Question: how many atoms of carbon graphite are present in the pencil mark?
Answer: ' Learners will need to know that a pencil 'lead' is graphite, a form of carbon, and that 12 g of carbon contains 6.02 x 1023 carbon atoms. Use of 6.02 x 1023 (602 sextillion) is likely to be new information for learners. The learners then try to solve this problem for themselves using paper, a pencil and a balance.