Remember: energy is conserved in a chemical reaction (visualize the reaction and question whether heat lies on reactant side (left) or product side (right))
-exothermic- heat is released (heat is on the product side)
>forming an ionic lattice (SALT)- mixture of Na and Cl results in a more stable ionic lattice, causing this reaction to be exothermic
>burning wood
-endothermic- heat is absorbed (heat is on the reactant side)
> cooking an egg
Acid palmitic acid has higher melting point, because it has two more methylene groups.

Acid palmitic acid has higher melting point, because it has two more methylene groups.
Giving it a greater surface area and therefore more intermolecular van der waals interact than the myristic acid.
stearic arid 
linoleic acid
(two double bond)
Stearic acid has higher Melting point, because it does not have any Carbon-Carbon double bonds, whereas linoleic acid has two cis double bonds which prevent the molecules from packing closely together.
Oleic Acid and Linoleic acid.
-one double bond (cis)
Acid palmitic acid has higher melting point, because it has two more methylene groups.
For more such question on methylene group.
brainly.com/question/4279223
#SPJ4
46.6% Oxygen
27.7% Silicon
8.1% Aluminium
5.0% Iron
3.6% Calcium
2.8% Sodium
2.6% Potassium
2.1% Magnesium
The Earth is divided into three chemical layers: the Core [Inner Core (D) and Outer Core (C)], the Mantle (B) and the Crust (A). The Core is predominantly composed of iron and nickel. Even after 4.5 billion years of cooling, the Earth's core remains very hot.
<span>its because they're both structured the same way. for example the sun and the nucleus are the same (in the centre) and the electrons and planets orbiting are the same</span>