5.1 Moles 2

Question 1

What is volume of gas measured in?

Answer 1

cubic metres

Question 2

What is volume of gas measured in for mole calulations?

Answer 2

cubic decimetres

Question 3

What is the scale factor between cm cubed and dm cubed?

Answer 3

1000

Question 4

cubic centimetres -> cubic decimetres

Answer 4

divide by 1000

Question 5

cubic decimetres -> cubic centimetres

Answer 5

multiply by 1000

Question 6

Equation for moles of a gas?

Answer 6

moles = volume / 24 cubic decimetres

Question 7

State the equation linking moles, volume and concentration

Answer 7

moles = concentration x volume

Question 8

What is the concentration of a solution a measure of?

Answer 8

how much solute dissolved per unit volume

Question 9

What is the equation for concentration of a solution?

Answer 9

concentration = moles / volume

Question 10

What is titration used for?

Answer 10

neutralise a particular volume (acid/alkali)

Question 11

Name the two special pieces of equipment for titration

Answer 11

volumetric pipette
burette

Question 12

What is the volumetric pipette for?

Answer 12

measuring 25cm cubed accurately

Question 13

What is the burette for?

Answer 13

measuring a volume to the nearest 0.05 cm cubed

Question 14

Why is universal indicator not used in titration?

Answer 14

colour change is not sharp/defined

Question 15

Which indicator should be used in titration?

Answer 15

phenolphthalein/methyl orange

Question 16

Why is a pipette not suitable for adding acid/alkali to complete neutralisation?

Answer 16

pipette only measures on volume - 25 cm cubed

Question 17

What are concordat results?

Answer 17

differ from each other by 0.2 cm cubed or less

Question 18

What is the first step of set up for titration?

Answer 18

use volumetric pipette
25 cm cubed of unknown into conical flask

Question 19

Where does the 25 cubic cm of unknown go in step 1?

Answer 19

conical flask

Question 20

What is added to the conical flask in step 2?

Answer 20

indicator

Question 21

What is the burette filled with in step 3 of set up?

Answer 21

known solution

Question 22

Where should the burette of known solution be clamped?

Answer 22

above the conical flask

Question 23

In step 1 of usage, what should the volume of known be measured to?

Answer 23

nearest 0.05 cubic cm

Question 24

What is the role of the burette in step 2 of usage?

Answer 24

add known solution to conical flask

Question 25

How should the known solution be added to the acid?

Answer 25

drop-by-drop, swirling the flask

Question 26

When should the burette tap be closed?

Answer 26

colour change in conical flask

Question 27

How do you calculate titre?

Answer 27

final volume - initial volume