Quantitative chemistry

• What are the subtopics covered in the video?

  • Relative formula mass
  • The mole
  • Concentration
  • Limiting reactants
  • Balancing equations
• What is relative formula mass?

  Sum of atomic masses in a molecular formula
• How do you calculate the relative formula mass of $MgCl_2$?


  Add atomic mass of magnesium and chlorine
• What is the atomic mass of magnesium?

  24
• What is the atomic mass of chlorine?

  35.5
• What is the total relative formula mass of $MgCl_2$?


  95
• What is a mole defined as?

  Amount of substance containing $6.02 \times 10^{23}$ particles
• What is Avogadro's constant?

  $6.02 \times 10^{23}$
• How does a mole relate to atomic mass?

  One mole of an element weighs its atomic mass in grams
• What is the mole equation?

  Number of moles = mass in grams / relative atomic mass
• What does the triangle for the mole equation represent?

  Mass on top, moles and relative mass below
• What is a key fact about mass in chemical reactions?

  Mass is always conserved in a reaction
• What is the concentration equation?

  Concentration = mass / volume
• What are the units for concentration?

  g/dm³
• What does concentration represent in a solution?

  Amount of substance in a volume of solution
• How would you describe a high concentration of coffee?

  Little milk compared to coffee
• What is a limiting reactant?

  Reactant that runs out first in a reaction
• How does the limiting reactant affect product yield?

  It determines the amount of product produced
• What is the process for balancing chemical equations?

  1. Write the unbalanced equation.
  2. List the number of each atom on both sides.
  3. Adjust coefficients to balance atoms.
  4. Ensure all atoms match on both sides.
• How do you balance the equation $NaO_3 \rightarrow NaCl +$$O_2$?


  Adjust coefficients to equalize atoms
• What is the first step in balancing the equation?

  Count the number of each atom on both sides
• Why do you need to find a common multiple when balancing oxygen atoms?

  To make the number of oxygen atoms equal
• What do you do after adjusting the oxygen atoms in balancing?

  Adjust other coefficients to match
• What is the final step in balancing equations?

  Ensure all atoms are equal on both sides