Question #4cdbc

2 Answers
Jun 12, 2016

There are indeed 7 oxygen atoms in this equation.

Explanation:

I edited your question to make it more understandable. Maybe now you can see that there are indeed 7 oxygen atoms?

Lets first see how much of each element is in #2CO_2# :
you should read this as: # 2*(C + O_2)#
which is similar to: # 2*C + 2* (O+O)#
so there are #2# carbon atoms (#C#) and #2 * 2 = 4# oxygen (#O#) atoms.

Than the elements in the second part #3H_2O# :
this you should read as: #3* (H_2 + O)#
which is similar to: #3 * (H + H) + 3 * O#
so there are #6# hydrogen (#H#) atoms and #3# oxygen (#O#) atoms

In total: #4 * O# in #2CO_2# and #3 * O# in #3H_2O# = #7# oxygen atoms

Jun 12, 2016

There are seven Oxygen atoms in the reaction.

Explanation:

The numbers in front of the chemical formula indicate how many lots of that compund you have. The numbers apply to each element in the compound.

The example states:
#2CO_2+3H_2O#

If the numbers apply to each element, and there is a small subscript number next to it, then you multiply them together.

For example, #2CO_2#. Here there are 2 carbon atoms, as there is no number, which means that you only have one, and since there are 2 lots of #CO_2#, then you will have 2 carbon atoms and 4 oxygen atoms.

If we then apply this to the water molecules, we find that there are a total of 2 carbon atoms, 7 oxygen atoms, and 6 hydrogen atoms.