Amount of substance

Question 1

Avogadro constant definition

Answer 1

Number of atoms in 12g C12

Question 2

Number of particles equation

Answer 2

Moles x avagardos constant

Question 3

Ar definition

Answer 3

Average mass of an atom of an element/ 1/12th the mass of C12

Question 4

Percentage yield

Answer 4

Actual yield/theoretical yield x100.

Question 5

Importance of percentage yield

Answer 5

Importance: Increases the amount of product that is made from the reactants, can be increased by making improvement in experimental technique.

Question 6

Atom economy

Answer 6

mass of desired product/ total mass of reactants x100
(mr/mr x100)

Question 7

titration accuracy

Answer 7

• remove any air bubbles- volume will be counted in burette reading
• remove funnel- solution drops could fall from funnel into burette affecting burette reading.
• rinse with distilled water- ensures all reactants mix and no reagent is unreacted. Moles remains the same.

Question 7

Standard solution

Answer 7

Transfer known mass of solid. weigh sample bottle cotaining solid on a balance. Transfer the beaker to re-weigh sample bottle. record difference in mass. Dissolves in water, add distilled water, stir with a glass rod, until all has dissolved. Transfer to volumetric flask using funnel with washings, make up to 250cm^3. Invert to mix

Question 8

Percentage error and how to reduce it

Answer 8

error of equipment/ amount measured x 100
How to reduce it: Increase the concentration of solution in conical flask, decrease conc of solution in burette.

Question 9

Ideal gas equation

Answer 9

pv=nrt

Question 10

finding mean titre

Answer 10

Use only concordant results, values that are within 0.1 of each other, add together and divide by how many there are.