CHEM 103 EXAM 1 2026
ALL QUESTIONS AND
ANSWERS
Mass - ANSWER ---Mass is a measure of the amount of matter in an object.
-Mass is independent of the location of an object.
-An object on the earth has the same mass as the same object on the moon, but
not same weight.
Weight - ANSWER ---Weight is a measure of gravitational force acting on
object.
-Weight depends on the location of an object.
-Force = Mass * Acceleration, F = ma, Wt = m(gravity).
-An object weighing 1.0 lb on earth, weighs about 0.17 lb on the moon. Mass of
object is constant. Moon has 1/6 gravity of earth, which reduces apparent weight
of object.
What is chemistry? - ANSWER --Chemistry is the study of the physical and
compositional changes of matter.
,Chemistry is called the Central Science.
Many health related areas of study are based on Chemistry.
Matter - ANSWER --Matter is anything that has mass, occupies space and is
made-up of atoms or parts of atoms.
Physical Properties of Matter - ANSWER ---Physical properties can be
observed or measured without changing the composition of the matter being
observed.
Examples of physical properties are: color, shape and mass, and all changes of
state like gas to a liquid.
Chemical Properties of Matter - ANSWER ---Chemical properties can be
observed or measured only when the composition of matter is changed.
Examples of chemical properties are flammability and the ability to react (e.g.
when vinegar and baking soda are mixed). Atoms must change partners.
Physical changes of Matter - ANSWER ---Physical changes are reversible.
-Physical changes take place without a change in composition. Atoms are not
changing partners.
-Nothing new is being created.
, Examples of physical changes are freezing, melting, or evaporation of a substance
(e.g. water). H2O(s) → H2O(l), ice → water.
Separation of compounds is a physical change.
ex/ separating iron filing from sand is a chemical reaction
Chemical View of the Atom - ANSWER ---Nucleus is the center containing
protons (+) and neutrons (o). Electrons (-) are on the outside.
-Atomic number = number of protons, which defines element.
-Atomic mass = mass of protons and mass of neutrons.
-Number of electrons = number of protons in neutral atom.
-Neutron mass = proton + electron.
Elements - ANSWER ---Elements are pure substances made up of
homoatomic molecules or individual atoms of the same kind.
Examples are oxygen gas made up of homoatomic molecules, O2, and copper
metal made up of individual copper atoms.
Compounds - ANSWER ---Compounds are pure substances that are made up
of atoms bonded to form heteroatomic molecules or individual (ions) of two or
more different kinds of atoms.
ALL QUESTIONS AND
ANSWERS
Mass - ANSWER ---Mass is a measure of the amount of matter in an object.
-Mass is independent of the location of an object.
-An object on the earth has the same mass as the same object on the moon, but
not same weight.
Weight - ANSWER ---Weight is a measure of gravitational force acting on
object.
-Weight depends on the location of an object.
-Force = Mass * Acceleration, F = ma, Wt = m(gravity).
-An object weighing 1.0 lb on earth, weighs about 0.17 lb on the moon. Mass of
object is constant. Moon has 1/6 gravity of earth, which reduces apparent weight
of object.
What is chemistry? - ANSWER --Chemistry is the study of the physical and
compositional changes of matter.
,Chemistry is called the Central Science.
Many health related areas of study are based on Chemistry.
Matter - ANSWER --Matter is anything that has mass, occupies space and is
made-up of atoms or parts of atoms.
Physical Properties of Matter - ANSWER ---Physical properties can be
observed or measured without changing the composition of the matter being
observed.
Examples of physical properties are: color, shape and mass, and all changes of
state like gas to a liquid.
Chemical Properties of Matter - ANSWER ---Chemical properties can be
observed or measured only when the composition of matter is changed.
Examples of chemical properties are flammability and the ability to react (e.g.
when vinegar and baking soda are mixed). Atoms must change partners.
Physical changes of Matter - ANSWER ---Physical changes are reversible.
-Physical changes take place without a change in composition. Atoms are not
changing partners.
-Nothing new is being created.
, Examples of physical changes are freezing, melting, or evaporation of a substance
(e.g. water). H2O(s) → H2O(l), ice → water.
Separation of compounds is a physical change.
ex/ separating iron filing from sand is a chemical reaction
Chemical View of the Atom - ANSWER ---Nucleus is the center containing
protons (+) and neutrons (o). Electrons (-) are on the outside.
-Atomic number = number of protons, which defines element.
-Atomic mass = mass of protons and mass of neutrons.
-Number of electrons = number of protons in neutral atom.
-Neutron mass = proton + electron.
Elements - ANSWER ---Elements are pure substances made up of
homoatomic molecules or individual atoms of the same kind.
Examples are oxygen gas made up of homoatomic molecules, O2, and copper
metal made up of individual copper atoms.
Compounds - ANSWER ---Compounds are pure substances that are made up
of atoms bonded to form heteroatomic molecules or individual (ions) of two or
more different kinds of atoms.
