Chapter 2

Question 1

Who described the material world as atomos?

Answer 1

Democritus and other Greek philosophers

Question 2

atomos means

Answer 2

indivisible or uncuttable

Question 3

John Dalton is known for what?

Answer 3

coming up with an atomic theory that linked elements with atoms

Question 4

Dalton’s theory explained laws of what?

Answer 4

chemical combination

Question 5

explain the law of constant composition

Answer 5

in a given compound, relative numbers and kinds of atoms are constant

Question 6

explain the law of conservation of mass

Answer 6

total mass of materials present after a chemical reaction is the same as the total mass present before the reaction

Question 7

the law of multiple proportions states that If two __________ A and B combine to form more than one ____________, the masses of B that can combine with a given mass of A are in the _________ of small whole numbers

Answer 7

elements, compound, ratio

Question 8

what is the first postulate in dalton’s atomic theory

Answer 8

each element is composed of atoms

Question 9

The second postulate in Dalton’s theory states that all atoms of a given element are _______, but the atoms of one element are _________ from the atoms of all other elements.

Answer 9

identical, different

Question 10

what is the third postulate in dalton’s atomic theory

Answer 10

Atoms of one element cannot be changed into atoms of a different element by chemical reactions; atoms are neither created nor destroyed in chemical reactions.

Question 11

The fourth postulate in dalton’s atomic theory states that compounds are formed when _______ of more than one ________ combine; a given __________ always has the ________ relative number and kind of atoms

Answer 11

Atoms, element, compound, same

Question 12

An example that shows the law of multiple proportions: water contains _ g of oxygen combined with _ g of hydrogen. hydrogen peroxide has ___ g of oxygen combined with ____ g of hydrogen. ratio of the masses of oxygen per gram of hydrogen in the two compounds is _:1

Answer 12

8, 1, 16, 1, 2

Question 13

what is a proton’s atomic mass unit

Answer 13

1.0073

Question 14

what is a neutron’s atomic mass unit

Answer 14

1.0087

Question 15

what is an electron’s atomic mass unit

Answer 15

5.486*10^-4

Question 16

1 atomic mass unit equals what?

Answer 16

1.66054*10^-24

Question 17

The law of conservation of mass states that the total _______ of substances present at the end of a ______ process is the ________ as the mass of substances present ______ the process took place

Answer 17

mass, chemical, same, before

Question 18

The law of constant composition states that in a given compound, the relative ________ and kinds of __________ are _______

Answer 18

numbers, atoms, constant

Question 19

The law of multiple proportions states that if two elements, A and B, form more than one __________, the ___________ of B that combine with a given ______ of A are in the ________ of small whole numbers

Answer 19

compound, masses, mass, ratio

Question 20

isotopes are atoms of the ______ element with _________ masses

Answer 20

same, different

Question 21

isotopes have different numbers of _______, but the same number of ___________

Answer 21

neutrons, protons