A graphic organizer called the [Mole Wheel Handout] or [Level 2 Mole Wheel] has been used to help in determining the appropriate equation/conversion factor for the problems. Using the Mole Wheel, one sees that all the One Step Calculations are calculations that either goes from the outside of the wheel (on one spoke of the wheel) to the mole (the hub of the wheel) or visa versa.
The next logical question is, Why is one limited to go from the spoke (mass, or number of particles, or volume) to the hub (the mole)? Why can't one go from one spoke to another spoke?
For example, why can't one ask the question, What is the mass of 42.5L of CO2 gas at STP?
Of course, the answer is one can answer this question. Here, it is called a Two Step Mole Calcuations.
The procedures for Two Step Mole Calculation (using the Mole Wheel as guide) are the same as any math problem in class and just an extension of One Step Mole Calculation.
The step are the following:
1. From problem/question, find known information (locate on Mole Wheel)
2. From problem/question, find what one is looking for (locate on Mole Wheel)