Question: the is the si unit that expresses the amount of substance
[{'answer': 'mole', 'provenance': [{'wikipedia_id': '759264', 'title': 'Amount of substance', 'start_paragraph_id': 1, 'start_character': 149, 'end_paragraph_id': 1, 'end_character': 153, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]