5.1 Moles 2

Question 1

what unit do we use - cm^3 or dm^3

Answer 1

dm cubed

Question 2

how to convert from cm to dm cubed

Answer 2

divide by 1000

Question 3

how to covert from dm to cm cubed

Answer 3

multiply by 1000

Question 4

volume equation

Answer 4

moles = volumes(dm)/24

Question 5

concentration equation

Answer 5

concentration = moles/volume(dm cubed)

Question 6

what is titration used for

Answer 6

to measure the volume of acid needed to neutralise a particular volume of alkali

Question 7

what equipment is used in titration

Answer 7

volumetric pipette - measures 25 cm^3 very accurately
burette - measures any volume to the nearest 0.05cm^3

Question 8

set up for titration

Answer 8

1. use a volumetric pipette to place 25cm^3 of the unknown alkali into a conical flask
2. add either phenolphthalein or methyl orange
3. fill a burette with a known acid and clamp it above the conical flask
4. measure initial volume of acid in the burette
5. use the burette to add acid into the conical flask while swirling it
6. as soon as the colour changes close the burette tap (will be acidic colour of indicator)
7. measure final volume of known acid
8. calculate titre (final-initial volume)
9. repeat to get concordant and take an average