- Here is the picture of products.
- The mass of the bag: 1.9g
- The mass of the chemical A: 2.3g
- The mass of the chemical B: 1.9g
- The mass of the chemical C: 0.5g
- The total mss of the products: 5.6g-1.9=3.7g
- The total mass of the reactants: 2.3g+1.9+0.5g=4.7g
We lost the mass. I think the reason must be there still some chemicals did not react completely, or even had some chemicals left in the weight boat.