Date | November 2016 | Marks available | 1 | Reference code | 16N.3.sl.TZ0.4 |
Level | SL | Paper | 3 | Time zone | TZ0 |
Command term | Calculate | Question number | 4 | Adapted from | N/A |
Question
A student wanted to determine the formula of indium sulfate. She applied an electrical current of 0.300A to an aqueous solution of indium sulfate for 9.00 × 103 s and found that 1.07 g of indium metal deposited on the cathode.
Calculate the charge, in coulombs, passed during the electrolysis.
Calculate the amount, in mol, of electrons passed using section 2 of the data booklet.
Calculate the mass of indium deposited by one mole of electrons.
Calculate the number of moles of electrons required to deposit one mole of indium. Relative atomic mass of indium, Ar=114.82.
Deduce the charge on the indium ion and the formula of indium sulfate.
Markscheme
«0.300A × 9.00 × 103 s =» 2.70 × 103 «C»
«mol e− = =» 2.80 × 10−2 «mol»
«=» 38.2 «g»
« e− =» 3.01/3.00 «mol e−»
In3+ /3+ AND In2(SO4)3
Do not accept “+3/3”