C3-quantitative chemistry

• What is relative formula mass?

  It is the sum of the relative atomic masses of all the atoms in a molecular formula.
• How do you calculate the percentage mass of an element in a compound?


  • Use the formula:

  \[

  \text{Percentage mass of an element} = \frac{A \times \text{number of atoms of that element}}{M} \times 100

  \]
• What is a mole in chemistry?

  A mole is the amount of a substance that contains Avogadro's number of particles, which is \(6.02 \times 10^{23}\).
• What is the Avogadro constant?

  It is \(6.02 \times 10^{23}\).
• How does the mass of one mole of a substance relate to its relative atomic mass?

  The mass of one mole of a substance in grams is equal to its relative atomic mass (A) or relative formula mass (M).
• How do you calculate the number of moles from a given mass?

  Use the formula:

  \[

  \text{Number of moles} = \frac{\text{mass in g}}{M}

  \]
• How do you show that mass is conserved in a chemical reaction?

  Add up the relative formula masses of the reactants and products to confirm they are equal.
• What happens to mass during a chemical reaction?

  Mass is always conserved; no atoms are destroyed or created.
• What is the significance of the limiting reactant in a chemical reaction?

  The limiting reactant determines the maximum amount of product that can be formed.
• How can you calculate the mass of a product formed in a reaction?

  Use the mass of the limiting reactant and the balanced reaction equation.
• What is concentration in chemistry?


  • Concentration is the amount of a substance in a given volume of solution.
  • More solute in a given volume means a more concentrated solution.
• How do you calculate the concentration of a solution in g/dm³?


  Use the formula:

  \[

  \text{Concentration} = \frac{\text{mass of solute}}{\text{volume of solvent in dm}^3}

  \]
• How do you convert volume from cm³ to dm³?

  Divide the volume in cm³ by 1000.