CHEM1011 Study Notes
ATOMIC STRUCTURE
• The atom is composed of a nucleus and a surrounding electron cloud
• The nucleus contains protons and neutrons and is orbited by the
electrons
• Atoms are neutral in nature but can gain or lose electrons to become
charged ions
• An ion can be either a cation (+) or an anion (-)
• An atom can also share its electrons with other atoms to form a covalent
bond
• An element is defined by its number of protons
• An isotope of an element has differing amounts of neutrons to affect its
molecular mass
• Each element has been categorized into the Periodic Table of Elements
NOMENCLATURE
• For ionic compounds, the cation is named before the anion and altered
suffix.
• Carbon compounds are named using a prefix and suffix determined by
the number of carbon atoms and the nature of intermolecular bonds
respectively
• For inorganic compounds, the central atom is named first before the
numbered prefix and the name of the other atoms
MOLES
• A mole of a substance is the amount of atoms found in 1g of a carbon-12
atom
• A mole is defined as approximately 6.02e23 atoms
• The molar mass of an element is the mass of 1 mole
• Molarity is the concentration of a solute in a solution
• Atoms combine in ratios of equal molar ratios as expressed in chemical
equations
CHEMICAL DEFINITIONS
• A compound is two or more elements chemically bonded together
• A molecule is two or more atoms of any kind that are chemically bonded
• The empirical formula is the simplest ratio of elemental combinations
• The molecular formula is the ratio of elemental combinations as found in
nature
MEASURING PRESSURE
Pressure can be measured using various devices:
• Barometer – a closed tube filled with liquid mercury used to measure
atmospheric pressure
• Manometer – a double sided tube with one end open to the atmosphere
and another to a pressure measured gas
, GAS LAWS
• Boyle’s Law shows that in an enclosed gas, volume is inversely
proportional to pressure and volume multiplied by pressure is constant
for each system
• Charles’ Law demonstrates that the volume of a gas is proportional to
its temperature
• Avogadro’s Law states that the amount of a gas is proportional to its
volume
• In combining these various laws we derive the Ideal Gas Law which
shows that PV = nRT
• The Law of Partial Pressures states that the sum of the pressures of each
individual gas is equal to the pressure of the overall system
MOLECULAR THEORY OF GASES
• Gases are composed of molecules of negligible size compared to their
overall volume
• Molecules move randomly at various speeds and their collisions are
perfectly elastic
• Average kinetic energy is proportional to temperature
• Pressure originates from the force created when molecules collide with a
surface or each other
• Average velocity of gas molecules: sqrt(3*R*T/(Molar Mass))
• Effusion is the escape of gases through a miniscule hole, whereas
diffusion is the mixing of various gases until the mixture is homogeneous
• Graham’s Law states that the rate of effusion and diffusion of two gases
(at equal pressure and temperature) is inversely proportional to the
square roots of their molecular masses
PROPERTIES OF LIGHT
• Has properties of refraction, diffraction and interference
• Light is used as a tool to comprehend chemical properties of atoms
• Light is oscillations of electric and magnetic fields
• Visible light is approximately midway through the electromagnetic
spectrum
• Monochromatic radiation occurs in a narrow band of wavelengths,
whereas polychromatic radiation consists of many
frequencies/wavelengths
• Hertz discovered the photoelectric effect, which allows electrons to flow
around a circuit in the presence of UV light
• Einstein theorized the wave-particle duality of light through the discovery
of photons
ATOMIC ENERGY LEVELS
• Electrons affect chemical properties of an atom, hence isotopes of an
element only have slightly varying physical characteristics
• Each gas has a specific emission and absorption spectrum
ATOMIC STRUCTURE
• The atom is composed of a nucleus and a surrounding electron cloud
• The nucleus contains protons and neutrons and is orbited by the
electrons
• Atoms are neutral in nature but can gain or lose electrons to become
charged ions
• An ion can be either a cation (+) or an anion (-)
• An atom can also share its electrons with other atoms to form a covalent
bond
• An element is defined by its number of protons
• An isotope of an element has differing amounts of neutrons to affect its
molecular mass
• Each element has been categorized into the Periodic Table of Elements
NOMENCLATURE
• For ionic compounds, the cation is named before the anion and altered
suffix.
• Carbon compounds are named using a prefix and suffix determined by
the number of carbon atoms and the nature of intermolecular bonds
respectively
• For inorganic compounds, the central atom is named first before the
numbered prefix and the name of the other atoms
MOLES
• A mole of a substance is the amount of atoms found in 1g of a carbon-12
atom
• A mole is defined as approximately 6.02e23 atoms
• The molar mass of an element is the mass of 1 mole
• Molarity is the concentration of a solute in a solution
• Atoms combine in ratios of equal molar ratios as expressed in chemical
equations
CHEMICAL DEFINITIONS
• A compound is two or more elements chemically bonded together
• A molecule is two or more atoms of any kind that are chemically bonded
• The empirical formula is the simplest ratio of elemental combinations
• The molecular formula is the ratio of elemental combinations as found in
nature
MEASURING PRESSURE
Pressure can be measured using various devices:
• Barometer – a closed tube filled with liquid mercury used to measure
atmospheric pressure
• Manometer – a double sided tube with one end open to the atmosphere
and another to a pressure measured gas
, GAS LAWS
• Boyle’s Law shows that in an enclosed gas, volume is inversely
proportional to pressure and volume multiplied by pressure is constant
for each system
• Charles’ Law demonstrates that the volume of a gas is proportional to
its temperature
• Avogadro’s Law states that the amount of a gas is proportional to its
volume
• In combining these various laws we derive the Ideal Gas Law which
shows that PV = nRT
• The Law of Partial Pressures states that the sum of the pressures of each
individual gas is equal to the pressure of the overall system
MOLECULAR THEORY OF GASES
• Gases are composed of molecules of negligible size compared to their
overall volume
• Molecules move randomly at various speeds and their collisions are
perfectly elastic
• Average kinetic energy is proportional to temperature
• Pressure originates from the force created when molecules collide with a
surface or each other
• Average velocity of gas molecules: sqrt(3*R*T/(Molar Mass))
• Effusion is the escape of gases through a miniscule hole, whereas
diffusion is the mixing of various gases until the mixture is homogeneous
• Graham’s Law states that the rate of effusion and diffusion of two gases
(at equal pressure and temperature) is inversely proportional to the
square roots of their molecular masses
PROPERTIES OF LIGHT
• Has properties of refraction, diffraction and interference
• Light is used as a tool to comprehend chemical properties of atoms
• Light is oscillations of electric and magnetic fields
• Visible light is approximately midway through the electromagnetic
spectrum
• Monochromatic radiation occurs in a narrow band of wavelengths,
whereas polychromatic radiation consists of many
frequencies/wavelengths
• Hertz discovered the photoelectric effect, which allows electrons to flow
around a circuit in the presence of UV light
• Einstein theorized the wave-particle duality of light through the discovery
of photons
ATOMIC ENERGY LEVELS
• Electrons affect chemical properties of an atom, hence isotopes of an
element only have slightly varying physical characteristics
• Each gas has a specific emission and absorption spectrum
