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Q1. Maharishi Kanad used the term for matter as
Maharishi Kanad used the term “Padarth” for matter. He was an ancient Indian philosopher who proposed that matter is made up of tiny particles that cannot be divided further. He called these particles “Parmanu” and the matter made from them was called “Padarth”. He believed that the continuous division of matter would eventually lead to the smallest indivisible particles.
Q2. The smallest indivisible particles were named
The smallest indivisible particles were named “Parmanu” by Maharishi Kanad in ancient Indian philosophy. The word “Parmanu” means “that which cannot be divided further.” This concept was similar to the Greek idea of “atomos” (atoms). In modern chemistry, Dalton later used the term “atom” for these indivisible particles.
Q3. Oxygen obtained from 9 g of water is
In water, the mass ratio of hydrogen to oxygen is 1:8. This means that in 9 g of water, 1 g is hydrogen and 8 g is oxygen. This follows the law of constant proportions, which states that a chemical compound always contains the same elements in the same proportion by mass. Water always has 11.11% hydrogen and 88.89% oxygen by mass.
Q4. Scientists needed explanations for
Scientists needed explanations for the laws of chemical combination. As chemistry developed, scientists observed that elements combine in fixed ratios, and mass is conserved in chemical reactions. These observations needed a theoretical explanation, which led to the development of atomic theory. Dalton’s atomic theory was formulated to explain these laws.
Q5. Lavoisier established
Lavoisier established two important laws of chemical combination: the Law of Conservation of Mass and the Law of Definite Proportions. The first law states that mass is neither created nor destroyed in a chemical reaction. The second law states that a compound always contains elements in a fixed proportion by mass. These laws were later explained by Dalton’s atomic theory.
Q6. Ancient philosophers wondered about
Ancient philosophers wondered about the unknown and unseen form of matter. They observed that matter could be divided repeatedly, and they questioned what would happen if division continued indefinitely. This led to the idea that matter must be made of tiny, indivisible particles (atoms) that cannot be seen but form the basis of all matter.
Q7. Experimental validation of atomic ideas was not possible till
Experimental validation of atomic ideas was not possible until the 18th century. In the 18th century, scientists like Lavoisier and Proust established laws of chemical combination through careful experiments. These laws were based on quantitative measurements, which allowed scientists to develop and test atomic theories. Earlier atomic ideas were purely philosophical.
Q8. Combined particles give rise to
Combined particles give rise to various forms of matter. According to atomic theory, different combinations of atoms produce different substances. The way atoms combine determines the properties of the resulting matter. This explains why there are so many different types of substances despite being made from relatively few elements.
Q9. Ancient Indian ideas about atoms were
Ancient Indian ideas about atoms were philosophical. Philosophers like Maharishi Kanad developed ideas about the nature of matter through logical reasoning and philosophical thinking, not through experiments. They did not have the scientific instruments or methods to test their ideas experimentally. Modern atomic theory is based on experimental evidence.
Q10. The law stating fixed mass proportions in compounds is called
The law stating fixed mass proportions in compounds is called the Law of Constant Proportions (also known as the Law of Definite Proportions). This law, established by Joseph Proust, states that a chemical compound always contains the same elements in exactly the same proportion by mass, regardless of its source or method of preparation.
Q11. Dalton used the term
Dalton used the term “atom” for the smallest indivisible particles of matter. He adopted this term from the Greek philosophers, who used the word “atomos” meaning indivisible. Dalton’s atomic theory was based on experimental evidence and laws of chemical combination, unlike earlier philosophical ideas.
Q12. The Indian philosopher who proposed divisibility of matter was
Maharishi Kanad was the Indian philosopher who proposed the divisibility of matter. He lived around 600 BC and suggested that matter could be divided into smaller and smaller particles until an indivisible particle called “Parmanu” was reached. This was similar to the Greek concept of atoms but developed independently.
Q13. Lavoisier’s work marked the beginning of
Lavoisier’s work marked the beginning of modern chemistry. He introduced quantitative measurements in chemistry, established the law of conservation of mass, and identified the role of oxygen in combustion. His work transformed chemistry from a qualitative to a quantitative science, laying the foundation for modern chemical understanding.
Q14. Parmanu refers to particles that
Parmanu refers to particles that cannot be divided further. In ancient Indian philosophy, Maharishi Kanad proposed that matter is made up of tiny particles called “Parmanu,” which were considered to be the smallest, indivisible units of matter. The word “Parmanu” literally means “the smallest particle” or “that which cannot be cut.”
Q15. Dalton’s atomic theory also explained
Dalton’s atomic theory also explained the Law of Definite Proportions (Law of Constant Proportions). According to Dalton, atoms of different elements have different masses, and they combine in fixed ratios to form compounds. This explains why a compound always has the same proportion of elements by mass.
Q16. Greek philosophers suggested matter division will finally produce
Greek philosophers (Democritus and Leucippus) suggested that continuous division of matter will finally produce indivisible particles. They called these particles “atomos,” which means indivisible. They believed that these smallest particles could not be further divided and were the fundamental building blocks of all matter.
Q17. The mass ratio in ammonia is independent of
The mass ratio in ammonia is independent of the method of preparation. This is a consequence of the Law of Constant Proportions. In ammonia (NH₃), nitrogen and hydrogen always combine in a fixed mass ratio of 14:3, regardless of how the ammonia is produced. This ratio does not depend on colour, temperature, or pressure.
Q18. The smallest indivisible particle concept was common to
The smallest indivisible particle concept was common to both Indian and Greek philosophers. Maharishi Kanad in India and Democritus in Greece independently proposed that matter is made up of tiny, indivisible particles. The Indian philosophers called them “Parmanu” and the Greek philosophers called them “atomos.” Both cultures developed similar ideas around the same time.
Q19. The laws established by Lavoisier are related to
The laws established by Lavoisier are related to chemical combination. He established the Law of Conservation of Mass and the Law of Definite Proportions, which describe how elements combine to form compounds. These laws were crucial in understanding the nature of chemical reactions and laid the foundation for modern chemistry.
Q20. If 9 g of water is decomposed, hydrogen obtained is
If 9 g of water is decomposed, the hydrogen obtained is 1 g. In water, the mass ratio of hydrogen to oxygen is 1:8. So in 9 g of water, there is 1 g of hydrogen and 8 g of oxygen. This follows the Law of Constant Proportions, which states that water always contains hydrogen and oxygen in the same proportion by mass.
Q21. By the end of the eighteenth century, scientists recognized the difference between
By the end of the eighteenth century, scientists recognized the difference between elements and compounds. Lavoisier’s work helped clarify that elements are substances that cannot be broken down further, while compounds are made of two or more elements chemically combined. This distinction was essential for the development of atomic theory.
Q22. In ammonia, nitrogen and hydrogen are present in the mass ratio
In ammonia (NH₃), nitrogen and hydrogen are present in the mass ratio of 14:3. This means that for every 14 parts by mass of nitrogen, there are 3 parts by mass of hydrogen. The atomic masses are N=14 and H=1, and there are three hydrogen atoms for each nitrogen atom in ammonia, giving a mass ratio of 14:3.
Q23. The law of definite proportions was stated by
The Law of Definite Proportions was stated by Joseph Proust, a French chemist. He proposed that a chemical compound always contains the same elements in the same proportion by mass, regardless of its source or method of preparation. This law was one of the key observations that Dalton’s atomic theory aimed to explain.
Q24. According to Maharishi Kanad, continuous division of matter leads to
According to Maharishi Kanad, continuous division of matter leads to the smallest particles, which he called “Parmanu.” He believed that if you keep dividing matter, you would eventually reach particles that could not be divided further. These indivisible particles were the fundamental building blocks of all matter.
Q25. Many compounds are composed of
Many compounds are composed of two or more elements. Compounds are formed when atoms of different elements combine chemically in fixed proportions. Examples include water (hydrogen and oxygen), salt (sodium and chlorine), and ammonia (nitrogen and hydrogen). A substance made of only one element is not a compound.
Q26. The word ‘atom’ was taken by Dalton from
The word ‘atom’ was taken by Dalton from the Greeks. The Greek philosophers Democritus and Leucippus used the word “atomos,” meaning indivisible. Dalton adopted this term for his atomic theory. The Greeks had developed the concept of atoms through philosophical reasoning, and Dalton used the word to describe his experimentally-supported theory.
Q27. The idea of divisibility of matter in India dates back to around
The idea of divisibility of matter in India dates back to around 500 BC. Maharishi Kanad, who lived around this time, proposed that matter is made up of tiny particles called “Parmanu.” His ideas were philosophical and based on logical reasoning, similar to the Greek philosophers of the same era.
Q28. The word atom means
The word atom comes from the Greek word “atomos,” which means indivisible. This reflects the ancient belief that atoms are the smallest particles of matter that cannot be further divided. In modern science, we now know that atoms can be further divided into protons, neutrons, and electrons, but the name remains.
Q29. Law of constant proportions is also known as
The Law of Constant Proportions is also known as the Law of Definite Proportions. Both names refer to the same principle: that a chemical compound always contains the same elements in the same proportion by mass, regardless of its source or method of preparation. This law was established by Joseph Proust.
Q30. The mass ratio of hydrogen to oxygen in water is
The mass ratio of hydrogen to oxygen in water (H₂O) is 1:8. This means that for every 1 gram of hydrogen, there are 8 grams of oxygen in water. The atomic masses are H=1 and O=16, and there are two hydrogen atoms for each oxygen atom, giving a mass ratio of 2:16 = 1:8.
Q31. Which philosopher elaborated Kanad’s doctrine?
Pakudha Katyayama elaborated Kanad’s doctrine. He was an ancient Indian philosopher who further developed the atomic ideas proposed by Maharishi Kanad. He suggested that atoms normally exist in a combined form, giving rise to various forms of matter. His work was part of the Vaisheshika school of philosophy.
Q32. In a compound, elements are present in
In a compound, elements are present in the same proportions by mass. This is the Law of Constant Proportions (or Definite Proportions). A compound always contains its constituent elements in a fixed ratio. For example, water always has 1 part hydrogen and 8 parts oxygen by mass, regardless of the source of water.
Q33. Greek philosophers who proposed indivisible particles were
The Greek philosophers Democritus and Leucippus proposed the concept of indivisible particles (atomos). They suggested that matter is made up of tiny, indivisible particles that cannot be further divided. This idea was purely philosophical and not based on experiments. Socrates, Plato, and Aristotle had different views on the nature of matter.
Q34. Scientists became interested in
Scientists became interested in how elements combine to form compounds. This led to the study of chemical combination and the formulation of laws like the Law of Conservation of Mass and the Law of Constant Proportions. Understanding how elements combine was essential for the development of atomic theory.
Q35. Dalton’s theory was based on
Dalton’s theory was based on the laws of chemical combination. He observed that elements combine in fixed ratios (Law of Constant Proportions) and that mass is conserved in chemical reactions (Law of Conservation of Mass). He proposed his atomic theory to explain these laws. His theory provided a scientific explanation for these observations.
Q36. Dalton provided the basic theory about
Dalton provided the basic theory about the nature of matter. His atomic theory proposed that all matter is made up of tiny particles called atoms, which are indivisible and indestructible. This theory explained the laws of chemical combination and provided a scientific basis for understanding the composition and behaviour of matter.
Q37. During a chemical reaction, mass
During a chemical reaction, mass remains unchanged. This is the Law of Conservation of Mass, which states that mass is neither created nor destroyed in a chemical reaction. The total mass of the reactants equals the total mass of the products. This law was established by Lavoisier and is a fundamental principle of chemistry.
Q38. According to Proust, elements in a compound are present
According to Proust, elements in a compound are present in definite proportions by mass. This is the Law of Definite Proportions (or Constant Proportions). Proust’s experiments showed that a compound always contains the same elements in the same proportion by mass, regardless of how it is prepared.
Q39. Democritus named indivisible particles as
Democritus named indivisible particles as “atoms” (from the Greek word “atomos” meaning indivisible). He and his teacher Leucippus proposed that all matter is composed of these tiny, indivisible particles. The Indian philosopher Maharishi Kanad independently called these particles “Parmanu.”
Q40. The law stating mass is neither created nor destroyed is called
The law stating that mass is neither created nor destroyed in a chemical reaction is called the Law of Conservation of Mass. This law was established by Antoine Lavoisier. It states that the total mass of the products in a chemical reaction equals the total mass of the reactants. This is one of the fundamental laws of chemistry.
Q41. According to Pakudha Katyayama, particles normally exist in
According to Pakudha Katyayama, particles normally exist in a combined form. He elaborated on the atomic ideas of Kanad, suggesting that atoms are not usually isolated but combine to form various substances. This view recognized that the combination of particles gives rise to the different forms of matter we observe around us.
Q42. According to Dalton, the smallest particles of matter are
According to Dalton, the smallest particles of matter are atoms. He proposed that atoms are indivisible, indestructible particles that make up all matter. Atoms of different elements have different masses and properties, and they combine in fixed ratios to form compounds. Dalton’s atomic theory was the first scientific theory of the nature of matter.
Q43. Early ideas about atoms were based on
Early ideas about atoms were based on philosophical considerations. Ancient philosophers in India and Greece developed atomic ideas through logical reasoning and philosophical thinking, not through experiments. They did not have the instruments to test their ideas scientifically. It was much later that experimental evidence supported these early ideas.
Q44. Greek philosophers proposed atomic ideas during
Greek philosophers proposed atomic ideas during the same era as Indian philosophers (around 500-600 BC). Democritus in Greece and Maharishi Kanad in India developed similar ideas about the nature of matter independently. This shows that philosophical thinking about the nature of matter was happening in different parts of the world at roughly the same time.
Q45. Law of conservation of mass applies to
The Law of Conservation of Mass applies to chemical reactions. It states that in a closed system, mass is conserved during a chemical reaction. It does not apply to nuclear reactions (where mass is converted to energy) or to motion. While it also applies to physical changes, its primary importance is in understanding chemical reactions.
Q46. The British chemist who explained these laws was
The British chemist who explained the laws of chemical combination was John Dalton. He developed the atomic theory to provide a scientific explanation for the Law of Conservation of Mass and the Law of Constant Proportions. Dalton’s atomic theory was the first comprehensive theory of the nature of matter.
Q47. Which scientist worked along with Lavoisier on laws of chemical combination?
Joseph Proust worked along with Lavoisier on the laws of chemical combination. Proust established the Law of Definite Proportions (Constant Proportions), while Lavoisier established the Law of Conservation of Mass. Both laws were important contributions to understanding chemical combination and were later explained by Dalton’s atomic theory.
Q48. Antoine L. Lavoisier laid the foundation of
Antoine Lavoisier laid the foundation of chemical sciences. He introduced quantitative methods in chemistry, established the Law of Conservation of Mass, and helped identify and name many elements. His work transformed chemistry from a descriptive to a quantitative science and marked the beginning of modern chemistry.
Q49. Dalton adopted the idea of
Dalton adopted the idea of divisibility of matter from earlier philosophers. He built upon the ancient concept that matter is made up of tiny particles. However, unlike the purely philosophical ideas of the ancients, Dalton’s theory was based on experimental evidence and the laws of chemical combination.
Q50. Dalton’s atomic theory explained
Dalton’s atomic theory explained the conservation of mass. According to his theory, atoms are indivisible and indestructible, so they cannot be created or destroyed in a chemical reaction. This explains why mass is conserved during a chemical reaction. The theory also explained the Law of Constant Proportions and the Law of Multiple Proportions.