Chemistry Unit 2

Matter & Chemical/Physical Changes

Matter

Anything that has mass and takes up space (volume)

What are some examples of things that are not matter?

Heat, radiation, light, thoughts

What are the 4 states of matter?

Solid, liquid, gas, plasma.

Extensive Properties

The properties dependent on the amount of matter present (variable that scales)

• mass

• volume

Intensive Properties

The properties that are not dependent on the amount of matter present (think of it as a constant)

• boiling point

• melting point

• density

Physical Properties

Can be observed and measured without changing the composition of matter

• some examples are: color, texture, odor, shape, and mass

  • Sates of matter are also physical properties

Chemical Properties of Matter

Can be observed or measured when one substance interacts with another

• transforms into a new substance

  • flammability

  • ability to rust

  • reactivity

  • acidity

  • toxicity

Physical Changes

A change in a substance that doesn’t involve changing the identity of the substance

• mixing

• pouring

• tearing

• breaking into smaller pieces

• phase changes

• dissolving

Chemical Changes

A change when 1 or more substances is converted into a different substance, a chemical reaction

• burning

• baking

• oxidation

• rusting

What are the signs of a chemical change?

• new color

• bubbling

• new solid forming

• spontaneous heat change

Pure Substance

matter made up of only one type of atom or molecule

• each sample has the same characteristics and chemical composition

• elements, compounds

Mixtures

A blend of two or more kinds of matter, each retaining its own identity and properties

• can be separated by physical means

Elements

A pure substance made of only one kind of element

• ex. pure substances made of only Carbon are diamonds and graphite

Compounds

A pure substance that is made from two or more elements that are chemically bonded

• cannot be separated by physical means

• ex. pure water, carbon dioxide, sodium chloride

Homogenous Mixture

A mixture that is uniform in composition, looking like one substance

• solutions are homogenous mixtures

• a substance that is dissolved in another is homogenous

• alloys are a type of homogenous mixture

Heterogeneous Mixtures

A mixture that isn’t uniform throughout, and you can see the different substances throughout

• contents differ from can sample to sample

Law of Conservation of Matter/Mass

Matter cannot be created or destroyed, and the total mass of the reactants must equal the total mass of the products

• reactants - starting substance

• products - substances that are formed

Law Conservation of Energy

Energy cannot be created nor destroyed, and can only be changed from one form of energy to another

• can be transferred from one object to another

Alloy

A homogeneous mixture of at least one metal