Which of the following is a property of a pure substance? it has distinct properties that are uniform. its components can be separated with ease. it is made up of two or more types of compounds. the original components retain their individual properties.

The original components retain their individual properties.

Explanation:

A pure substance has a consistent property. A pure substance can be an element, a compound.

Example: Diamond, tin, gold etc are pure elements

carbon dioxide, sugar, salt are pure compounds.

Sometimes homogeneous mixtures are also considered to be pure substance.

In all of theme we cannot separate the components easily.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.

fe 55.85 g/mol and h2o 18.02 g/mol.