Question

which model illustrates the law of conservation of mass?

Explanation:

Step1: Count atoms in reactants

In each model, count the number of dark - colored atoms (let's assume they are one type of atom, say \(A\)) and light - colored atoms (say \(B\)) on the left - hand side (reactants). For all models, there are \(2\) \(A\) atoms and \(2\) \(B\) molecules (so \(4\) \(B\) atoms) in the reactants.

Step2: Count atoms in products

• Model A: There is \(1\) \(A\) atom and \(2\) \(B\) atoms in the product. Atoms are not conserved.
• Model B: There are \(3\) \(A\) atoms and \(2\) \(B\) atoms in the products. Atoms are not conserved.
• Model C: There are \(2\) \(A\) atoms and \(2\) \(B\) atoms in the products. Atoms are not conserved.
• Model D: There are \(4\) \(A\) atoms and \(4\) \(B\) atoms in the products. Atoms are conserved.

Answer:

D. Model D