Sahil watched a demonstration in which a scientist combined two substances in a sealed container and analyzed the results. The ending substances did not look the same as the starting substances. Sahil was given a diagram with the repeating groups of atoms that make up the starting substances, plus information about the properties of the starting and ending substances. He created a model of the repeating groups of atoms that might make up the two ending substances.

amira's model correctly demonstrates how the properties changed with the rearrangement of the atoms. However not all atoms are accounted for. There is a missing reactant.

Explanation:

Samira's model correctly demonstrated how the atoms in two compounds reacted to form two new products. However, the elements present in the reactants side should be the elements that make up the new products in the product side. But as the diagram shows, Sameera has mistakenly added a new element to one of her products which will be wrong.