Atomic Theory and Law of Definite Proportions

John Dalton thought that atoms

• contain molecules.

• cannot be broken down further.

• are all composed of carbon.

• have no mass.

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.

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 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.

• multiple proportions.

• definite proportions.

Tags

NGSS.HS-PS1-7

In an experiment, Alex and Rachel discover that their sample of table salt, also known as sodium chloride, NaCl, consists of 39.34% by mass sodium, Na, and 60.66 % by mass chlorine, Cl. Later, Alex wonders what the percentage of Na might be in the table salt in his saltshaker at home. Rachel tells him, correctly, that it is

• 39.34%

• 60.66%

• 90%

• impossible to tell without analyzing the salt.

Tags

NGSS.MS-PS1-1

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

The elements oxygen and hydrogen react chemically to form water. How much water would form if 16 grams of hydrogen reacted with 34 grams of oxygen?

• 50 g

• 60 g

• 40 g

• 18 g

Tags

NGSS.HS-PS1-7

True or False: Atoms can be subdivided into smaller particles.

• True

• False

Tags

NGSS.HS-PS1-8

Which of the following statements of Dalton's atomic theory describes the law of conservations 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.HS-PS1-7

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

• Atoms can change identity in chemical reactions.

• Atoms can 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-PS1-7