Into to Chemistry

Color key

  • Already learned - #fffd42

  • Not as important - #73ff41

  • New Material - #4fb5ff

  • Important - #c852ff

What is Chemistry?

  • Chemistry is the study of matter and the transformation it undergoes

  • It’s about getting the atoms and molecules to rearrange

Matter

  • Has mass and takes up space

    • It’s the physical, substantial “stuff”

  • Energy is the capacity to do work or generate heat

    • Energy is not matter

    • Has not mass or volume

States of Matter

  • 3 states or matter

    • solid

    • liquid

    • gas

  • Plasma an ionized gas is a separate state

Solids

  • Have a definite shape and volume

    • does not depend on the shape of its container

  • Atoms or molecules in a solid are packed closely together

    • orderly arrangement - particles don’t move freely

  • Virtually incompressible

  • don't expand much when heated

Liquids

  • Have a definite volume but an indefinite shape

    • liquids take the shape of their container, but their volumes don’t change

  • Particles are close together, but not a rigid or orderly structure like in a solid

    • Particles can move around each other in a liquid

    • liquids can flow

  • virtually incompressible but do expand slightly when heated

Gases

  • Indefinite shape and volume

    • takes the shape and fills the volume of whatever container it's in

  • Atoms or molecules are much farther apart than liquids or solids

  • Relatively large distance between them means gases are highly compressible

  • Vapor and gas do not mean the same thing

    • Gas: substance that normally exists as a gas

    • Vapor: substance is normally a liquid or solid but is in the gas phase

Changes of State

  • solid to liquid: melting

  • liquid to gas: evaporation

  • gas to liquid: condensation

  • liquid to solid: solidification/ freezing

  • solid to gas: sublimation

  • gas to solid: deposition

Properties of Matter

  • Matter has both physical and chemical properties

    • Physical properties are those that you can observe without changing the identity of the materials

    • Examples:

      • density

      • melting/ boiling point

      • malleability

      • conductivity

      • luster

      • etc.

  • Chemical properties describe how a substance reacts/ changes

    • Examples:

      • flammability

      • breakdown into simpler substances

      • reaction with other substances

      • etc.

Physical Properties

  • hardness

  • conductivity

  • malleability

  • color

  • melting or boiling point

  • oder

  • physical state

Chemical Properties/Changes

  • chemical property: can only be observed when changing a substance’s identity (during a chemical reaction)

  • chemical change: produces matter with a composition that is different from the original matter (it’s not the same substance anymore)

  • new substance being formed

  • Some chemical and physical changes can look the same

Signs of a chemical change

  • color change

  • gas production/ bubbling

  • temperature change

  • formation of a precipitate

  • change in or producing an odor

Changes of matter

  • physical change

    • Properties of the material stay the same

      • boil, freeze, melt, splut,

  • Chemical change

    • produces matter with a different composition than the original material

      • breakdown of hydrogen peroxide into water and oxygen gas

Intensive vs extensive properties

  • intensive properties depend on the type of matter, but not on the quantity

    • depends on what it is and not on how much

    • do not change with the amount of materials present

    • Density is intensive

      • An increase in surface area means an increase in volume, more of the material means an increase in mass, so massvolume\frac{mass}{volume} remains constant

  • Extensive properties change with the amount of matter present

Identifying substances

  • substance

    • matter with a uniform and definate composistion

      • a substance is pure if it is make up of oe 1 type of atom or molecule

    • substances can have similar physical proporties to one another

      • ex. two metals may have the same luster, malleability, ect

Mixtures

  •    mitxture

    • physical blend of two or more components

    • they are everywhere

  • mixtures are classified based on how they are combined together

    • heterogeneous or homogeneous