So the empirical formula is Mg3N2
The answer is, All of the above
Im not sure but it could be 4 (H)

Here's the balanced equation for given Double displacement reaction ~

The products fored are : Lead Iodide ( PbI2 ) and Potassium Nitrate ( KNO3 )
Acceleration can be described as changes in speed, changes in direction, or changes in both. Acceleration is a vector.