Chemistry: Matter and Change

Flashcards covering key chemistry concepts including matter, states of matter, particle theory, pure substances vs mixtures, physical and chemical properties, phase changes, and physical vs chemical changes.

What is chemistry?

Chemistry is the study of matter, its properties, and its changes or transformations.

What is matter?

Matter is anything that has mass and takes up space.

What percentage of the universe's matter is composed of plasma, and in what forms does it exist?

Plasma makes up $99\%$ of the matter in the universe. On Earth, it exists as lightning, while in the universe, it exists in the form of suns and stars.

What is mass and what units are used to measure it?

Mass is a measure of the amount of matter in an object, measured in kilograms ($\text{kg}$) or grams ($\text{g}$).

What is volume and what units are used to measure it?

Volume is a measure of how much space matter takes up, measured in litres ($\text{L}$), millilitres ($\text{mL}$), or cubic centimetres ($\text{cm}^3$).

What are the core statements of the Particle Theory of Matter regarding particle movement and temperature?

Particles are always moving; as they gain energy, they move faster. Hotter temperatures result in faster particle movement, while colder temperatures result in slower movement.

What is an amorphous solid?

An amorphous solid is a solid whose particles are frozen in a disorderly pattern similar to that of a liquid, such as glass, plastics, rubber, obsidian, amber, and cotton candy.

How are pure substances and mixtures defined based on particle types?

A pure substance is made of only $1$ type of particle (same atoms or molecules), whereas a mixture is made of $2$ or more different types of particles.

What is an element?

An element is a pure substance that cannot be broken down into simpler substances by chemical means and contains only one kind of atom.

What is a compound?

A compound is a pure substance that is chemically combined and contains two or more different elements in a fixed proportion.

What is the atomic composition of water?

Water is composed of $2$ parts Hydrogen ($\text{H}$) and $1$ part Oxygen ($\text{O}$).

What is a homogeneous mixture (solution)?

A homogeneous mixture is a mixture where combined substances are mixed very well, individual substances are not clearly visible, particles are uniformly scattered, and any portion of the sample has the same properties and composition.

What are the two main types of heterogeneous mixtures?

The two main types are mechanical mixtures (where different parts are clearly visible, e.g. pizza, salad) and suspensions (where tiny particles of one substance are held within another, creating a cloudy mixture, e.g. tomato juice, milk).

Which separation method is used to separate fats from homogenized milk?

Centrifuge, which performs density separation by spinning.

How is matter categorized according to this classification chart?

Matter is divided into Pure Substances (which include Compounds and Elements) and Mixtures (which include Solutions/Homogeneous Mixtures and Heterogeneous Mixtures).

What is a physical property of matter?

A physical property is any property that can be observed or measured without forming a new substance or changing its composition.

What is ductility?

Ductility is a physical property describing how much a substance can be stretched without breaking.

What is viscosity?

Viscosity is a physical property describing the ability of a substance to flow or pour.

What is a chemical property of matter?

A chemical property describes the behaviour of a substance as it changes into a new substance or changes its chemical identity.

What are the characteristics of shape and volume for solids, liquids, and gases?

Solids have a definite shape and volume; liquids have a definite volume but take the shape of their container; gases have no definite shape or volume and fill whatever container they are in.

What is sublimation?

Sublimation is the process when a solid turns directly into a gas without turning into a liquid.

What is deposition?

Deposition is the process where a gas turns directly into a solid, which is the reversal of sublimation.

What is a physical change?

A physical change is a change in which the substance involved remains the same, changing only its state or form (shape), with no new substance created.

What is a chemical change?

A chemical change is a change in which the original substance is changed into one or more different substances with different properties, almost always forming a new substance.

What are the five clues that indicate a chemical change has occurred?

The five clues are: $1.$ Change in colour, $2.$ Production of heat or light, $3.$ Production of gas (bubbles), $4.$ Production of precipitate (solid in solution), and $5.$ The change is difficult to reverse.