Supposed to in advance of carbon reactor 20 items of oxygen to form 10 molecules of carbon dioxide according to the low conversation of matter. How many atoms are present in this reaction?

In the reaction of 20 oxygen atoms combining with 10 carbon atoms to form 10 molecules of carbon dioxide, we need to keep track of the atoms for each element.

20 oxygen atoms will combine with 10 carbon atoms:

Oxygen atoms: 20
Carbon atoms: 10

When these atoms combine to form carbon dioxide (CO2), each molecule contains 1 carbon atom and 2 oxygen atoms. So, for 10 molecules of CO2:

Carbon atoms: 10
Oxygen atoms: 10 x 2 = 20

Therefore, in total, there are:
- 20 oxygen atoms
- 10 carbon atoms

So, in this reaction, there are 20 + 10 = 30 atoms present.