Titrations

• What are titrations used for?

  To find out concentrations
• What do titrations allow you to determine about an acid?

  How much acid is needed to neutralize
• What is the procedure for using a pipette in titrations?

  1. Measure out a set volume of alkali into a flask.
  2. Add a few drops of an indicator.
  3. Use a burette to add acid slowly.
  4. Swirl the flask regularly.
  5. Stop when the endpoint is reached.
• What should you add to the alkali in a titration?

  A few drops of an indicator
• What happens when you swirl the flask during a titration?

  The solution mixes thoroughly
• How should you add acid to the alkali during titration?

  Slowly, drop by drop
• What indicates that the endpoint of a titration has been reached?

  The color change of the indicator
• What color does phenolphthalein turn in an acidic solution?

  Colorless
• What happens to the color of the solution as you approach the endpoint in a titration?

  The color changes gradually
• What should you record during a titration?

  The volume of acid used
• How can you calculate the concentration of a solution using titration results?

  Using the volume and molarity of titrant
• What are the steps to calculate concentration from titration results?

  1. Record the volume of titrant used.
  2. Note the molarity of the titrant.
  3. Use the formula:

  $\text{Concentration} =$$\frac{\text{Number of moles}}{\text{Volume of solution}}$

  1. Calculate the concentration of the unknown solution.
• What is the formula for concentration in mol/dm³?

  Concentration = number of moles / volume
• How is concentration expressed in titration?

  In moles per cubic decimeter
• If you have 0.100 mol/dm³ of sulfuric acid, how much volume is needed for titration?

  25.0 cm³ for 0.100 mol
• What does it mean if the indicator changes color during titration?

  The reaction has reached its endpoint
• What is the importance of repeating titration experiments?

  • Ensures accuracy and reliability of results
  • Helps identify any anomalies in data
  • Confirms consistency in measurements
• What is the final step after completing titration?

  Record the results
• Why is it important to use the same method in repeated titrations?

  To ensure consistent results
• How do you calculate the mean of titration results?

  Average the consistent results
• What is the concentration of a solution with 1 mole in 1 dm³?

  1 mol/dm³
• What does a higher concentration indicate in a solution?

  More solute is present
• If you have a solution with a concentration of 2 mol/dm³, how many moles are in 2 dm³?

  4 moles
• How does the concentration of a solution affect its properties?

  Higher concentration can increase reactivity
• What can you use to calculate the concentration of the alkali?

  The results of a titration experiment
• What is the purpose of the titration experiment mentioned?

  To calculate the concentration of the alkali
• How much volume of sulfuric acid is needed to neutralize the alkali?

  25.0 cm³ of 0.100 mol dm⁻³ sulfuric acid
• What is the balanced equation for the reaction between sodium hydroxide and sulfuric acid?

  2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O
• How do you find the concentration of the alkali in mol dm⁻³?

  Number of moles divided by volume
• How many moles of sulfuric acid are used in the titration?

  0.000250 moles of H₂SO₄
• How many moles of sodium hydroxide are required to react with 0.000250 moles of sulfuric acid?

  0.000500 moles of NaOH
• What is the final concentration of the alkali in mol dm⁻³?

  0.167 mol dm⁻³
• What is the molar mass of sodium hydroxide (NaOH)?

  40 g/mol
• How do you convert concentration from mol dm⁻³ to g dm⁻³?

  Multiply by the molar mass
• What is the molar mass of sulfuric acid (H₂SO₄)?

  98 g/mol
• How do you convert 0.167 mol dm⁻³ of NaOH to g dm⁻³?

  6.68 g dm⁻³
• What is the relationship between the concentration of the alkali and the volume used in the titration?

  Concentration increases as volume decreases
• What is the equation for the reaction of hydrochloric acid with sodium hydroxide?

  HCl + NaOH → NaCl + H₂O
• How many moles of sodium hydroxide are needed to neutralize 0.50 mol dm⁻³ hydrochloric acid in 15 cm³?

  0.0075 moles of NaOH
• What is the volume of sodium hydroxide needed to neutralize 15 cm³ of 0.50 mol dm⁻³ hydrochloric acid?

  15 cm³ of NaOH