Balancing Equations

• What is the purpose of chemical equations in a chemical reaction?

  To show what happens during the reaction
• What is an example of a word equation for a chemical reaction?

  Methane burns in oxygen to form carbon dioxide and water
• What are the reactants in the example of methane burning?

  Methane and oxygen
• What are the products in the example of methane burning?

  Carbon dioxide and water
• What symbol is used to indicate that reactants react to form products in a chemical equation?

  A single arrow
• What is the difference between word equations and symbol equations?

  Symbol equations use chemical symbols instead of words
• What is the chemical symbol for methane?

  $CH_4$
• What is the chemical symbol for oxygen?

  $O_2$
• Why do we write $O_2$ instead of $O$ in chemical equations?


  Because oxygen exists as a molecule made up of two atoms
• What is the first step in balancing a chemical equation?

  Ensure the same total number of each type of atom on both sides
• How many carbon, hydrogen, and oxygen atoms are on the left side of the methane combustion equation?

  1 carbon, 4 hydrogens, and 2 oxygens
• How many carbon, hydrogen, and oxygen atoms are on the right side of the methane combustion equation?

  1 carbon, 2 hydrogens, and 3 oxygens
• What is the rule regarding changing the small numbers in chemical equations?

  You cannot change the small numbers as it alters the type of chemical
• What do the big numbers in front of elements or compounds represent?

  They represent how many of that substance there are
• How do you increase the number of oxygen atoms on the left side of the equation?

  By putting a 2 in front of $O_2$
• Why can't you use one and a half molecules of oxygen when balancing equations?

  Because we need to keep whole numbers
• How do you balance the number of hydrogens on the right side of the methane combustion equation?

  By increasing the number of water molecules from 1 to 2
• What is the process for balancing a chemical equation?

  1. Count the number of each type of atom on both sides.
  2. Adjust the big numbers in front of compounds to balance the atoms.
  3. Ensure whole numbers are used.
  4. Double-check to confirm the equation is balanced.
• In the example of sulfuric acid and sodium hydroxide, how many hydrogens, sulfurs, oxygens, and sodiums are on the right side?

  2 hydrogens, 1 sulfur, 5 oxygens, and 2 sodiums
• In the example of sulfuric acid and sodium hydroxide, how many hydrogens, sulfurs, oxygens, and sodiums are on the left side?

  3 hydrogens, 1 sulfur, 5 oxygens, and 1 sodium
• How do you balance the sodium atoms in the sulfuric acid and sodium hydroxide reaction?

  By putting a 2 in front of sodium hydroxide
• How do you fix the hydrogen and oxygen imbalance after adjusting sodium in the sulfuric acid reaction?

  By adding one more water molecule to the right
• What should you do after balancing a chemical equation?

  Double-check to see if it's balanced
• What is the final balanced equation for the combustion of methane?

  $CH_4 +$$2O_2 \rightarrow CO_2 +$$2H_2O$
• What is the final balanced equation for the reaction of sulfuric acid and sodium hydroxide?

  $H_2SO_4 +$$2NaOH \rightarrow Na_2SO_4 +$$2H_2O$