50 points! for chemistry. 1.) compare the type of change that occurs when a match is burnt and when a liquid starts boiling. use complete sentences to justify the type of change that occurs. 2.) a glow stick contains a glass vial with chemicals. when the glow stick is bent, the vial breaks and the chemicals react to produce a glow. a science student observes that a glow stick kept in the freezer glows for a longer duration than a glow stick kept at room temperature. what conclusion can be drawn based on the observation? be sure to note the outcome and test variables in the conclusion. 3.) 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. real answers and explanations only, !

The change during the burning of a match stick is a irreversible chemical change while the change when a liquid starts boiling is reversible chemical change.

A change in which the chemistry of compound change is known as the chemical change.

It can be reversible or irreversible.

Reversible change in the chemical compound when some bonds breaks which don't result in chemical composition of compound overall.

As in case of liquid boiling.

Irreversible chemical change is change in chemical composition which can not be reversed at any rate. As the burning of match stick.

The optimum rate of reaction of the glow reaction is at room temperature.

The optimum temperature is equal to room temperature means the reaction will proceed at fastest rate at room temperature and the reaction will early come to its end.

In contrast, in freezer the reaction will proceed at slow rate. Hence it takes more time to finish the reaction in freezer.

So the glow will remain for longer time in freezer.

Yes, all the scientific theories and their characteristics contributes to the discovery of atom.

As in the start, term was given by Democritus. But he gave the wrong theory about atom. But his term is used now. Aristotle give the right theory about the existence of atom.

Dalton presented many postulates in his atomic theory. In which some were correct but other were proved wrong later.

His correct postulates were also included in JJ Thomson theory of sub atomic particles.

Hence all theories related to an object contributes to its discovery whether it is wrong or right.

not clear

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements