change the little numbers in a chemical equation?

  It would change the type of chemicals
• What is the second rule of balancing chemical equations?

  Must keep whole numbers
• How would you balance the equation CH4 + O2 -> CO2 + H2O?

  CH4 + 2O2 -> CO2 + 2H2O
• Why is it recommended to balance the least common elements first in a chemical equation?

  To simplify the balancing process
• How would you balance the equation H2SO4 + NaOH -> Na2SO4 + H2O?

  H2SO4 + 2NaOH -> Na2SO4 + 2H2O
• What are the steps to balance a chemical equation?

  1. Identify the reactants and products
  2. Count the number of atoms of each element on both sides
  3. Change the big numbers in front of the elements or compounds to balance the equation
  4. Keep whole numbers and don't change the little numbers
  5. Check the equation to make sure it is balanced
• What is a chemical equation?

  A representation of a chemical reaction
• What is the difference between a word equation and a symbol equation?

  A word equation uses words, a symbol equation uses symbols
• Why is it important to balance chemical equations?

  To ensure the law of conservation of mass is obeyed
• What are the rules for balancing chemical equations?

  1. Can't change the little numbers
  2. Must keep whole numbers
  3. Change the big numbers in front of the elements or compounds to balance the equation
• What is the process of balancing a chemical equation?

  Count the number of atoms, change the big numbers, keep whole numbers