Amount of Substance

• What is the focus of this video?

  Amount of substance for AQA exam
• What is the mole in chemistry?

  A way of measuring the amount of substance
• What is Avogadro's number?

  $6.02 \times 10^{23}$
• How many molecules are in one mole of water?

  $6.02 \times 10^{23}$ molecules
• How do you calculate the number of particles in a substance?

  Multiply Avogadro's number by the number of moles
• What is the formula to calculate the number of particles?

  Number of particles = Avogadro's number × moles
• How many particles are in 0.67 moles of ammonia?

  $4.02 \times 10^{23}$ particles
• What is the formula for calculating the number of moles using mass?

  Number of moles = mass (g) / Molar mass (g/mol)
• How do you calculate the number of moles in 23 g of gold?

  0.12 moles
• What is the atomic mass of gold (Au)?

  197 g/mol
• What is the formula for calculating moles in a solution?

  Number of moles = concentration (mol/dm³) × volume (dm³)
• How do you convert volume from cm³ to dm³?

  Divide by 1000
• What is the number of moles in 200 cm³ of 35 mol/dm³ HCl?

  0.07 moles
• What is the ideal gas equation?

  PV = nRT
• What does R represent in the ideal gas equation?

  The gas constant, 8.31 J/(K·mol)
• How do you convert pressure from kilopascals to pascals?

  Multiply by 1000
• How do you convert temperature from Celsius to Kelvin?

  Add 273
• What is the volume of 0.36 moles of gas at 100 kPa and 298 K?

  8.91 × 10³ cm³
• What is the importance of unit conversion in chemistry?

  Ensures accurate calculations and results
• What is the conversion factor from meters to centimeters?

  100 cm in 1 m
• How do you convert from m² to cm²?

  Multiply by 10,000
• How do you convert from m³ to cm³?

  Multiply by 1,000,000
• What are the key components of the ideal gas equation?

  • P: Pressure in pascals
  • V: Volume in meters cubed
  • n: Number of moles
  • R: Gas constant (8.31 J/(K·mol))
  • T: Temperature in Kelvin
• What are the steps to convert units in chemistry?

  1. Identify the current unit and desired unit.
  2. Use conversion factors to change units.
  3. Apply the conversion to the measurement.
  4. Ensure the final unit is appropriate for the context.
• How do you convert meters to decimeters?

  Multiply by 100
• Why do we multiply by 100 when converting from meters to centimeters?

  There are 100 centimeters in a meter
• What is the conversion factor from meters to centimeters?

  100
• What is the general rule for converting between dimensions?

  Add a zero for each dimension increase
• How do you convert square meters to square decimeters?

  Multiply by 100
• What is the conversion factor from cubic meters to cubic decimeters?

  1000
• How do you convert cubic meters to cubic centimeters?

  Multiply by 1,000,000
• What are ionic equations used for?

  To show ions formed in solution
• What do ionic equations represent in a reaction?

  They show which particles are reacting
• What is the full ionic equation for sulfuric acid reacting with potassium hydroxide?

  2 H⁺ + 2 OH^- → 2 H₂O
• What are spectator ions in an ionic equation?

  They do not participate in the reaction
• What do state symbols represent in chemical equations?

  Physical states of substances
• What does AQ stand for in state symbols?

  Aqueous, meaning dissolved in water
• How do you calculate theoretical mass from a balanced equation?

  Use molar ratios from the equation
• What is the molar mass of calcium (Ca)?

  40 g/mol
• How do you find the mass of calcium oxide produced from 34 g of calcium?

  Calculate using molar ratios