chem exam 11 Flashcards
2024
What are Physical Properties?
Observable characteristics without changing substance
composition, such as colour, density, and texture
What are Chemical Properties
Behavior of a substance during a chemical change or
reaction, including flammability, reactivity, and toxicity
What are Physical Changes
Alterations in state or appearance without changing the
chemical composition, such as melting, freezing, or dissolving
What are Chemical Changes?
any change that causes a new substance to be formed.
Example: burning wood
What are
Exothermic Reactions?
Reactions that release energy in the form of heat or light,
such as combustion and oxidation.
What are Endothermic Reactions
Reactions that absorb heat from the surroundings, leading
to a decrease in temperature, such as thermal decomposition.
What is the Classification of Matter
Pure Substances .. elements and compounds
Mixtures; solutions and heterogeneous
What are
Groups
Vertical columns on the periodic table represent elements with similar chemical properties and the same
number of valence electron
What are Periods
Horizontal rows on the periodic table indicating the number of electron shells in an atom.
What are Ions?
Charged particles formed when an atom gains or loses
electrons, leading to a net positive or negative charge
What are
Cations
Positively charged ions formed when an atom loses electrons
What are Anions
Negatively charged ions formed when an atom gains an electron
What are Binary
Compounds
Compounds composed of two different elements, such as
sodium chloride (NaCl) and carbon dioxide (CO2
What are Monovalent Compounds
Compounds with a single possible charge and one covalent bond, such as sodium chloride (NaCl) and potassium
iodide (KI)
What are Bivalent
Compounds
Compounds with two possible charges and two covalent
bonds, such as calcium chloride (CaCl2) and magnesium
oxide (MgO)
What are Hydrates
Compounds containing water molecules in their crystalline
structure, often forming distinct hydrates with specific water-to-solute ratios.
What are Acids?
Substances that release hydrogen ions (H+) when dissolved in water, leading to acidic properties and pH values
below 7
What are Bases?
Substances that release hydroxide ions (OH-) when dissolved in water, leading to basic properties and pH values
above 7.
What is Hard Water
Water containing high concentrations of dissolved minerals, particularly calcium and magnesium ions, leads to
scale buildup in pipes and appliances
What is Soft Water
Water with low mineral concentrations, preventing scale
buildup and often achieved through ion exchange or distillation
What is Temporary Softening
Methods to reduce water hardness on a short-term basis,
typically through boiling or adding lime to precipitate calcium ion
What is Permanent Softening
Methods for long-term reduction of water hardness, such
as ion exchange using zeolite or the use of chelating
agents
What is electronegativity
Electronegativity is a measure of an element’s ability to
attract electrons
What is the difference between
ionization energy and electron
affinity?
Ionization energy is the energy required to remove an
electron from an atom. Electron affinity is the energy released when an atom accepts an electron
What is the law
definite proportions
A specific compound always contains the same elements
in definite proportions by mass
Boyles law what
is it
At a constant temperature, the pressure and volume of a gas are inversely proportional so if pressure increases
volume decreases
What is Gay-Lussac’s Law
At a constant volume, the pressure of a gas is directly
proportional to the kelvin temperature. so if pressure increases so does temperature
What is Charles’
Law
At a constant pressure, the volume of a gas is directly proportional to the kelvin temperature. so if volume increases
so does temperature.
What is Avogadro’s law
At a constant temperature and pressure, the volume of a
gas and the number of moles are directly proportional. So
if moles increase so does volume
Kinetic Molecular
Theory (KMT
The Kinetic Molecular Theory is a set of principles that
explains the behaviour of gasses at the molecular level. It
is based on the following postulates:
Gasses Consist of Particles: Gasses are composed of small particles, such as atoms or molecules. Constant
Random
Motion: Gas particles are in constant, random motion,
colliding with each other and the walls of the container. Negligible
Volume: The volume occupied by gas particles is considered negligible compared to the total volume of the
gas. Elastic
Collisions: Collisions between gas particles are elastic,
meaning there is no loss of kinetic energy Attractive or
Repulsive Forces: Gas particles neither attract nor repel
each other; they only interact during collisions.
