quantitative chemistry

• What is relative formula mass (Mr)?

  Sum of relative atomic masses in a formula
• How do you calculate the percentage mass of an element in a compound?

  Ar x number of atoms / Mr x 100
• What does Ar stand for in chemistry?

  Relative atomic mass
• What is the definition of 'the mole' in chemistry?

  An amount of a substance
• What is the numerical value of one mole of particles?

  6.02 × 10²³
• How does the mass of one mole of a substance relate to its relative formula mass?

  It equals the relative formula mass in grams
• What is the unit for measuring moles?

  mol
• How do you calculate the number of moles in a substance?

  Mass in g / Mr of the substance
• What does the number in front of an element indicate?

  How many moles of that element
• What is concentration in a solution?

  Amount of substance in a certain volume
• How does the amount of solute affect concentration?

  More solute increases the concentration
• What is the formula for concentration?

  Mass of solute / volume of solvent
• When does a chemical reaction stop?

  When one reactant is completely used up
• What is a limiting reactant?

  The reactant that is used up first
• How is the amount of product formed related to the limiting reactant?

  It is directly proportional to its amount
• What are the key concepts related to relative formula mass and moles?

  • Relative formula mass (Mr) is the sum of atomic masses.
  • Percentage mass of an element = (Ar x number of atoms) / (Mr x 100).
  • One mole = 6.02 × 10²³ particles.
  • Mass of one mole in grams equals Mr.
  • Concentration = mass of solute / volume of solvent.
  • Limiting reactant stops the reaction when used up.
• What does the term mole refer to in chemistry?

  A unit to measure the amount of substance
• How is the mole similar to other units like meters and seconds?

  It measures the amount of substance
• How many particles are in one mole of a substance?

  $6.02 \times 10^{23}$ particles
• What does the term "particles" refer to in the context of moles?

  Atoms, molecules, ions, or electrons
• If you have one mole of carbon, how many atoms are present?

  $6.02 \times 10^{23}$ atoms of carbon
• What is Avogadro's constant?

  The number of particles in one mole
• Why is Avogadro's constant significant in chemistry?

  It relates mass to relative atomic or formula mass
• What is the relative atomic mass of carbon?

  12
• What is the relative formula mass of oxygen in O₂?

  32
• How much does one mole of CO₂ weigh?

  44 grams
• What formula relates the number of moles to mass and relative formula mass?

  Number of moles = mass / relative formula mass
• How many moles are in 42.5 grams of ammonia?

  2.5 moles
• What is the molar mass of ammonia (NH₃)?

  17
• How do you calculate the mass of 3 moles of CO₂?

  132 grams
• How much carbon is in 3 moles of CO₂?

  36 grams
• What is the mass of oxygen in 3 moles of CO₂?

  96 grams
• How can chemical equations be interpreted in terms of moles?

  As ratios of reactants and products
• If you start with 2 moles of magnesium, how many moles of hydrochloric acid are needed?

  4 moles
• How does the mole concept help in understanding chemical reactions?

  It provides a way to quantify reactants and products
• What is produced when 1 mole of magnesium reacts with hydrochloric acid?

  1 mole of magnesium chloride
• What is the relative formula mass of CO₂?

  44
• mols = vol x concentration
• cm -> dm = divide by 1000
• moles = mass divided by mr