5.1 Moles II

Question 1

how to carry out an acid-alkali tritiation

Answer 1

• fill​ ​burette​ ​to​ ​100cm3​ ​​with​ ​acid​ ​with​ ​the​ ​
• use pipette to add 25cm3​ of alkali into a conical flask
• add a few drops of a suitable indicator to the conical flask
• add​ ​acid​ ​from​ ​burette​ ​to​ ​alkali​ ​until​ ​end-point​ ​is​ ​reached​
• titre (volume of acid needed to exactly neutralise the acid) is the difference
  between​ ​the​ ​first​ ​(100cm3​ )​ ​​and​ ​second​ ​readings​ ​on​ ​the​ ​burette)
• repeat ​the​ ​experiment​ ​

Question 2

concentration of solution formula

Answer 2

mass of solute / volume

Question 3

mass =

Answer 3

concentration x vol

Question 4

24dm^3 to cm^3

Answer 4

x1000

Question 5

always convert

Answer 5

cm to dm

Question 6

volume =

Answer 6

moles x 24

Question 7

moles =

Answer 7

vol / 24

Question 8

how to calculate empirical formula

Answer 8

• lay out table with elements
• find mass, RAM, mol, ratio
• use ratio to find empirical formula

Question 9

determine formula of metal oxide by combustion or reduction

Answer 9

• weigh pure magnesium
• heat magnesium to burning in crucible to form magnesium oxide (reacts with oxygen in air)
• weight mass of MgO
  mass oxygen = mass MgO - mass O