Questions and Answers
Which ancient Greek philosophers argued that matter was composed of small, finite particles called atomos?
Leucippus and Democritus
What did Leucippus and Democritus call the small, finite particles that they believed all matter was composed of?
Atomos
Which Greek philosophers thought of atoms as moving particles that could join together?
Leucippus and Democritus
Who proposed the view that matter consisted of various combinations of the four 'elements'—fire, earth, air, and water?
Signup and view all the answers
Which English schoolteacher revolutionized chemistry with his hypothesis about the behavior of matter being explained using an atomic theory?
Signup and view all the answers
What did John Dalton propose about matter in his atomic theory?
Signup and view all the answers
In Dalton's atomic theory, what is defined as the smallest unit of an element that can undergo a chemical change?
Signup and view all the answers
What did Aristotle and others believe made up the composition of matter?
Signup and view all the answers
How did Leucippus and Democritus describe atoms in their hypothesis?
Signup and view all the answers
What was the term for small, finite particles proposed by Leucippus and Democritus?
Signup and view all the answers
Which ancient Greek philosopher proposed that all matter was composed of small, finite particles called atomos?
Signup and view all the answers
Which ancient Greek philosopher believed that atoms were indivisible and differed in shape and size?
Signup and view all the answers
Which philosopher, in contrast to Leucippus and Democritus, thought that matter was composed of combinations of the four elements?
Signup and view all the answers
Which scientist helped revolutionize chemistry by proposing that the behavior of matter could be explained using an atomic theory?
Signup and view all the answers
What did Aristotle and others believe could be infinitely divided and made up matter?
Signup and view all the answers
In Dalton's atomic theory, what is defined as the smallest unit of an element that can participate in a chemical change?
Signup and view all the answers
Contrary to Aristotle's view, Leucippus and Democritus envisioned atoms as:
Signup and view all the answers
According to Dalton’s atomic theory, why is it impossible to break down an element like copper into simpler substances?
Signup and view all the answers
Which law is demonstrated by the observation that all samples of a pure compound contain the same elements in the same proportion by mass?
Signup and view all the answers
Why does the law of multiple proportions state that when two elements react to form more than one compound, a fixed mass of one element will react with masses of the other element in a ratio of small, whole numbers?
Signup and view all the answers
How is the concept of the law of constant composition related to the law of definite proportions?
Signup and view all the answers
Why do samples that have the same mass ratio not necessarily represent the same substance, as seen with isooctane?
Signup and view all the answers
What does a 2-to-1 ratio, as seen in copper-chlorine compounds, suggest about the atomic composition?
Signup and view all the answers
How does Dalton's atomic theory explain the observation that atoms are neither created nor destroyed during a chemical change?
Signup and view all the answers
Why is it significant to note that different samples of isooctane possess a carbon-to-hydrogen mass ratio of 5.33:1?
Signup and view all the answers
Study Notes
Ancient Greek Philosophers and the Concept of Atoms
- Ancient Greek philosophers Leucippus and Democritus argued that matter was composed of small, finite particles called atomos, derived from the Greek word for “indivisible”.
- These particles differed in shape and size and could join together.
Aristotle's View of Matter
- Aristotle and others believed that matter consisted of various combinations of the four “elements”—fire, earth, air, and water—and could be infinitely divided.
Dalton's Atomic Theory
Postulates of Dalton's Atomic Theory
- Matter is composed of exceedingly small particles called atoms.
- An atom is the smallest unit of an element that can participate in a chemical change.
- An element consists of only one type of atom, which has a mass that is characteristic of the element and is the same for all atoms of that element.
- A macroscopic sample of an element contains an incredibly large number of atoms, all of which have identical chemical properties.
- Atoms of one element differ in properties from atoms of all other elements.
- A compound consists of atoms of two or more elements combined in a small, whole-number ratio.
- In a given compound, the numbers of atoms of each of its elements are always present in the same ratio.
- Atoms are neither created nor destroyed during a chemical change, but are instead rearranged to yield substances that are different from those present before the change.
Dalton's Contributions
- Dalton provided a microscopic explanation of the many macroscopic properties of matter.
- His theory explained the law of conservation of matter, which states that the total mass of matter present when matter changes from one type to another will remain constant.
- Dalton's theory was supported by the experiments of French chemist Joseph Proust, who demonstrated that all samples of a pure compound contain the same elements in the same proportion by mass (law of definite proportions or the law of constant composition).
- Dalton used data from Proust and his own experiments to formulate the law of multiple proportions, which states that when two elements react to form more than one compound, a fixed mass of one element will react with masses of the other element in a ratio of small, whole numbers.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
