what is the answer is it 6

Question

2. How many oxygen atoms are indicated on the right side
of this balanced chemical equation?
4 Cr(s) + 3 O2( g)h2 Cr2O3( g)

Answer 1

I'm not sure if you wrote the whole equation?  It looks like your h is supposed to be representing the yield arrow?  Anyways, you always multiple the coefficient by the subscript to get the total.  If there is more than one compound with oxygen in it, you multiple the coefficient by the subscript for each compound and then add them together. 

For example:  if you have 3O₂,   then there are 3(2) = 6 oxygens.

For example: if you have 3O2   + 2CO₂,   then there are 3(2) + 2(2)  = 6 +4 = 10 oxygens

 

If you have a parentheses, such as (PO₄)₃ , then you also have to multiple the 4(3) = 12 oxygens

For example: 2Ca₃(PO₄)_2, then you will have (4)(2)(2) = 16 oxygens.

 

Hope that helps.  Also remember that the number of oxygens should be equal on both sides of the equation.