When will be the appropriate time to implement the virtual lab for this unit? Would it be after the assessment?

Timothy - I consulted with our Chemistry team and they feel that this particular lab can be taught at any point after the Mass Spectometry and Atomic Mass topic has been taught. Or you can use it at the end of the unit to help review the concepts in the unit. - Melissa

Sounds good! Another question: when the unit plan indicated that the unit is 6 days long, how long are these class periods?

We estimate it to be one class period that is about 50 minutes long.