Law of Conservation of Matter Quick Check

1 of 41 of 4 Items
Question
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?(1 point)
Responses

30
30

20
20

15
15

10
10
Skip to navigation

1 answer

According to the law of conservation of matter, the total number of atoms before a chemical reaction must equal the total number of atoms after the reaction.

In this scenario:

  • There are 10 atoms of carbon (C).
  • There are 20 atoms of oxygen (O).

So, the total number of atoms before the reaction is:

10 (C) + 20 (O) = 30 atoms.

After the reaction, you form 10 molecules of carbon dioxide (CO2), which consists of 1 carbon atom and 2 oxygen atoms per molecule. Thus, in 10 molecules of CO2, there are:

  • 10 carbon atoms (from 10 CO2 molecules)
  • 20 oxygen atoms (since 2 O per molecule x 10 CO2 molecules)

Calculating the total after the reaction gives:

10 (C) + 20 (O) = 30 atoms.

Therefore, the total number of atoms present in this reaction is 30.