Amount of substance (chem0

    Cards (82)

    • What are the two types of formulae mentioned in the study material?
      Empirical and molecular formula
    • What does the empirical formula represent?
      The simplest whole-number ratio of atoms
    • What is the molecular formula of water?
      H₂O
    • Why is the empirical formula important for non-molecular substances?
      It represents the ratio of atoms in giant structures
    • What is relative molecular mass compared to?
      The mass of an atom of carbon-12
    • How do you calculate relative molecular mass?
      Add relative atomic masses of elements
    • What is the molar mass of carbon, C?
      12.0 g mol⁻¹
    • What does the equation n* = *m / *M* represent?
      The relationship between amount, mass, and molar mass
    • If you have 96.0 g of carbon, how many moles do you have?
      8.0 mol
    • How do you calculate the mass of 0.050 mol of NO₂?
      Multiply moles by molar mass
    • What is the molar mass of Na₂CO₃?
      106.0 g mol⁻¹
    • What is the Avogadro constant?
      6.02 × 10²³ mol⁻¹
    • How is the mass of one mole of an element related to its relative atomic mass?
      It equals the relative atomic mass in grams
    • How do you convert cm³ to dm³?
      Divide by 1000
    • What is a standard solution?
      A solution of known concentration
    • How do you calculate the amount of Na₂CO₃ needed for a standard solution?
      Use n* = *c × *V* / 1000
    • What are the steps to calculate the mass required for a standard solution?
      1. Calculate moles needed: n* = *c × *V* / 1000
      2. Determine molar mass of solute
      3. Calculate mass: m* = *n × *M*
    • What is the relationship between moles, concentration, and volume in solutions?
      • Amount of substance *n* (mol)
      • Concentration *c* (mol dm⁻³)
      • Volume *V* (dm³)
      • Formula: n* = *c × *V*
    • What are the common volume measurements used in chemistry?
      • cm³ (millilitres)
      • dm³ (litres)
      • 1 dm³ = 1000 cm³
    • How does the mole relate to counting particles?
      • 1 mole = 6.02 × 10²³ particles
      • Avogadro constant: *N* = 6.02 × 10²³ mol⁻¹
    • What is the significance of the mass of 1 mole of carbon-12?
      • 12 g of carbon-12 contains 6.02 × 10²³ atoms
      • Links atomic mass to macroscopic measurements
    • What is the importance of using the correct formula when working with moles?
      • Ensures clarity in calculations
      • Avoids confusion between different substances
    • What is the concentration of the NaCl solution mentioned?
      0.160 mol dm⁻³
    • How do you calculate the volume of a solution?
      Use the formula V* = *n × 1000 / *c*
    • What is the volume of the solution containing 3.25 × 10⁻³ mol of NaCl?
      20.3 cm³
    • What is a standard solution?
      • A solution of known concentration
      • Often labeled as 1 mol dm⁻³
    • How is a standard solution prepared?
      By dissolving an exact mass of solute
    • How do you calculate the mass required for a standard solution?
      Use the mole concept to find mass
    • How many moles of Na₂CO₃ are needed for 100 cm³ of a 0.250 mol dm⁻³ solution?
      0.0250 mol
    • What is the molar mass of Na₂CO₃?
      106.0 g mol⁻¹
    • How do you calculate the mass of Na₂CO₃ required?
      Use m* = *n × *M*
    • What is the mass of Na₂CO₃ required for the standard solution?
      2.65 g
    • How can concentrations be expressed besides mol dm⁻³?
      • Concentrations can be expressed in g dm⁻³
      • Mass concentration is calculated from moles
    • What is the molar gas volume at RTP?
      24.0 dm³ mol⁻¹
    • What is the approximate temperature and pressure at RTP?
      20°C and 101 kPa
    • How do you convert between moles and gas volumes?
      Use n* = *V / *V*m
    • How do you calculate moles from gas volume in cm³ at RTP?
      n* = *V / 24 000
    • What is the amount of H₂ in 480 cm³ at RTP?
      0.0200 mol
    • What is the volume of 0.150 mol O₂ at RTP?
      3.60 dm³
    • What are the assumptions of an ideal gas?
      • Random motion
      • Elastic collisions
      • Negligible size
      • No intermolecular forces
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