| Date | May 2009 | Marks available | 1 | Reference code | 09M.3.sl.TZ2.C1 |
| Level | SL | Paper | 3 | Time zone | TZ2 |
| Command term | Describe | Question number | C1 | Adapted from | N/A |
Question
Alloys are important substances in industries that use metals.
Describe an alloy.
[1]
a.
Explain how alloying can modify the structure and properties of metals.
[2]
b.
Markscheme
homogeneous mixture of metals/a metal and non-metal;
a.
alloying element(s) disrupts regular/repeating (metal) lattice;
difficult for one layer to slide over another / atoms smaller than the metal cations can fit into the (holes of) metal lattice disrupting bonding;
can make metal harder/stronger/more corrosion resistant/brittle;
b.
Examiners report
Many candidates did not gain the mark as they omitted the required word homogeneous.
a.
Many candidates did not gain the mark as they omitted the required word homogeneous (a), but they could explain how alloying can modify the structure (b).
b.
