Read the following passage. the word "atom" was coined by democritus, who, unlike aristotle, believed that matter can be divided only until we get the smallest "indivisible particle." several years later based on macroscopically observable experimental results, dalton proposed that all matter is composed of atoms. many postulates of atomic theory as proposed by dalton were later rejected by jj thompson, who has to his credit the discovery of sub atomic particles like electrons. use information from the passage to justify whether the characteristics of reliable scientific explanations are present in the development of the atomic theory.

Answer is: the discovery of sub atomic particles like electrons.

J. J. Thomson discovered the electron in 1897.  

His "plum pudding" model (1904) suggested: the electrons are embedded in the positive charge.  

With this model, he abandoned his earlier hypothesis (the atom was composed of immaterial vortices).  

J.J. Thomson placed two oppositely charged electric plates around the cathode ray. He did experiments using different metals as electrode materials and found that the properties of the cathode ray remained constant no matter what cathode material he used.

Tomson concluded that atoms are divisible and that the corpuscles are their building blocks (atoms are made up of smaller particles).  

The correct answer is that yes all the scientific theories and their features contributes to the discovery of an atom.

Explanation:

In the beginning, Democritus gave the term atom, however, he gave the wrong theory regarding atom. The term atom is even used at the present time. Aristotle provided the right theory regarding the prevalence of atom. Then Dalton postulated various things in his atomic theory, in which some were accurate, while others were proved later wrong.  

The accurate postulates of Dalton were also incorporated in J.J. Thomson theory of sub-atomic particles. Thus, all the theories associated with an atom provides to its discovery, irrespective of the fact that whether it is correct or wrong.  

the molecules move in straight line until they collide with each other or with the walls of the container. collisions are perfectly elastic; when two molecules collide, they change their directions and kinetic energies, but the total kinetic energy is conserved.

explanation:

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.