Answer:
Density, 
Explanation:
The attached figure shows a 38.6 kg marble slab. The dimensions of the marble slab is 23 cm × 17 cm × 4 cm
Density = mass/volume
Volume of a cuboid shape is equal to, V = 23 cm × 17 cm × 4 cm
V = 1564 cm³
Density,
or
So, the density of the marble slab is 
.
Answer: Activation energy
Explanation:
In a chemical reaction, the reactants contains particles which must collide in order for a reaction to occur. The rate of reaction depends on the frequency of effective collision between the reacting particles. Effective collision are those that result in reactions, which when they occur the colliding particles become activated with increased kinetic energy.
This energy must exceed a particular energy barrier for a particular reaction if the reaction must take place. This energy barrier that must be overcome before a reaction takes place is known as the ACTIVATION ENERGY.
To explain further, when two particles or molecules A and B come in contact with each other, for a reaction to take place, they must collide with a sufficient force to break the bond that exists between them. The minimum combined kinetic energy these reactant particles must possess in order for their collision to result in a reaction is called the activation energy.
