chem exam 11

Question 1

What are Physical Properties?

Answer 1

Observable characteristics without changing substance
composition, such as colour, density, and texture

Question 2

What are Chemical Properties

Answer 2

Behavior of a substance during a chemical change or
reaction, including flammability, reactivity, and toxicity

Question 3

What are Physical Changes

Answer 3

Alterations in state or appearance without changing the
chemical composition, such as melting, freezing, or dissolving

Question 4

What are Chemical Changes?

Answer 4

any change that causes a new substance to be formed.
Example: burning wood

Question 5

What are
Exothermic Reactions?

Answer 5

Reactions that release energy in the form of heat or light,
such as combustion and oxidation.

Question 6

What are Endothermic Reactions

Answer 6

Reactions that absorb heat from the surroundings, leading
to a decrease in temperature, such as thermal decomposition.

Question 7

What is the Classification of Matter

Answer 7

Pure Substances .. elements and compounds

Mixtures; solutions and heterogeneous

Question 8

What are
Groups

Answer 8

Vertical columns on the periodic table represent elements with similar chemical properties and the same
number of valence electron

Question 9

What are Periods

Answer 9

Horizontal rows on the periodic table indicating the number of electron shells in an atom.

Question 10

What are Ions?

Answer 10

Charged particles formed when an atom gains or loses
electrons, leading to a net positive or negative charge

Question 11

What are
Cations

Answer 11

Positively charged ions formed when an atom loses electrons

Question 12

What are Anions

Answer 12

Negatively charged ions formed when an atom gains an electron

Question 13

What are Binary
Compounds

Answer 13

Compounds composed of two different elements, such as
sodium chloride (NaCl) and carbon dioxide (CO2

Question 14

What are Monovalent Compounds

Answer 14

Compounds with a single possible charge and one covalent bond, such as sodium chloride (NaCl) and potassium
iodide (KI)

Question 15

What are Bivalent
Compounds

Answer 15

Compounds with two possible charges and two covalent
bonds, such as calcium chloride (CaCl2) and magnesium
oxide (MgO)

Question 16

What are Hydrates

Answer 16

Compounds containing water molecules in their crystalline
structure, often forming distinct hydrates with specific water-to-solute ratios.

Question 17

What are Acids?

Answer 17

Substances that release hydrogen ions (H+) when dissolved in water, leading to acidic properties and pH values
below 7

Question 18

What are Bases?

Answer 18

Substances that release hydroxide ions (OH-) when dissolved in water, leading to basic properties and pH values
above 7.

Question 19

What is Hard Water

Answer 19

Water containing high concentrations of dissolved minerals, particularly calcium and magnesium ions, leads to
scale buildup in pipes and appliances

Question 20

What is Soft Water

Answer 20

Water with low mineral concentrations, preventing scale
buildup and often achieved through ion exchange or distillation

Question 21

What is Temporary Softening

Answer 21

Methods to reduce water hardness on a short-term basis,
typically through boiling or adding lime to precipitate calcium ion

Question 22

What is Permanent Softening

Answer 22

Methods for long-term reduction of water hardness, such
as ion exchange using zeolite or the use of chelating
agents

Question 23

What is electronegativity

Answer 23

Electronegativity is a measure of an element’s ability to
attract electrons

Question 24

What is the difference between
ionization energy and electron
affinity?

Answer 24

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

Question 25

What is the law
definite proportions

Answer 25

A specific compound always contains the same elements
in definite proportions by mass

Question 26

Boyles law what
is it

Answer 26

At a constant temperature, the pressure and volume of a gas are inversely proportional so if pressure increases
volume decreases

Question 27

What is Gay-Lussac’s Law

Answer 27

At a constant volume, the pressure of a gas is directly
proportional to the kelvin temperature. so if pressure increases so does temperature

Question 28

What is Charles’
Law

Answer 28

At a constant pressure, the volume of a gas is directly proportional to the kelvin temperature. so if volume increases
so does temperature.

Question 29

What is Avogadro’s law

Answer 29

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

Question 30

Kinetic Molecular
Theory (KMT

Answer 30

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.