Question

Supposed 10 atoms of carbon react with 20 atoms of oxygen to form 10 molecules of carbon dioxide. According to the law of conservation of matter, how many atoms are present in this reaction.
A 30
B 20
C 10
D 15

Answer 1

The law of conservation of matter states that matter cannot be created or destroyed in a chemical reaction; it can only be rearranged. Therefore, the total number of atoms before and after the reaction should be the same.

Before the reaction:
10 atoms of carbon
20 atoms of oxygen

After the reaction:
10 molecules of carbon dioxide

Each molecule of carbon dioxide consists of 1 atom of carbon and 2 atoms of oxygen.

10 molecules of carbon dioxide x (1 carbon atom + 2 oxygen atoms) = 10 carbon atoms + 20 oxygen atoms

Therefore, the total number of atoms in this reaction is 10 carbon atoms + 20 oxygen atoms = 30 atoms.

So, the correct answer is:

A) 30