Moles II

Question 1

what is volume measured in

Answer 1

• dm^3 (more commonly)
  -cm^3

Question 2

how to turn cm^3 into dm^3

Answer 2

divide by 1000

Question 3

how to turn dm^3 into cm^3

Answer 3

multiply by 1000

Question 4

how to find moles of a gas

Answer 4

volume (dm^3)
———————
24 dm^3

Question 5

how to find conc of a solution (mol/dm^3)

Answer 5

moles(mol) of solute/
volume (dm^3) of solvent

Question 6

what is a titration

Answer 6

practical method to measure volume of acid needed to neutralise particular volume of alkali, or vice-versa

Question 7

what special pieces of equipment needed for titration

Answer 7

• volumetric pipette
• burette

Question 8

what is volumetric pipette used for

Answer 8

• measures out 25cm^3 very accurately
• useless at measuring any other volume

Question 9

what is burette used for

Answer 9

-measures any volume to nearest 0.05cm^3

Question 10

how to carry out titration

Answer 10

1-use volumetric pipette to place 25cm^3 of unknown alkali into conical flask
2-add few drops of phenolphthalein or methyl orange into flask
3- fill burette with known acid and clamp above flask
4-measure initial volume of known acid to nearest 0.05cm^3
5-add acid drop by drop to while swirling flask
6-close burette as soon as colour in flask changes
7-measure final volume of known acid in burette
8- calculate titre (final volume-initial volume)
9- repeat to get concordant (within 0.2) titres