N2 (g) + 3h2 (g) --> 2 nh3 (g) the equation above is the equation for the haber process. in a certain reaction, you start with 6.0 moles of nitrogen and 10.0 moles of hydrogen. how many moles of ammonia will be produced in the reaction?

For ever 1 mole of nitrogen you need 3 moles of hydrogen to make 2 moles of Ammonia.
We only have 10 moles of hydrogen so that is the limiting as there is more nitrogen then hydrogen in this particular case.
Therfore the ratio is 2 ammonia to 3 hydrogen [2:3]
Do 2/3which is 0.6667. This is how many moles of ammonia you get per mole of hydrogen.
Multiply that by 10 and you get 6.67 moles of Ammonia produced [3 significant figures]