Question

the ________ step in balancing a chemical equation is to take inventory or count atoms on the reactant and the product side.
a first
b second
c last
the number 3 next to hydrogen in $nh_3$ is the ____.
a coefficient
b
c

Explanation:

For the first question: Balancing chemical equations starts with identifying and counting atoms on both sides to know which elements need adjustment.
For the second question: A subscript is the small number after an element symbol in a chemical formula, indicating the number of that atom in the molecule; coefficients are whole numbers before formulas, and numerators are unrelated to chemical formula notation.

Answer:

1. A. first
2. C. subscript