Suppose 10 atoms of carbon (C) react with 20 atoms of oxygen (o) to form 10 molecules of carbon dioxide (CO2). According to the law of conservation of matter, how many atoms are present in this reaction?

Question

A. 15
B. 30
C. 20
D. 10

Answer 1

In this reaction, 10 atoms of carbon (C) react with 20 atoms of oxygen (O) to form 10 molecules of carbon dioxide (CO₂).

To determine the total number of atoms present in the reaction, we can break it down as follows:

1. Reactants:

   • Carbon: 10 atoms
   • Oxygen: 20 atoms
   • Total atoms in reactants = 10 (C) + 20 (O) = 30 atoms

2. Products:

   • In the product molecules of CO₂, each molecule contains 1 carbon atom and 2 oxygen atoms. Since there are 10 molecules of CO₂:
     • Carbon: 10 molecules x 1 atom/molecule = 10 atoms
     • Oxygen: 10 molecules x 2 atoms/molecule = 20 atoms
     • Total atoms in products = 10 (C) + 20 (O) = 30 atoms

According to the law of conservation of matter, the total number of atoms in the reactants must equal the total number of atoms in the products.

Thus, the total number of atoms present in the reaction is:

30 atoms.

The correct answer is B. 30.