Acid - Base Titrations

Question 1

What is volumetric analysis?

Answer 1

A process that uses the volume and concentration of one chemical reactant to determine the concentration of another unknown solution

It commonly involves titration.

Question 2

What is the most commonly used technique in volumetric analysis?

Answer 2

Titration

Question 3

What equipment is used to measure volumes in volumetric analysis?

Answer 3

Volumetric or graduated pipette and a burette

Question 4

What must be prepared before performing a titration?

Answer 4

The standard solution

Question 5

List key pieces of apparatus used in volumetric analysis.

Answer 5

• Beaker
• Burette
• Volumetric Pipette
• Conical Flask
• Volumetric Flask

Question 6

What are volumetric solutions?

Answer 6

Solutions whose concentrations are known precisely

Question 7

How should solutions be prepared to minimize measurement uncertainties?

Answer 7

Using three decimal place balances and volumetric flasks

Question 8

What is the definition of concentration?

Answer 8

The amount of solute dissolved in a solvent to make 1 dm³ of solution

Question 9

What is the solute in a solution?

Answer 9

The substance that dissolves in a solvent to form a solution

Question 10

What is the solvent usually used in solutions?

Answer 10

Water

Question 11

Define a concentrated solution.

Answer 11

A solution that has a high concentration of solute

Question 12

Define a dilute solution.

Answer 12

A solution with a low concentration of solute

Question 13

What are the three common ways to express concentration?

Answer 13

• Moles per unit volume
• Mass per unit volume
• Parts per million

Question 14

What is the precision of burettes commonly marked to?

Answer 14

0.10 cm³

Question 15

What is the uncertainty recorded for a burette reading?

Answer 15

±0.05 cm³

Question 16

What is the equivalence point in a titration?

Answer 16

The point when the two solutions have reacted completely

Question 17

What is used to indicate the end point of a titration?

Answer 17

An indicator

Question 18

What is the purpose of placing a white tile under the conical flask during titration?

Answer 18

To make it easier to see the colour change

Question 19

What is the typical volume measured with a volumetric pipette for titration?

Answer 19

Usually 20 or 25 cm³

Question 20

What should be done as the titration approaches the end point?

Answer 20

Slow the flow of the burette and add the solution dropwise

Question 21

What are concordant results?

Answer 21

Results that are within 0.1 cm³ of each other

Question 22

How should initial and final burette readings be recorded?

Answer 22

To a precision of ±0.05 cm³

Question 23

What is the titre in a titration?

Answer 23

The volume delivered, calculated and recorded to an uncertainty of ±0.10 cm³

Question 24

How is percentage uncertainty calculated?

Answer 24

By comparing the significance of an absolute uncertainty on a measurement

Question 25

True or False: Percentage error compares a result to a literature value.

Answer 25

True

Question 26

What happens when adding or subtracting measurements?

Answer 26

Add together the absolute measurement uncertainties

Question 27

What is the relationship between moles, concentration, and volume?

Answer 27

Number of moles (mol) = concentration (mol dm⁻³) x volume (dm³)

Question 28

How do you calculate the mass of solute in a solution?

Answer 28

mass of solute (g) = number of moles (mol) x molar mass (g mol⁻¹)

Question 29

colours of phenolphthalein

Answer 29

acid - colourless
alkali - pink

Question 30

colours of methyl orange

Answer 30

acid - red
alkali - yellow

Question 31

colours of universal indicator

Answer 31

acid - red
alkali - blue