amount of substance (2)

Question 1

concentration equation

Answer 1

number of moles over volume

Question 2

concentration

Answer 2

mol dm3

Question 3

cm3 to dm3

Answer 3

divide by 1000

Question 4

dm3 to cm3

Answer 4

times 1000

Question 5

dm3 to m3

Answer 5

divide by 1000

Question 6

m3 to dm3

Answer 6

times 1000

Question 7

percentage atom economy

Answer 7

mr of product over mr of reactants times 100

Question 8

percentage yield

Answer 8

mass of product over theoretical mass times 100

Question 9

mg to g

Answer 9

divide by 1000

Question 10

concordant titre

Answer 10

Titres that are within 0.1 cm3 of each other

Question 11

The student rinses the burette with deionised water before filling with
sodium hydroxide solution.
State and explain the effect, if any, that this rinsing will have on the value of
the titre

Answer 11

Titre value would increase
Because the sodium hydroxide solution would be more dilute

Question 12

State the importance of percentage yield and percentage atom economy when
choosing the method used to make a compound.

Answer 12

PY = idea of getting as much product as possible in the reaction
pae = idea of maximising the mass of reactants

Question 13

State why the student should use sodium hydroxide solution rather than
water for the final rinse of the burette

Answer 13

use of water would dilute the NaOH

Question 14

The student used a wash bottle containing deionised water when
approaching the end-point to rinse the inside of the conical flask.
Explain why this improved the accuracy of the titration.

Answer 14

it ensures all acid would be on the sides of the flask