3.4.2 Converting between mol/dm³ and g/dm³

• In what context is g/dm³ typically used?

  Practical preparation of solutions
• In what context is mol/dm³ typically used?

  Chemical calculations
• What do both mol/dm³ and g/dm³ measure?

  Concentration of a solute in a solvent
• What does concentration (mol/dm³) represent?

  Amount of solute per liter of solution
• What is the formula for concentration in mol/dm³?

  concentration (mol/dm³) = mass (g) / (molar mass (g/mol) * volume (dm³))
• What are the steps to identify values needed for calculations?

  1. Read the question carefully
  2. List known values
  3. Identify the unknown
  4. Refer back to the formula
• What is molar mass (g/mol)?

  Weight of one mole of the solute
• What does mol/dm³ indicate about a solution?

  Number of moles of solute per liter
• What is the first step in rearranging the formula for concentration?

  Identify the term to solve for
• If you have 25 g of NaCl in 0.5 dm³ of water, what is the mass?

  25 g
• What does it mean to substitute values into a formula?

  Replacing each variable with its corresponding value
• What is the next step after substituting values into the formula?

  Perform the calculations to find concentration
• How would you express the concentration calculation using the given values?

  concentration = 15 g / (180 g/mol × 0.25 dm³)
• If you need to find the mass, which formula should you use?

  mass = concentration × molar mass × volume
• What does mass (g) refer to in the concentration formula?

  Total weight of the solute
• What does g/dm³ indicate about a solution?

  Mass of solute in grams per liter
• What is the difference between mol/dm³ and g/dm³?

  • mol/dm³: Moles of solute per liter
  • g/dm³: Grams of solute per liter
• What values are typically looked for in a chemistry problem?

  • Concentration
  • Mass
  • Molar mass
  • Volume
• What is the formula for concentration?

  Concentration = mass / (molar mass × volume)
• How do you calculate the mass of a solute given concentration and volume?

  Multiply concentration, molar mass, and volume
• What does identifying the unknown involve?

  Determining which value you need to calculate
• What is the first step before doing calculations?

  Identify what you already know
• How do you isolate the desired variable in a formula?

  Use basic algebra to rearrange
• What is the first step after knowing the formula and given values?

  Substitute them into the formula
• What are the steps to rearranging the formula for concentration?

  1. Identify the term to solve for
  2. Rearrange the formula
  3. Substitute given values
  4. Perform the calculation
• If the volume is doubled, how does that affect the mass calculation?

  The mass will also double
• What are the key terms and their units in the concentration formula?

  • Concentration: mol/dm³
  • Mass: g
  • Molar Mass: g/mol
  • Volume: dm³
• Why is it important to read the question carefully?

  To find concentration, mass, molar mass, and volume
• What does volume (dm³) represent in the concentration formula?

  Total volume of the solution in liters
• What should you list after reading the question?

  Known values
• What do you do after identifying known and unknown values?

  Rearrange the formula to solve for concentration
• What is the practice problem for calculating concentration provided in the material?

  • Calculate concentration of 10 g of NaOH
  • Molar mass = 40 g/mol
  • Dissolved in 0.25 dm³ of water
• If 20 g of NaCl is dissolved in 0.5 dm³ of water, what is the first step to find concentration?

  Substitute values into the formula
• How do you calculate the concentration after finding the product of molar mass and volume?

  Divide mass by the result