Volumes of solutions in reactions

• What is the unit for the amount of substance?

  The mole
• How can the number of particles in a substance be found?

  Using the Avogadro constant
• What does the mass of the product in a chemical reaction depend on?

  The mass of the limiting reactant
• What is a solute in a solution?

  • The dissolved substance in a solution
  • It is combined with a solvent to form a solution
• What does the concentration of a solution indicate?

  How much of a substance is dissolved in water
• How is the concentration of a solution calculated?

  Concentration in mol/dm³ = amount of solute in mol / volume in dm³
• What is the amount of sodium hydroxide in 25.0 cm³ of solution with a concentration of 0.1 mol/dm³?

  0.0025 mol
• How do you convert 25.0 cm³ to dm³?

  25.0 cm³ = 0.025 dm³
• How do you calculate the mass of NaOH in 25.0 cm³ of solution if M_r = 40 g?

  Mass = amount × relative formula mass = 0.0025 × 40 = 0.1 g
• What is the process to calculate the concentration of a solution when volumes of two solutions that react completely are known?

  1. Convert volumes from cm³ to dm³
  2. Calculate the amount of solute in moles using concentration and volume
  3. Use the stoichiometry of the reaction to find the amount of the other solute
  4. Calculate the concentration of the other solution
• What is the concentration of NaOH if 25.0 cm³ of HCl with a concentration of 1.0 mol/dm³ reacts with 20.0 cm³ of NaOH?

  1. 25 mol/dm³
• What is the relationship between the amount of HCl and NaOH in the reaction?

  1 mol of HCl reacts with 1 mol of NaOH
• How do you find the amount of HCl in moles from its concentration and volume?

  Amount of HCl in mol = concentration in mol/dm³ × volume in dm³
• What is the formula for calculating concentration?

  Concentration = amount of solute in mol / volume in dm³
• What does the term "limiting reactant" refer to in a chemical reaction?

  The reactant that is completely consumed first, limiting the amount of product formed
• How does the concentration of a solution affect the number of particles present?

  A higher concentration means more particles of the substance are present
• What is the relative formula mass (M_r) of sodium hydroxide (NaOH)?

  40 g
• What is the significance of the Avogadro constant?

  It represents the number of particles in one mole of a substance
• How do you convert a volume from cm³ to dm³?

  Divide the volume in cm³ by 1000
• What is the relationship between the volume of a solution and its concentration?

  As the volume increases, the concentration decreases if the amount of solute remains constant