Thanks for your interest this product! I hope you and your students enjoy doing this activity
A small note:
The procedures say
“Using the chemical equations listed on your sheet, use your set of chemical formula cards to replicate the chemical equation on your desk.”
A link to the cards used can be found below as the original site (middleschoolscience.com) does not seem to be active any longer.
Should you choose not to print out and use the cards with your students, you can simply have them write out the equations on a sheet of paper or any alternative method you see fit.
This worksheet focuses on having student count the number of atoms for each element on the reactant side and the product side, then provide an explanation for whether or not that equation (as is) supports the law of conservation of mass. An example has been done for students to have an exemplar.
Good luck and happy learning!