Matter & Chemical Change Flashcards

Flashcards covering key vocabulary and concepts from the provided lecture notes on Matter & Chemical Change (Science 9).

Atoms

Tiny particles that compose all matter.

Alkali metals

Extremely reactive metals.

Noble Gases

Gases that are not reactive.

The Particle Model of Matter

Can be summarized by five main points: All matter is made up of extremely tiny particles; There are spaces between these particles; Particles are attracted to one another; Particles are always moving; Particles move faster & farther apart when they gain energy

Solids

Particles are very close together (strong attractive forces). Particles do not move around very much because they don’t have a lot of energy. Solids thus maintain their shape in a given container.

Gases

Particles are very far apart (weak attractive forces). Particles move freely because they have a lot of energy. Gases thus expand until they fill the container they are in.

Liquids

Particles are able to move past one another because they have some energy. Liquids thus take the shape of the container they are in.

Mixtures

Contain two different types of particles.

Pure Substances

Contain only one type of particle.

Homogenous Mixture

If the particles are uniformly scattered, the mixture is said to be __.

Heterogeneous Mixture

If the particles are not uniformly scattered, the mixture is said to be __.

Solutions

Homogenous mixtures, or __, are usually clear and cannot be filtered to separate the particles

Mechanical Mixtures

Heterogeneous mixtures, or __, are further classified based on the size of their particles.

Suspension

A heterogeneous mixture made of large particles that are uniformly mixed but will settle if left undisturbed.

Colloid

A heterogeneous mixture composed of fine particles evenly distributed throughout a second substance.

Emulsions

A type of colloid in which liquids are dispersed in liquids (immiscible liquids, or those which do not dissolve in one another).

Physical Change

Substance changes in form but not in chemical composition; No new substances are formed; Change can be reversed

Chemical Change

Substance changes in chemical composition; A new substance is formed; Change cannot be reversed

Physical Property

Any property that can be observed or measured without forming a new substance

Chemical Property

Any property that describes how a substance reacts with another substance

Quantitative

properties are those which can be defined by a precise measurement (a numerical value).

Qualitative

properties are those which can only be described

Law

In science, a is used to summarize an observation.

Theory

the explanation of why that object falls to the ground, however, is known as a _

The Law of Conservation of Mass

States that during a chemical reaction, the total mass of new substances produced is always equal to the total mass of the original substances

Protons

Positively charged particles found in the nucleus.

Neutrons

Neutral particles found in the nucleus.

Electrons

Negatively charged particles that orbit the nucleus.

Atomic Symbol

Represents the element’s name

Atomic Number

Represents the number of protons in the nucleus

Atomic Mass

Represents the weighted average (in g/mol) of the masses of each naturally occurring isotope of that element

Anion

If an atom gains electrons, it becomes negatively charged and is referred to as an __.

Cation

If an atom loses electrons, it becomes positively charged and is referred to as a __.

Elements belonging to the same group

Have similar properties

Valence electrons

Electrons in its outermost orbital

Alkali Metals

Extremely reactive; rarely found in pure form because of how easily they react with other elements

Alkaline Earth Metals

Less reactive than alkali metals

Halogens

Extremely reactive; typically found in compound form; Very corrosive

Noble Gases

non-reactive elements

Compound

Consists of two or more different elements bonded together

Molecule

Consists of any two elements bonded together; elements can be the same, or they can be different

Diatomic

Elements which always bond together in their pure form are called __ elements.

Ionic Bond

Electrons are transferred between a metal and a non-metal

Molecular/Covalent Bond

Electrons are shared between two non-metals

Ionic Compounds

Strong bonds form between a metal and a non-metal when they gain or lose electrons to complete or get rid of a lone pair

Molecular Compounds

Weak bonds form between two non-metals when they share electrons to complete their valence shell

Reactants

substances that combine to produce a chemical reaction are always written to the left of the arrow

Product

the new substance that is produced as a result of the reaction is referred to as the product, and is always written to the right of the arrow

Exothermic Reaction

Chemical reactions that release heat or energy

Endothermic Reaction

Chemical reactions that absorb heat or energy

Formation Reaction

Two or more elements combine to form a compound

Decomposition Reaction

A compound is broken down into its individual components

Single Replacement Reaction

In a reaction between a compound and a lone element, one element in the compound is replaced by the lone element

Double Replacement Reaction

In a reaction between two compounds, one element in each compound is “swapped” with another element in the other compound

Combustion Reactions

A carbon-hydrogen compound (fuel) reacts with oxygen to produce water vapor and carbon dioxide

Reaction Rate

A measure of how fast a reaction occurs

Catalysts

Substances that can also be added to some chemical reactions to speed up their reaction rate.

Enzymes

Catalysts that speed up biological processes