KE = 0
<h3>Further explanation </h3>
Energy is the ability to do work
Energy because its motion is expressed as Kinetic energy (KE) which can be formulated as:

So for two objects that have the same speed, the greater the mass of the object, the greater the kinetic energy
The stone in hand is in a motionless state (at rest) so that its velocity (v) = 0, so it has no kinetic energy
But this stone can have <em>potential energy that is gained due to its height</em>
First you need to find the amount of mass of Na2CO3 in one moles
(Use periodic chart)
Na= 22.99 x 2 = 45.98
C = 12.01
O = 16.00 x 4 = 64.00
Add the molar masses together to get 121.99
To find how many grams are in 4 moles, times 121.99 by 4
This gives you 487.96
But the questions asks for the answer to be in kilograms nor grams, to change into kilograms divide by 1000
This gets you the answer: 0.49 kg