Grade 10 Chemistry Definitions

A comprehensive set of vocabulary flashcards based on the Grade 10 Chemistry definitions including chemical reactions, atomic structure, and bonding.

Precipitation reactions

Chemical reactions where solids from when $2$ solutions of soluble salts react

lon exchange reactions

Reaction where the positive ion exchange their respective negative ions due to a driving force

Acid-base reaction

Reaction in which an acid reacts with a base to form a salt and water

Mole

SI unit for amount of substance

Avogadro's number

The number of particles in a mole of substance

Molar volume of gases

One mole of gas occupies $22,4\,dm^3$ at standard temperature and pressure

Concentration

The amount of solute per unit volume of solution

Stoichiometry

The study of the relationship between the relative quantities of substances taking part in a reaction or forming a compound, typically a ratio of whole integers

Hydrate

A compound, typically a crystalline one, in which water molecules are chemically bound to another compound or an element

Water of crystallisation

Water molecules forming an essential part of the crystal structure of some compounds

Percentage composition

The percentage by mass of each element in a compound

Decomposition reaction

A type of chemical reaction in which a single compound breaks down into $2$ or more elements or new compounds

Synthesis reaction

A type of chemical reaction in which $2$ or more simple substances combine to form a more complex product

Exothermic reaction

Reactions which transform chemical potential energy into thermal energy

Endothermic reaction

Reactions which transform thermal energy into chemical potential energy

Yield

The measure of the extent of a reaction, generally measured by comparing the amount of product against the amount of product that is possible.

Redox reaction

Reaction involving the transfer of electrons

Oxidation

The loss of electrons

Reduction

The gaining of electrons

Non-polar (pure) covalent bond

Electrons are equally shared due to zero difference in electronegativity

Polar covalent bond

When electrons are unequally shared due to a difference in electronegativity

Intramolecular bond

A bond between atoms within molecules.

Limiting Reagent/Reactant

Substance that gets used up first in a chemical reaction.

Avogadro's Law

Equal volume of all gasses, measured at the same temperature and pressure contain the same number of molecules.

Valency

The number of electrons in the outer shell of an atom which are able to form bonds with other atoms i.e the number of bonds the atom can form.

Molar mass

The mass in grams of one mole of that substance

Halide

Binary compound of a halogen with another element or group of elements

Oxide

An ion of oxygen ($O^{2-}$)

Covalent bonding

A sharing of at least one pair of electrons by two atoms.

Ionic bonding

A transfer of electrons to form cations and anions which are electrostatically attracted in an ionic crystal lattice

Metallic bonding

Attraction between between the positive kernels and a sea of delocalised electrons

Delocalized electron cloud

Electrons that are not at a specific point in a group of atoms

Molecule

When atoms share electrons, are bonded covalently, the resulting collection of atoms is known as a molecule

Covalent molecular structures

Crystal lattice that consists of separate molecules

Covalent network structures

Crystal lattice that consists of giant repeating lattices of covalently bonded atoms

Molecular formula

Concise way of expressing information about the atoms that make up a particular covalent molecular compound. Gives the exact number of each type of atom in molecule

Empirical formulae

Shows the simplest ratio of elements in the compound

Physical change

A change that does not alter the chemical nature of the substance, no new chemical substances are formed

Chemical change

A change in which the chemical nature of the substances involved changes, new chemical substances are formed

Law of constant proportions

Sometimes called Proust's law or the law of definite composition, states that a chemical compound always contains exactly the same proportion of elements by mass.

Law of Conservation of Mass

The total mass of substances taking part in a chemical reaction is conserved during the reaction

Dissolving/Dissolution

Solid ionic crystals breaking up into ions in $H_2O$

Dissociation

Process in which ionic compounds separate into smaller ions when dissolved in water

Hydration

Where ions become surrounded with water molecules in water solution (no IMF - only the polarity of the water molecule and the charge of the ions).

Electrolytes

A substance that contains free ions and behaves as an electrically conductive medium

Precipitate

The solid that forms in a solution during a chemical reaction

Sublimation

Process of going from solid to gas

Condensation

Process of going from gas to liquid

Kinetic Molecular Theory

All matter is composed particles which have a certain amount of energy which allows them to move at different speeds depending on the temperature (energy). There are spaces between the particles and also attractive forces between particles when they come close together

Relative atomic mass

The ratio of the average mass of one atom of an element to one twelfth of the mass of an atom of $\text{carbon-12}$

Atomic number (Z)

Number of protons in an atom

Proton

Particle found in the nucleus of an atom, it is positively charged

Electron

Smallest particle that makes up an atom and is found outside the nucleus, its negatively charged

Neutron

Particle found in the nucleus of an atom, it has no electrical charge

Mass number (A)

Number of protons and neutrons in the nucleus of an atom

Isotope

Isotopes are atoms of the same element that have the same number of protons ($Z$), but a different number of neutrons ($A$) resulting in different atomic masses

Aufbau Principle

Electrons orbiting one or more atoms fill the lowest available energy levels before filling the higher energy levels

Hund's rule

Electrons would rather be in a subshell on their own than share the orbital in the same energy level

Pauli's Exclusion Principle.

Electrons have a property of spin and two electrons must have opposite spin to share a subshell

Orbital

Region of space where you are most likely to find electrons

Valence electrons

Electrons found in the outermost energy level of an atom that can participate in forming chemical bonds with other atoms

Atomic radius

The measure of the size of the atom i.e. the distance from the centre of the nucleus to the point where the electron cloud ends

Group

Vertical column on the Periodic Table of Elements

Electron affinity

The amount of energy released when an atom in the gaseous phase gains an electron to form a negative ion

Electronegativity

The measure of the tendency of an atom to attract a bonding pair of electrons.

Chemical bond

Physical process that causes atoms to be attracted to each other and held together in more stable chemical compounds called molecules

First lonization energy

The amount of energy required to remove the first electron from an atom in its gaseous state to form a positive ion

Periodicity

Quality or character of being repeated at intervals

Mixture

A combination of $2$ or more substances, where these substances are not bonded or joined to each other and no chemical reaction occurs between the substances

Heterogeneous mixture

A mixture that consists of $2$ or more substances that is non-uniform and the different components of the mixture can be seen

Homogeneous mixture

A mixture that is uniform, and the different components cannot be seen

Element

A substance that cannot be broken down into other substances through chemical means

Compound

A group of $2$ or more atoms, attracted by relatively strong forces or bonds. The atoms are combined in definite proportions (fixed ratio)

Cation

A positive ion formed when a neutral atom has lost one or more electrons

Anion

A negative ion formed when a neutral atom has gained one or more electrons

Metalloids

Elements with mostly non-metallic properties and their distinguishing characteristic is that their conductivity increases as their temperature increases

Diffusion

The movement of particles from a high concentration to a low concentration

Brownian motion

Random motion of particles suspended in a liquid or gas resulting from their collision with quick atoms or molecules in the gas or liquid

Freezing point

The temperature at which a liquid changes its phase to become a solid

Boiling point

The temperature at which the vapour pressure of a substance equals atmospheric pressure

Melting point

The temperature at which a solid changes its phase or state to become a liquid. Process is called melting

Evaporation

Process of going from liquid to gas

temperature

Measure of average kinetic energy of particles in the substance.

Pure Substance

A material that consists of only one type of particle/matter that cannot be separated by physical means and has fixed/definite/constant physical properties eg. melting/boiling point.

Matter

anything that occupies space (volume) and has mass