Atomic Theories of Ancient Philosophers

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What term did Maharishi Kanad use to describe the smallest particles of matter?

Divisible matter

Atom

Parmanu (correct)

Indivisible particle

Which ancient Greek philosopher proposed that matter could be divided until obtaining indivisible particles?

Pythagoras

Epicurus

Aristotle

Democritus (correct)

What is the significance of the experiments conducted by Lavoisier and L. Proust?

They formulated the law of conservation of mass. (correct)

They defined the smallest particle as an atom.

They discovered the concept of atoms.

They introduced the idea of chemical reactions.

What did Pakudha Katyayama add to the doctrine of indivisible particles?

Particles exist in combined forms to create various matter. Signup and view all the answers

What was the philosophical basis for the early atomic theories proposed by ancient philosophers?

Philosophical considerations Signup and view all the answers

What was the primary focus of ancient Indian and Greek philosophers regarding matter?

The structure and divisibility of matter Signup and view all the answers

In what year range did Maharishi Kanad propose his ideas about particles?

500-400 BC Signup and view all the answers

What is one consequence of the law of conservation of mass in a chemical reaction?

Mass is neither created nor destroyed. Signup and view all the answers

What did Dalton describe as the smallest particles of matter?

Atoms Signup and view all the answers

How do hydrogen and oxygen combine to form water by mass?

1:8 Signup and view all the answers

Which postulate of Dalton's atomic theory explains the law of conservation of mass?

Atoms cannot be created or destroyed. Signup and view all the answers

Which principle relates to Dalton's explanation of the law of definite proportions?

Compounds are formed by fixed ratios of atoms. Signup and view all the answers

What size comparison is used to illustrate how small atoms are?

Smaller than a grain of sand Signup and view all the answers

What was the role of symbols in Dalton's atomic theory?

To identify elements specifically Signup and view all the answers

What is produced when sodium carbonate reacts with ethanoic acid?

Sodium ethanoate Signup and view all the answers

Which of the following best describes why atoms are significant despite their small size?

They are responsible for chemical reactions. Signup and view all the answers

What is the correct formula for magnesium chloride?

MgCl2 Signup and view all the answers

What is the formula for sodium nitrate?

NaNO3 Signup and view all the answers

How does one denote the ratio of polyatomic ions in a chemical formula?

By enclosing the ion in brackets followed by a subscript Signup and view all the answers

What is the simplified formula for calcium oxide?

CaO Signup and view all the answers

What charge do chloride ions carry?

-1 Signup and view all the answers

Which of the following compounds contains the same valency for its constituent elements?

Hydrogen sulphide Signup and view all the answers

What is a binary compound?

A compound made up of two different elements Signup and view all the answers

Which statement about writing chemical formulas is true?

The overall structure must be neutral without showing charges Signup and view all the answers

What is the law of conservation of mass?

Mass cannot be created or destroyed in a chemical reaction. Signup and view all the answers

Who established the two important laws of chemical combination?

Antoine L. Lavoisier Signup and view all the answers

What does the law of definite proportions state?

Compounds have fixed ratios of their constituent elements. Signup and view all the answers

What is a key observation in a chemical reaction according to Dalton's atomic theory?

Atoms are neither created nor destroyed during a reaction. Signup and view all the answers

Why should a cork be placed on the mouth of a flask during a chemical reaction?

To prevent contamination from the air. Signup and view all the answers

What is one of the roles of atomic theory in chemistry?

It provides a foundation for understanding the nature of chemical reactions. Signup and view all the answers

Which scientist is noted for beginning his career as a teacher at the age of twelve?

John Dalton Signup and view all the answers

Which of the following best describes the significance of Lavoisier's contributions to chemistry?

He established the importance of experiments in chemistry. Signup and view all the answers

What is the correct molecular formula for calcium hydroxide?

Ca(OH)2 Signup and view all the answers

How many hydrogen atoms are in one molecule of water (H2O)?

2 Signup and view all the answers

What does the subscript in the formula Ca(OH)2 indicate?

There are two hydroxyl groups. Signup and view all the answers

What is the molecular mass of HNO3?

63 u Signup and view all the answers

Which of the following compounds does not require brackets in its formula?

H2O Signup and view all the answers

What is the molecular mass of water calculated from its atomic masses?

18 u Signup and view all the answers

In the ion PO4^3-, how many total atoms are present?

4 Signup and view all the answers

How does the concept of molecular mass relate to atomic mass?

Molecular mass is the sum of atomic masses of all atoms in a molecule. Signup and view all the answers