Balancing Chemical Equations

• What is necessary to show what happens in a chemical reaction?

  Understanding chemical equations
• What is one way to show a chemical reaction?

  Using a word equation
• What do we call the substances that react in a chemical equation?

  Reactants
• What are the substances produced in a chemical reaction called?

  Products
• What does the arrow in a chemical equation represent?

  Reactants react to form products
• What is the symbol for methane in a chemical equation?

  $CH_4$
• What is the symbol for oxygen in a chemical equation?

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


  Oxygen exists as a molecule of two atoms
• What is required for a chemical equation to be balanced?

  Same total number of each atom on both sides
• How many carbon, hydrogen, and oxygen atoms are on the left side of the equation?

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

  1 carbon, 2 hydrogens, 3 oxygens
• What is the first rule of balancing chemical equations?

  Do not change the small numbers
• Why can't we change the small numbers in a chemical equation?

  It changes the type of chemicals involved
• How do we increase the number of oxygen atoms on the left side?

  Put a 2 in front of $O_2$
• What happens if we try to use one and a half molecules of oxygen?

  We must round up to two molecules
• How do we balance the number of hydrogens and oxygens on the right side?

  Increase the number of water molecules
• What is the process for balancing chemical equations?

  1. Identify reactants and products
  2. Count atoms on both sides
  3. Adjust coefficients to balance atoms
  4. Ensure whole numbers are used
  5. Double-check for balance
• What is the chemical equation for sulfuric acid reacting with sodium hydroxide?

  H2SO4 + NaOH → Na2SO4 + H2O
• How many hydrogens, sulfur, oxygens, and sodiums are on the left side of the sulfuric acid equation?

  3 hydrogens, 1 sulfur, 5 oxygens, 1 sodium
• How many hydrogens, sulfur, oxygens, and sodiums are on the right side of the sulfuric acid equation?

  2 hydrogens, 1 sulfur, 5 oxygens, 2 sodiums
• Which elements should be balanced first in the sulfuric acid equation?

  Sulfur and sodium
• What do we do after balancing sodium in the sulfuric acid equation?

  Count atoms again for balance
• How do we fix the common problem of needing more hydrogens and oxygens on the right side?

  Add one more water molecule
• What should you do after you think the equation is balanced?

  Double-check to see if it's balanced
• What is the final balanced equation for sulfuric acid and sodium hydroxide?

  • H2SO4 + 2NaOH → Na2SO4 + 2H2O