PS 04.1 Development of the Atomic Theory

Who was the philosopher that contributed to the early concept of the atom?

• Aristotle

• Democritus

• Plato

• Socrates

Answer explanation

Democritus was the philosopher who first proposed the idea that matter is composed of small, indivisible particles called atoms, laying the groundwork for atomic theory, unlike Aristotle, Plato, or Socrates.

What are the two theories of matter mentioned in the objectives?

• Continuous and discontinuous

• Solid and liquid

• Atomic and molecular

• Physical and chemical

Answer explanation

The two theories of matter are the continuous theory, which suggests matter can be divided infinitely, and the discontinuous theory, which posits that matter is made up of discrete particles. Thus, the correct answer is continuous and discontinuous.

Which law states that mass is neither created nor destroyed in a chemical reaction?

• Law of definite proportions

• Law of multiple proportions

• Law of conservation of mass

• Law of atomic theory

Answer explanation

The Law of conservation of mass states that in a chemical reaction, mass is neither created nor destroyed. This principle is fundamental in chemistry, ensuring that the total mass of reactants equals the total mass of products.

How many essential points are there in Dalton’s atomic theory according to the objectives?

• Three

• Four

• Five

• Six

Answer explanation

Dalton’s atomic theory consists of five essential points, which include concepts about atoms being indivisible, the nature of compounds, and the conservation of mass. Therefore, the correct answer is five.

What does the continuous theory of matter propose?

• Matter is finite and not limitless.

• Matter is continuous, infinite, and can be divided indefinitely.

• Matter is composed of indivisible particles.

• Matter cannot be divided into smaller pieces.

Answer explanation

The continuous theory of matter suggests that matter is not made of discrete particles but is instead a continuous substance that can be divided infinitely, making the correct choice "Matter is continuous, infinite, and can be divided indefinitely."

According to the discontinuous theory of matter, what is the nature of matter?

• Matter is continuous and infinite.

• Matter is composed of indivisible particles.

• Matter is finite and not limitless.

• Matter can be divided indefinitely.

Answer explanation

According to the discontinuous theory of matter, it posits that matter is finite and not limitless, meaning it is made up of distinct, indivisible particles rather than being continuous or infinitely divisible.

What is an atom?

• A continuous form of matter.

• A finite piece of matter.

• A fundamental, indivisible particle that makes up matter.

• A limitless form of matter.

Answer explanation

An atom is defined as a fundamental, indivisible particle that makes up all matter. This choice accurately describes the basic building blocks of matter, distinguishing them from continuous or limitless forms.

What does the law of definite proportions state?

• Chemical compounds always contain the same proportion of elements by mass, regardless of amount.

• The mass of a reactant must equal the mass of the product for any chemical process.

• The ratios of the masses of the second element that combine with a fixed mass of the first element will be ratios of small whole numbers.

• Elements can form compounds in any proportion.

Answer explanation

The law of definite proportions states that a chemical compound always contains the same proportion of elements by mass, regardless of the amount of the compound. This means the composition is fixed.

What is the law of conservation of mass?

• The mass of a reactant must equal the mass of the product for any chemical process.

• Chemical compounds always contain the same proportion of elements by mass.

• Elements can form compounds in any proportion.

• The ratios of the masses of the second element that combine with a fixed mass of the first element will be ratios of small whole numbers.

Answer explanation

The law of conservation of mass states that in a chemical reaction, the total mass of reactants equals the total mass of products, confirming that mass is neither created nor destroyed.

According to the law of multiple proportions, what happens when two elements form more than one compound?

• The ratios of the masses of the second element that combine with a fixed mass of the first element will be ratios of small whole numbers.

• The mass of a reactant must equal the mass of the product.

• Chemical compounds always contain the same proportion of elements by mass.

• Elements can form compounds in any proportion.

Answer explanation

According to the law of multiple proportions, when two elements form more than one compound, the masses of the second element that combine with a fixed mass of the first will be in ratios of small whole numbers.