In a lab report, students must write out the word equation for Zn + Pb(NO3)2 – Zn(NO3)2 + Pb. What is the correct word equation?

The answer is D, 2 moles of nitrogen, 8 moles of hydrogen, 1 mole of sulfur.

Explanation: We can figure out the moles in this chemical equation by observing the subscripts. Nitrogen does not have a subscript, but outside the ion it is included in has one, so the amount of nitrogen moles is 2 (1 x 2 = 2). There are 4 moles of hydrogen, and also a subscript of 2 outside the ion hydrogen is included in, we must multiply 4 by 2 to get 8 moles of hydrogen. Sulfur has no subscript, so it only has one mole.