C3- Quantitative Chemistry

• What is conserved in a chemical reaction?

  Total mass of all substances
• Why must we balance chemical equations?

  Atoms that go in must come out
• What do we add up to find the relative formula mass of a compound?

  Individual relative atomic masses
• How do you calculate the relative formula mass of CO2?

  12 plus 2 times 16 equals 44
• What happens when a gas product leaves the reaction vessel?

  It results in a decrease in mass
• What is a mole in chemistry?

  A specific number of atoms or molecules
• Why don't foundation students need to deal in moles?

  They focus on basic concepts instead
• How many grams of a substance equal one mole?

  As many grams as its relative atomic mass
• How do you calculate the number of moles from grams?

  Moles equals grams over Rams
• What is the relative atomic mass of carbon?

  12 grams
• How many moles of methane are in 64 grams?

  4 moles of methane
• What does a coefficient of 2 in front of water indicate?

  Double the moles of water produced
• How do you calculate the mass of water produced from moles?

  Mass equals moles times Rams
• What is the relative atomic mass of water?

  18 grams
• What is the mass of water produced from 8 moles?

  144 grams of water
• What units can mass be given in for calculations?

  Grams, kilograms, or tons
• What is a limiting reactant?

  The reactant that runs out first
• How is concentration of solutions often expressed?

  In grams per decimetre cubed
• What does a concentration of 1 mole per decimetre cubed mean?

  One mole of HCl in one decimetre cubed
• What is percentage yield?

  Actual product made compared to theoretical
• How do you calculate percentage yield?

  Actual mass divided by theoretical mass
• What does atom economy measure?

  Efficiency of mass in a reaction
• How do you calculate atom economy?

  Ram of desired product over total Ram of reactants
• What is the relative atomic mass of CO2?

  44 grams
• What is the volume occupied by one mole of any gas at RTP?

  24 decimetres cubed
• How do you convert moles to volume?

  Multiply or divide by 24
• What is the process of balancing chemical equations?

  • Ensure the same number of each atom on both sides
  • Adjust coefficients to achieve balance
  • Use relative atomic masses for calculations
• What are the key concepts of stoichiometry in reactions?

  • Moles represent quantities of substances
  • Ratios of reactants and products
  • Limiting reactants determine yield
• What are the implications of conservation of mass in reactions?

  • Mass of reactants equals mass of products
  • No atoms are lost or gained
  • Important for calculating yields and efficiencies
• What are the factors affecting percentage yield?

  • Incomplete reactions
  • Side reactions producing by-products
  • Loss of product during recovery
• What is the significance of atom economy in chemical processes?

  • Measures efficiency of resource use
  • Higher atom economy means less waste
  • Important for sustainable chemistry practices