Titration calculations

Question 1

Titres (cm³): rough 22.7, run 1 21.65, run 2 21.7. Ignoring the rough titre, calculate the mean titre from the concordant results (within 0.10 cm³), in cm³. Give 2 decimal places.

Answer cm³

Question 2

Which piece of equipment measures exactly 25.0 cm³ of alkali into the flask?

• A. a volumetric pipette
• B. a beaker
• C. a measuring cylinder
• D. a test tube

Question 3

25 cm³ of 0.1 mol/dm³ sodium hydroxide is neutralised by 15 cm³ of sulfuric acid. H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O. What is the concentration of the acid, in mol/dm³? Give 3 decimal places.

Answer mol/dm³

Question 4

Titres (cm³): rough 25.46, run 1 24.41, run 2 24.46. Ignoring the rough titre, calculate the mean titre from the concordant results (within 0.10 cm³), in cm³. Give 2 decimal places.

Answer cm³

Question 5

Why is the conical flask swirled during a titration?

• A. to change the indicator
• B. to mix the solutions so the end point is seen accurately
• C. to cool the flask
• D. to speed up evaporation

Question 6

25 cm³ of 0.2 mol/dm³ sodium hydroxide is neutralised by 40 cm³ of hydrochloric acid. HCl + NaOH → NaCl + H₂O. What is the concentration of the acid, in mol/dm³? Give 3 decimal places.

Answer mol/dm³

Question 7

Titres (cm³): rough 23.4, run 1 22.6, run 2 22.55. Ignoring the rough titre, calculate the mean titre from the concordant results (within 0.10 cm³), in cm³. Give 2 decimal places.

Answer cm³

Question 8

What does "concordant results" mean in a titration?

• A. the first titre only
• B. results with different indicators
• C. titres that are exactly 25 cm³
• D. titres that agree closely, usually within 0.10 cm³

Question 9

25 cm³ of 0.1 mol/dm³ sodium hydroxide is neutralised by 22.5 cm³ of hydrochloric acid. HCl + NaOH → NaCl + H₂O. What is the concentration of the acid, in mol/dm³? Give 3 decimal places.

Answer mol/dm³

Question 10

Titres (cm³): rough 23.88, run 1 23.13, run 2 23.18. Ignoring the rough titre, calculate the mean titre from the concordant results (within 0.10 cm³), in cm³. Give 2 decimal places.

Answer cm³

Question 11

Why is acid added dropwise near the end point?

• A. to avoid adding too much past the end point
• B. because drops react faster
• C. to make the indicator brighter
• D. to keep the burette full

Question 12

20 cm³ of 0.5 mol/dm³ sodium hydroxide is neutralised by 12.5 cm³ of hydrochloric acid. HCl + NaOH → NaCl + H₂O. What is the concentration of the acid, in mol/dm³? Give 3 decimal places.

Answer mol/dm³

Question 13

Titres (cm³): rough 22.69, run 1 21.94, run 2 21.94. Ignoring the rough titre, calculate the mean titre from the concordant results (within 0.10 cm³), in cm³. Give 2 decimal places.

Answer cm³

Question 14

Which piece of equipment measures exactly 25.0 cm³ of alkali into the flask?

• A. a test tube
• B. a measuring cylinder
• C. a volumetric pipette
• D. a beaker

Question 15

25 cm³ of 0.5 mol/dm³ sodium hydroxide is neutralised by 22.5 cm³ of hydrochloric acid. HCl + NaOH → NaCl + H₂O. What is the concentration of the acid, in mol/dm³? Give 3 decimal places.

Answer mol/dm³

Question 16

Titres (cm³): rough 25.16, run 1 24.61, run 2 24.61. Ignoring the rough titre, calculate the mean titre from the concordant results (within 0.10 cm³), in cm³. Give 2 decimal places.

Answer cm³