Identical pieces of magnesium are added to two beakers, A and B, containing hydrochloric acid. Both acids have the same initial temperature but their volumes and concentrations differ.

Which statement is correct?

A.     The maximum temperature in A will be higher than in B.

B.     The maximum temperature in A and B will be equal.

C.     It is not possible to predict whether A or B will have the higher maximum temperature.

D.     The temperature in A and B will increase at the same rate.

A

One G2 comment stated although this was a good question, it would be challenging for many SL candidates. In fact, although this was the fifth hardest question on the entire paper, 43% of candidates still managed to get the question correct.