Mole calculations

• What is the mole in chemistry?

  The unit for the amount of substance
• How can the number of particles in a substance be found?

  Using the Avogadro constant
• What does the mass of a product depend on?

  The mass of the limiting reactant
• What is the definition of a mole?

  • Contains the same number of particles as 12 g of carbon-12
  • Equal to Avogadro's constant, \(6.02 \times 10^{23}\)
• What is the relative atomic mass (A_r)?

  The mean relative mass of isotopes in an element
• How is the relative formula mass (M_r) calculated?

  Sum of the relative atomic masses in a formula
• What is the formula for calcium?

  Ca
• What is the RFM of oxygen (O₂)?

  32
• What is the Avogadro constant?

  Number of particles in one mole, \(6.02 \times 10^{23}\)
• How is one mole defined?

  As the Avogadro constant number of particles
• How many molecules are in 1 mole of methane (CH₄)?

  6.02 × 10²³
• How many atoms are in 1 mole of water (H₂O)?

  3 × 6.02 × 10²³
• How do you calculate the number of water molecules in 0.5 mol of water?

  Number of molecules = \(6.02 \times 10^{23} \times 0.5\)
• How many oxygen atoms are in 0.5 mol of O₂? Show the calculation.

  Number of atoms = \(2 \times 0.5 \times 6.02 \times 10^{23}\)
• What are the key concepts related to moles and masses in chemistry?

  • Mole as a unit of measurement
  • Avogadro constant: \(6.02 \times 10^{23}\)
  • Relative atomic mass (A_r) and relative formula mass (M_r)
  • Calculating number of particles from moles
• What is a molecule in chemistry?

  A collection of two or more atoms
• What is an atom?

  The smallest part of an element
• What is a limiting reactant?

  The reactant that is completely consumed first
• How does mass relate to moles in a chemical reaction?

  Mass is proportional to the number of moles
• Why are chemical formulas important in calculations?

  They indicate the composition of substances
• Why is it important to understand particle types in calculations?

  Different particles affect calculations differently
• What is the unit for the amount of substance?

  The mole
• How can the number of particles in a substance be found?

  Using the Avogadro constant
• What does the mass of a product depend on?

  The mass of the limiting reactant
• What is the definition of mass in chemistry?

  • Amount of matter in an object
  • Measured in kilograms (kg) or grams (g)
• How can the mass of a substance be calculated?

  From the number of moles
• What is the definition of a mole?

  Contains the same number of particles as 12 g of carbon-12
• What is relative formula mass (M_r)?

  The sum of the relative atomic masses in a formula
• What is relative atomic mass (A_r)?

  The mean relative mass of an element's isotopes
• What is an atom?

  The smallest part of an element that can exist
• What is a metal?

  A shiny element that conducts electricity
• How is the mass of a given number of moles calculated?

  • Formula: \(mass~in~g = M_{r} \times number~of~moles\)
  • Remember: 'mass equals mister mole'
• What is the mass of 0.25 mol of carbon dioxide (M_r = 44)?

  11 g
• How do you calculate the mass of 0.10 mol of iron (A_r = 56)?

  mass = 5.6 g
• How is the amount of a given mass of substance calculated?

  • Formula: \(amount~in~mol = \frac{mass~in~g}{M_{r}}\)
  • Use A_r for metals or separate atoms
• What is the amount of carbon atoms in 6.0 g of carbon (A_r = 12)?

  0.5 mol
• What are the key concepts related to moles and masses in chemistry?

  • Mole as a unit of substance
  • Avogadro constant for particles
  • Mass calculated from moles
  • M_r and A_r definitions
• What is the mole in chemistry?

  The unit for the amount of substance
• How can the number of particles in a substance be found?

  Using the Avogadro constant
• What does the mass of the product depend on?

  The mass of the limiting reactant