Lesson 4.2

Question 1

In ancient Greek philosophy, the concept of “nothing comes from nothing” is an important idea.

During the 18th century, Aristotle’s adaptation of the concept of the four elements of matter is still dominant.

Question 2

introduced the concept of phlogiston

Answer 2

German scientist, Georg Ernst Stahl

Question 3

a universal component of fire that came from a Greek word for inflammable

Every combustible substance contained a specific amount of

Answer 3

Phlogiston

Question 4

According to this theory, metal calx, when heated with charcoal, produces metal. In this reaction, he explained that the phlogiston of charcoal had united with calx. Therefore, metals are also combustibles.

Question 5

made the first breakthrough in the study of chemical reaction.

(Late 18th century)

Answer 5

a French chemist, Antoine Lavoisier

Question 6

Due to his curiosity about the study of combustion and the concept of phlogiston, he first tried to burn phosphorus and sulfur. In his experiment, both gained weight which resulted in both elements gaining weight.

Lavoisier later on concluded that combustion involves the reaction of a metal or an organic substance to a “common air.”

Question 7

Antoine Lavoisier named this “common air” as

Answer 7

oxygène (oxygen)

Question 8

In June 1783, Lavoisier reacted oxygen with inflammable air, obtaining “water in a very pure state.”

He concluded that water was not an element but a compound of oxygen and inflammable air or _ as it is known.

Answer 8

Hydrogen

Question 9

He also decomposed water into oxygen and hydrogen. Both reactions gained the same weight.

Lavoisier, explained the phenomenon in his famous textbook, Trait lmentaire de Chimie, that “… in every operation, an equal quantity of matter exists both before and after the operation.” This concept was also known as

Answer 9

the law of conservation of mass

Question 10

States that matter can be neither created or destroyed

Answer 10

the law of conservation of mass

Question 11

revolves to the idea that the total mass of the reactants is the same as the total mass of the products

Answer 11

law of conservation of mass

Question 12

a french chemist proposed the law of constant composition

Answer 12

Joseph Proust

Question 13

if a pure compound is broken down into its constituent elements, the masses of the constituents will always have the same proportions, regardless of the quantity or source of the original substance

Answer 13

law of constant composition

Question 14

studied gases and gaseous mixtures under different external conditions.

Building on Proust’s work, he noted that mathematically discrete manner in which elements combined to form different compounds.

Answer 14

John Dalton

Question 15

which states that when two elements form a series of compounds, the masses of one that combine with a fixed mass of the other are in the ratio of (small) integers to each other.

Answer 15

law of multiple proportions

Question 16

Source of Dalton’s Atomic Theory Postulate 1

Elements are composed of extremely small particles, called atoms.

Answer 16

Democritus Idea of an atom

An atom is an indestructible and indivisible particle.

Question 17

Source of Dalton’s Atomic Theory Postulate 3

Compounds are composed of atoms of more than one element. In any compound, the ratio of the numbers of atoms of any two of the elements present is either an integer or a simple fraction.

Answer 17

Law of Constant Proportion

If a compound is broken down into its constituent elements, the masses of the constituents will always have the same proportions, regardless of the quantity or source of the original substance.

Law of Multiple Proportion

When two elements form a series of compounds, the masses of one that combine with a fixed mass of the other are in the ratio of (small) integers to each other.

Question 18

Source of Dalton’s Atomic Theory Postulate 4

A chemical reaction involves only the separation, combination, or rearrangement of atoms; it does not result in their creation or destruction.

Answer 18

Law of Conservation of Mass

Matter can be neither created nor destroyed.