Using Moles to Balance Equations

• What is the purpose of using moles in balancing chemical equations?

  To balance chemical equations by calculating the number of moles of reactants and products.
• What is the method to calculate the number of moles?

  • Number of moles = mass / relative formula mass
• What is the relative formula mass of hydrogen?

  2
• What is the relative formula mass of chlorine?

  71
• What is the relative formula mass of hydrogen chloride?

  36.5
• How do you determine the number of moles of hydrogen chloride from its mass?

  By dividing the mass of hydrogen chloride by its relative formula mass.
• What is the process to ensure the numbers in a balanced equation are in the lowest possible ratio?

  • Divide all numbers by the smallest number among them.
• Why do we not write the number one in chemical equations?

  Because it is convention to omit the coefficient of one in chemical equations.
• What is the first step in balancing a chemical equation using moles?

  • Calculate the number of moles of all reactants and products.
• What is the relative formula mass of aluminium oxide?

  102
• What is the relative formula mass of iron(II) oxide?

  216
• How do you find the ratio of moles in a chemical reaction?

  By dividing each mole value by the smallest mole value.
• What should you do after calculating the moles of all chemicals in a reaction?

  • Determine the ratio of the moles by dividing by the smallest number.
• What is the relative formula mass of barium chloride?

  684
• What is the relative formula mass of aluminium sulfate?

  1,248
• What is the final step after determining the ratios of moles in a chemical equation?

  • Use the ratios to balance the chemical equation.
• Why is it important to balance chemical equations?

  To ensure the conservation of mass and that the number of atoms is equal on both sides.