THE COMPONENTS OF MATTER
Refer to the definitions of an element and a compound.
Unlike compounds, elements cannot be broken down by chemical changes into simpler materials.
contain different types of atoms; there is only one type of atom in an element.
1) A compound has constant composition but a mixture has variable composition. 2) A compound has distinctly
different properties than its component elements; the components in a mixture retain their individual properties.
a) The fixed mass ratio means it has constant composition, thus, it is a
b) All the atoms are identical, thus, it is a
c) The composition can vary, thus, this is an
d) The specific arrangement of different atoms means it has constant composition, thus, it is a
Review the definitions of elements, compounds, and mixtures.
a) The presence of more than one element (calcium and chlorine) makes this pure substance a
b) There are only atoms from one element, sulfur, so this pure substance in an
c) The presence of more than one compound makes this a
d) The presence of more than one type of atom means it cannot be an element. The specific, not variable,
arrangement means it is a
a) This scene has 3 atoms of an element, 2 molecules of one compound and 2 molecules of a second compound.
b) This scene has 2 atoms of one element, 2 molecules of a diatomic element and 2 molecules of a compound.
c) This scene has 2 molecules of one element and 3 molecules of a second element.
Restate the three laws in your own words.
a) The law of mass conservation applies to all substances —
elements, compounds, and mixtures
can neither be created nor destroyed, whether it is an element, compound, or mixture.
b) The law of definite composition applies to
only, because it refers to a constant, or definite,
composition of elements within a compound.
c) The law of multiple proportions applies to
only, because it refers to the combination of elements to
Review the three laws:
Law of Mass Conservation, Law of Definite Composition, and Law of Multiple
a) Law of Definite Composition — The compound potassium chloride, KCl, is composed of the same elements
and same fraction by mass, regardless of its source (Chile or Poland).
b) Law of Mass Conservation — The mass of the substance inside the flashbulb did not change during the
chemical reaction (formation of magnesium oxide from magnesium and oxygen).
c) Law of Multiple Proportions — Two elements, O and As, can combine to form two different compounds that
have different proportions of As present.