Answer: Rate of decomposition of acetaldehyde in a solution is 
Explanation:
Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.
For a reaction : 
![Rate=k[A]^x](https://tex.z-dn.net/?f=Rate%3Dk%5BA%5D%5Ex)
k= rate constant
x = order of the reaction = 2


Thus rate of decomposition of acetaldehyde in a solution is
Data:
F (force) = 22.0 N
m (mass) = ? (in Kg)
a (acceleration) = 5.5 m/s²
We apply the data to the Resultant Force formula, we have:
4.0 kg
I hope this helps. =)