Chemistry Chapter 3

Front 1

law of conservation of mass

Back 1

mass is neither created nor destroyed during
ordinary chemical or physical reactions

Front 2

law of definite proportions

Back 2

a chemical compound contains the same elements
in exactly the same proportions by mass regardless of the size of the sample or
the source of the compound

Front 3

law of multiple proportions

Back 3

if two or more different compounds are
composed of the same two elements, then the ratio of the masses of the second
element combined with a certain mass of the first element is always a ratio of
small whole numbers

Front 4

atom

Back 4

the smallest unit of an element that maintains the properties of that
element

Front 5

nuclear forces

Back 5

a short-range proton-neutron, proton-proton, or neutron-neutron
force that holds the nuclear particles together

Front 6

atomic mass unit

Back 6

a unit of mass that is exactly 1/12 the mass of a carbon-12
atom, or 1.660 540 × 10–27 kg

Front 7

Avogadro's number

Back 7

6.022 1367 × 1023; the number of particles in exactly one
mole of a pure substance

Front 8

mass number

Back 8

the total number of protons and neutrons in the nucleus of an
isotope

Front 9

mole

Back 9

the amount of a substance that contains as many particles as there are
atoms in exactly 12 g of carbon-12

Front 10

atomic number

Back 10

the number of protons in the nucleus of each atom of an
element

Front 11

isotopes

Back 11

atoms of the same element that have different masses

Front 12

molar mass

Back 12

the mass of one mole of a pure substance

Front 13

nuclide

Back 13

the general term for any isotope of any element; also another term
for an atom that is identified by the number of protons and neutrons in its
nucleus

Front 14

average atomic mass

Back 14

the weighted average of the atomic masses of the
naturally occurring isotopes of an element