Atomic Theory and Law of Definite Proportions

The fact that every sample of a particular chemical compound contains the same elements in exactly the same proportions by mass is known as the law of

• conservation of energy.

• conservation of mass.

• atomic theory.

• definite proportions.

Tags

NGSS.HS-PS1-7

A molecule of carbon monoxide, CO, has one atom of oxygen while a molecule of carbon dioxide, CO₂, has two. In a sample of CO containing 1 g of carbon, 1.33 g of oxygen will combine with the carbon to form the molecule. What is the mass of oxygen in a sample of CO₂ containing 1 g of carbon?

• 1.33g

• 3.0g

• 2.66g

• 0.0g

Tags

NGSS.HS-PS1-7

In 1808, John Dalton established his atomic theory. Which of the following is not part of Dalton’s atomic theory?

• All matter is composed of atoms

• An atom consists of a nucleus and a cloud of electrons.

• Atoms cannot be subdivided, created, or destroyed.

• In chemical reactions, atoms are combined, separated, or rearranged.

Tags

NGSS.HS-PS1-7

Which of the following statements of Dalton’s atomic theory describes conservation of mass?

• All matter is composed of atoms.

• Atoms of a given element are identical in size, mass, and other properties.

• Atoms cannot be subdivided, created, or destroyed.

• Atoms of different chemical elements combine in simple whole-number ratios to form chemical compounds.

Tags

NGSS.MS-PS1-5

Which is one way that Dalton’s atomic theory has been shown to be incorrect?

• Atoms can change identity in chemical reactions.

• Atoms can be split into subatomic particles.

• Atoms can be destroyed by chemical reactions.

• Some atoms of a particular element are identical to atoms of other elements.

Tags

NGSS.HS-PS1-8

The atomic number of an element is

• the mass of the element

• 1 mol of the element

• the number of protons in each atom of the element

• the number of neutrons in each atom of the element

Most of an atom is

• dense

• fluid

• empty

• the nucleus

Which postulate of Dalton's atomic theory can explain the law of definite proportions?

All matter is made of very tiny/small particles called................

• Atomic mass

• Molecules

• Atoms

• Element

Tags

NGSS.MS-PS1-1

Who had established the laws of chemical combination?

• Antoine L. Lavoisier

• John Dalton

• Joseph L. Proust

• Maharishi kanad

Tags

NGSS.HS-PS1-7