Question 1

How many years ago was an atomic view of matter was first proposed?

Accepted Answer

The atomic view of matter was first proposed by ancient Greek philosophers like Democritus around 2500 years ago.

Question 2

32 g of sulfur will react with 48 g of oxygen to produce 80 g of sulfur trioxide.If 16 g of sulfur and 100 g of oxygen are placed into a sealed container and allowed to react,what is the mass of the material in the container after the reaction is completed?

Accepted Answer

According to the given information, the ratio of sulfur to oxygen for the production of sulfur trioxide is 32 g: 48 g or 2:3. Therefore, for 16 g of sulfur, we need (16 g x 3)/2 = 24 g of oxygen. This means that the 100 g of oxygen present is in excess, so all of the sulfur will react with 24 g of oxygen to produce 40 g of sulfur trioxide (16 g sulfur + 24 g oxygen = 40 g sulfur trioxide). Therefore, the mass of the material in the container after the reaction is completed is 40 g (16 g of unreacted sulfur + 24 g of unreacted oxygen + 40 g of sulfur trioxide).

Question 3

Hydrogen peroxide decomposes into water and oxygen when exposed to heat or light.A tightly capped bottle of hydrogen peroxide is placed on a mass scale (a balance)and exposed to light for three weeks.The mass reading on the scale does not change.This is an example of

Accepted Answer

The Law of Conservation of Mass states that in a chemical reaction, matter cannot be created or destroyed, only rearranged. In this case, even though hydrogen peroxide is decomposing into water and oxygen, the total mass remains the same, indicating that no matter has been lost or gained.

Question 4

By definition,which of the following can be broken down into simpler substances?

Accepted Answer

A compound is a substance made up of two or more different elements chemically bonded together. It can be broken down into simpler substances through chemical reactions.

B) atom and ion cannot be broken down into simpler substances as they are already the smallest unit of matter.

C) solid and D) liquid are states of matter and cannot be broken down into simpler substances.

Question 5

Approximately how many elements occur naturally on Earth?

Accepted Answer

As of 2021, there are 90 naturally occurring elements on Earth. These elements range from hydrogen, the lightest element, to uranium, the heaviest naturally occurring element.

Question 6

A student measures 10.5 g of mercury(II)oxide into an open test tube and heats the tube.The heat causes the mercury(II)oxide to decompose into mercury and oxygen.After reaction,the student finds the mass of the contents of the tube to be 9.7 g.Which one of the following describes these observations?

Accepted Answer

According to the Law of Conservation of Mass, the total mass of the reactants and products in a chemical reaction should be the same. However, in this case, the mass of the products (mercury and oxygen) is less than the mass of the reactant (mercury(II)oxide). This can only be explained if some of the oxygen gas has escaped from the open test tube during the reaction. Therefore, option B is the best choice.

Question 7

Which of the following statements about atoms is NOT true?

Accepted Answer

Scientists have indeed synthesized atoms through various nuclear reactions involving particle accelerators and other techniques.

Question 8

A mixture containing 50 grams of carbon and 75 grams of oxygen is sealed in a flask.The total mass of the system is 225 grams.The flask is heated to cause the carbon and oxygen to react.The sealed flask is massed.What is the mass of the sealed flask?

Accepted Answer

The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction. Therefore, the mass of the sealed flask remains 225 grams.

Question 9

Lavoisier performed many of the same experiments as his predecessors.The one thing that most distinguished Lavoisier's work was

Accepted Answer

Lavoisier's most distinguishing feature was his accurate mass measurements, which allowed him to develop the law of conservation of mass. This law states that mass is neither created nor destroyed during a chemical reaction, but rather is conserved. This was a major shift from the prevalent belief in phlogiston theory, which held that substances lost weight during combustion.

Question 10

Lavoisier measured the mass of substances before and after chemical reactions and summarized his observations in a(n)

Accepted Answer

Lavoisier observed the law of conservation of mass, which states that the mass of a closed system (in this case, the reactants and products of a chemical reaction) remains constant over time. He summarized this observation in what is now known as Lavoisier's Law or the Law of Conservation of Mass. Therefore, the best choice is D, law.

Question 11

Which one of the following statements is NOT a correct statement of the Law of Conservation of Mass?

Accepted Answer

The Law of Conservation of Mass states that the mass of a system is conserved in a chemical reaction and that matter cannot be created or destroyed. It also states that atoms are conserved in chemical reactions. Statement A is incorrect because the mass of a system is not dependent upon chemical reactions that may occur, but rather it is a constant value that remains unchanged throughout the reaction.

Question 12

The amount of aluminum on the earth today relative to the amount 100 years ago when Al was first commercially extracted from bauxite,an aluminum containing ore,

Accepted Answer

The total amount of aluminum on Earth remains essentially the same because it is not being lost from the planet; it is simply being extracted and recycled.

Question 13

The amount of carbon on the earth,including the atmosphere,

Accepted Answer

The amount of carbon on Earth, including the atmosphere, is essentially constant due to the carbon cycle, which involves movement of carbon between different reservoirs, such as the atmosphere, oceans, and land. While human activities such as burning fossil fuels can temporarily increase the amount of carbon in the atmosphere, natural processes such as photosynthesis and respiration help maintain a relatively stable amount of carbon on Earth over long periods of time.

Question 14

The "father of modern chemistry" is

Accepted Answer

Antoine Lavoisier is commonly referred to as the "father of modern chemistry" due to his pioneering work in the development of the scientific method in chemistry and his discovery of the law of conservation of mass.

Question 15

The ancient Greeks believed that matter was composed of four basic elements.Which one of the following was NOT one of the four?

Accepted Answer

Mercury was not considered one of the four basic elements by the ancient Greeks. The four elements were earth, water, air, and fire.

Question 16

Leucippus and Democritus believed that all of the following statements about matter were true EXCEPT

Accepted Answer

Leucippus and Democritus believed that matter was made up of atoms, that each type of matter had a distinctive size and shape, and that substances are mixtures of different kinds of atoms. However, they did not believe that matter was continuous. Instead, they believed that there was empty space between atoms.

Question 17

32 g of sulfur will react with 48 g of oxygen to produce 80 g of sulfur trioxide.If 16 g of sulfur and 100 g of oxygen are placed into a sealed container and allowed to react,what is the mass of sulfur trioxide in the container after the reaction is completed?

Accepted Answer

The reaction is limited by the amount of sulfur. 16 g of sulfur will react with 24 g of oxygen (half of 48 g needed for 32 g of sulfur) to produce 40 g of sulfur trioxide.

Question 18

Leucippus and Democritus proposed the "first" atomic view of matter.They arrived at this view based on

Accepted Answer

Leucippus and Democritus developed their atomic theory based on philosophical and intuitive speculation, rather than empirical experimentation or measurements. They believed that matter was made up of tiny, indivisible particles called atoms, which differed in size, shape, and arrangement to create different substances. While their ideas were influential, it wasn't until centuries later that the atomic theory was supported by scientific evidence and refined with experiments and measurements.

Question 19

Which philosopher believed that matter was continuous and was not made up of atoms?

Accepted Answer

Aristotle believed that matter was continuous and not made up of individual particles or atoms, which was later challenged by the atomic theory proposed by Dalton and other scientists. Democritus was actually one of the first philosophers to propose the idea of atoms, while Lavoisier focused more on the study of chemical reactions and the conservation of mass.

Question 20

The Greek word atomos means

Accepted Answer

The Greek word atomos means "uncuttable," which is the best fit for the concept of atoms being indivisible and unbreakable.

Quiz 2: Atoms