Astudent performs an experiment that produces solid sodium chloride. he uses four different catalysts and lets the reaction run for two minutes, and then removes the sodium chloride product. which is the best way for him to make a consistent measurement that would show the different amounts of sodium chloride produced?

If these were the missing choices:
Measure the product separately on four different scales.
Measure all of the product together and divide by four.
Measure the four products separately, but using the same scale each time.
Measure the amount of sodium chloride in one sample every 10 seconds.

My
MEASURE THE FOUR PRODUCTS SEPARATELY, BUT USING THE SAME SCALE EACH TIME.

This is to ensure that the scale measurement is consistent. It is easier to determine the changes in amount if all use the same scale rather than using different scale for each product.