IB skill practice

Calculate entropy changes and predict entropy trends

Paper 1, Paper 2 5 marks Difficulty 5

Entropy of the universe

For a process in a Auckland reaction-rate practical, \(\Delta S_{\text{system}}=78\,\text{J K}^{-1}\) and \(\Delta S_{\text{surroundings}}=-12\,\text{J K}^{-1}\). Calculate \(\Delta S_{\text{universe}}\). Enter the answer and choose the interpretation that matches the HL chemistry evidence.

Worked practice: chemistry evidence and answer

Use the chemical evidence first, then enter the result and interpretation that match it.