C3 Quantitative Chemistry

Question 1

Avogadro’s Constant

Answer 1

6.0 x 10^23 particles per mole

Question 2

Molar Mass Formula

Answer 2

mass = Mr x moles

Question 3

Percentage Yield

Answer 3

mass produced/maximum mass producible

Question 4

Reasons why the Percentage Yield is less than 100%

Answer 4

• Reactants/products left on apparatus during transfer
• Some escape during the reaction process
• Reactants react incompletely
• Reaction may be reversible

Question 5

Atom Economy

Answer 5

Mr of desired product/Mr of all reactants

Question 6

Gas Volume

Answer 6

1 mol = 24 dm^3 at room temperature and pressure

Question 7

Unit Conversion

Answer 7

1 dm^3 = 1000 cm^3

Question 8

Concentration Formula

Answer 8

Concentration (mol/dm^3) = Moles/Volume

Question 9

Uncertainty

Answer 9

Remove anomalies
Find mean
± Range/2 or the largest difference

Question 10

Titration

Answer 10

• Acid in clean, dry 100cm^3 beaker
• Rinse burette with acid, place on burette holder.
• Fill burette to 0.0cm^3 line (bottom of meniscus)
• Rinse out conical flask with water.
• Collect alkali with clean, dry 100cm^3 beaker.
• Rinse out 25.0cm^3 pipette
• Transfer 25.0cm^3 alkali to conical flask
• Place conical flask on white tile
• Add 4 drops of phenol red indicator
• Add acid from burette until indicator changes colour from purple to orange.
• Table