A compound containing 3 atoms of carbon and 8 atoms of hydrogen is combined in a reaction with oxygen molecules. The two end products of this equation are carbon dioxide and water. Which chemical or element will have the largest number of moecules?

Since this is not my area of expertise, I searched Google under the key words "8 hydrogen 3 carbon atoms" to get this:

http://www.google.com/search?client=safari&rls=en&q=8+hydrogen+3+carbon+atoms&ie=UTF-8&oe=UTF-8

In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.

To determine which chemical or element will have the largest number of molecules, we need to calculate the number of molecules for each compound.

First, let's calculate the number of molecules for carbon dioxide (CO2). To do this, we need to convert the given number of atoms (3 atoms of carbon) into moles, using the molar mass of carbon (12.01 g/mol), and then convert the moles into molecules using Avogadro's number (6.022 x 10^23 molecules/mol).

3 atoms of carbon x (1 mol/6.022 x 10^23 atoms) x (6.022 x 10^23 molecules/mol) = 3 molecules of carbon dioxide (CO2).

Next, let's calculate the number of molecules for water (H2O). We have 8 atoms of hydrogen, so we'll follow the same steps as before.

8 atoms of hydrogen x (1 mol/6.022 x 10^23 atoms) x (6.022 x 10^23 molecules/mol) = 8 molecules of water (H2O).

Since carbon dioxide has 3 molecules and water has 8 molecules, water (H2O) will have the largest number of molecules in this reaction.